Newsletters on The REPL

103: Thunks, funding, and a Loom preview

Sat, 20 Nov 2021 13:15:42 +1300

Notes.

I’m happy to be able to say that I joined Whimsical today! Thanks to everybody who helped during my job search. I had some really great conversations with companies using Clojure, and I’m excited to be diving back into Clojure programming full-time.

-main

re:Clojure has announced their schedule and speakers for the 2021 conference. Lots of great names and talks, I’m particularly excited about Christoph Grand’s talk on Clojure for Dart.
Fogus has a new Thunks repo, a place to think through and discuss ideas. The first set of notes are on core.async.
Erik Assum talks about how he set up deploys to Clojars for clj-commons libraries based on a release tag.
Clerk has now been released. It lets you turn a Clojure namespace into a notebook, but also lets you use your existing Clojure editor. Jack Rusher has a Twitter thread with some examples of how he’s using it.
I talked with Renzo Borgatti about his book Clojure, The Essential Reference.
Whimsical (my new employer, and a Clojurists Together member) has raised $30 million in funding.
Nubank (also a Clojurists Together member, notice a pattern?) is targeting a $50 Billion valuation in an upcoming IPO.
Maurício Szabo has a good article on solving ClojureScript performance problems by taking advantage of Clojure’s data orientation by collapsing DOM nodes.
Sean Corfield has rebooted clojure-doc to a static site which can be regenerated from a new commit.
Brian Goetz has a minute and a half endorsement of Clojure.

Libraries & Books.

Jakub Holy has a new release out of clj-concordion, a library for writing Concordion tests.

Foundations.

GraalVM 21.3 is out with support for Java 17 and a bunch of improvements to both the Community and Enterprise versions.
Oracle has changed course and again will allow you to use the Oracle JDK for commercial use with no charge, starting with JDK 17 (Oracle’s OpenJDK builds are not affected by this change). There is a new Oracle No-Fee Terms and Conditions license that goes along with it, I’d recommend reading it carefully and understanding the implications if you’re going to switch.
Here is an overview of GC changes in JDK 17, and a preview of a big improvement to G1 remembered set size coming in JDK 18.
Java’s Project Loom is nearing a preview in the JDK.

The JDK implements virtual threads by storing their state, including the stack, on the Java heap. Virtual threads are scheduled by a scheduler in the Java class libraries, whose worker threads mount virtual threads on their backs when the virtual threads are executing, thus becoming their carriers.

Tools.

Cursive 1.12.0-eap1 is out and has support for tools.build, JetBrains Package Search, and better support for IntelliJ’s Code With Me feature.
Asko Nõmm writes about using a beefy remote server to run a large Calva development environment.
Making nREPL and CIDER More Dynamic from Lambda Island
Exoscale has another take on multi-module deps.edn projects.

Recent Developments.

Along with the previously mentioned CLJ-2664, there are a number of nice “quality of life” interop improvements coming to the next version of Clojure.

ClojureScript 1.10.891 was released. David Nolen wrote a good explanation of changes around implicit requires of Google Closure Library namespaces. It’s definitely worth taking the time to understand this and check your codebase for any uses of goog.object and similar that don’t have matching requires. Michiel Borkent has added a check for this in clj-kondo which will be available in the next release.
CLJ-1925 is adding a random-uuid function to Clojure to match up with the function in ClojureScript. Rich has marked it as OK so it looks like it will be included in Clojure 1.11.
CLJ-2667 adds functions to parse UUIDs, doubles, and longs from strings
CLJ-2668 adds predicates for NaN? and infinite? to Clojure.

Learning

Clojure Data Science is organising a number of the workshops at re:Clojure and a Data Science Special the next day. They’re looking for feedback on the Data Science Special.
Macrobrew: Clojure macros distilled from Abhinav Omprakash.
Mitchell Szczepanczyk gave a talk Researching “third way” democratically-run economies with Clojure(Script) to the Chicago Clojure meetup

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Latacora, Roam, Whimsical, Pitch, Nubank, Cisco, AppsFlyer, JUXT, Metosin, Solita, Adgoji, Nextjournal, Flexiana, Toyokumo, Griffin, and Parkside) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

102: Transducers, servers, and comments

Sat, 23 Oct 2021 14:51:42 +1300

Thanks to everybody who has contacted me about jobs or sent through tips on people that are hiring. I’ve had a lot of great conversations with people, one thing that’s been neat to see is how widely Clojure is being used across so many different industries.

-main

Reactive Clojure: You don’t need a web framework, you need a web language

Dustin Getz wrote an article describing the Hyperfiddle stack. Being able to seamlessly colocate client and server code will be extremely powerful, I’m looking forward to Photon being open sourced.

notion.site

Michiel Borkent on the ClojureScript Podcast

Jacek Schae interviewed Michiel Borkent about his recent move to working full-time on open source development.

clojurescriptpodcast.com

Fast and Elegant Clojure

Ben Sless refactored a slow Clojure implementation to various versions which are still idiomatic without sacrificing performance, and then finally a loop/recur form for when you need maximum performance. There’s also some neat custom transducers.

github.io

Grokking Clojure transducers

If you need a refresher on transducers before reading Ben Sless’s versions, this is a good article from Eero Helenius to develop an intuition for them.

solita.fi

Stressed Servers

Ben Sless also did some benchmarking on Clojure web servers, JVM garbage collectors, and routing frameworks. It’s also a good overview also of how to think about scaling web servers, and building a mental model of how they fail. You can pair it with Zach Tellman’s talk Everything Must Flow from a few years ago.

github.io

Speed up your ClojureScript Webapp

And on the frontend, Lucio D’Alessandro shows how to benchmark ClojureScript webapps and a bunch of optimisations you can use at different levels of your application.

juxt.pro

Asami: Turn your JSON into a Graph in 2 Lines

Paula Gearon spoke at the recent Strange Loop conference about Asami, an open source Datomic-like graph database that she’s built.

youtube.com

Clojurists Together September 2021 Monthly Update

Read the latest updates from a bunch of Clojurists Together funded projects including clojure-lsp, polylith, Holy Lambda, and Typed Clojure.

clojuriststogether.org

An Architect’s View: deps.edn and monorepos VII (Polylith)

Sean Corfield continues his series on monorepos, polylith, and developer workflow using Portal for VSCode to navigate through data.

corfield.org

Libraries & Books.

coffi

coffi is a new library for doing FFI (Foreign Function Interface) calls from Clojure to native code. Very cool and looks like it should be easier than other existing methods.

github.com

Rich Comment Forms

Rich Comment Forms are a new tool from the Hyperfiddle team for writing tests inline with your Clojure/ClojureScript source. They’ve put a lot of work on the developer experience for the tool, it looks useful for pairing and REPL driven development.

github.com

Lacinia reaches 1.0

Congratulations to Walmart Lab’s Lacinia reaching the 1.0 milestone!

github.com

salutem

salutem is a new health check library for sync / async health checks. This has clearly had a lot of thought and documentation put into it. The async health-checking in particular looks very useful.

github.com

Clojure src, test, and meta

Daniel Gregoire makes the case for having a meta folder along with src and test, and introduces metazoa, a library for inspecting and querying metadata. There’s also a video which discusses the motivations and use of the library more.

danielgregoire.dev

Foundations.

Amazon Corretto, A Journey into Latency Reduction

The Amazon Corretto JDK team gave a talk about why they built Corretto and talked more about the Shenandoah GC.

youtube.com

Tools.

clojure-lsp releases

clojure-lsp has had a bunch of releases recently with improvements. I’m happy to see all the progress, it’s going to have a big impact on lots of Clojure users.

github.com

babashka/neil

Neil is a new CLI to add common aliases and features to your deps.edn-based projects.

github.com

A preview of Clerk

Martin Kavalar recently released a preview and rationale for Clerk, a tool for converting a Clojure namespace into a notebook style interface. Avoiding out-of-order execution in particular looks like a very useful feature.

twitter.com

clojuby

clojuby is an interesting experimental project letting you use JRuby to talk to Ruby functions in a Clojure syntax, for example creating a Sinatra app from Clojure.

gitlab.com

Hiding whitespace is now remembered for each pull request | GitHub Changelog

GitHub isn’t directly a Clojure tool, but I find myself often enabling “Hide white space” when reviewing Clojure PRs. You can now set this permanently, rather than having to enable it on each PR you viewed. One downside to watch out for is that you might miss unintentional white space diffs.

github.blog

Clojure REPLs Deep Dive - YouTube

Nikita Prokopov explored the existing Clojure REPLs and Sublime Plugins for Clojure, how they work, and their pros and cons.

youtube.com

Meta Reduce 2021.2: Autumn Begins

Bozhidar Batsov has an update on the projects he’s been working on lately including the CIDER family.

metaredux.com

Recent Developments.

[CLJ-2664] Provide fast idiomatic access to java.lang.Math

There’s work underway to create a new clojure.java.math namespace which is easier to access from Clojure than java.lang.Math but with the same level of performance. The patch is an interesting read to see heavy use of inlining.

atlassian.net

CLJS-3330: Flag for legacy loading of goog.object & goog.array

Previously you could assume goog.object and goog.array were always available for use in your ClojureScript files without requiring them. However, if I’m reading the patch and discussion correctly, the new approach will be to always require any goog.*namespace that you’re using.

No changes needed yet, but I’d start to look out for this. It sounds like clj-kondo will be able to lint for it which will make updating your code a lot easier.

github.com

Learning.

October 2020 Plans & Hopes for Clojure Data Science

Daniel Slutsky has this month’s scicloj post where people talk about what they’re working on in the Clojure data science community. I’ve been impressed by scicloj and their consistent efforts to improve the Clojure data science ecosystem. They’re also looking to run workshops for the upcoming re:Clojure conference.

clojureverse.org

Dmitri Sotnikov - Engineering for Scale in Clojure

Dmitri Sotnikov was recently on the RH podcast talking his work introducing Clojure at SIM University Health Network.

anchor.fm

Finding my inner Wes Anderson with Babashka

Tim Zöller uses Babashka and AppleScript to query the Apple Photos photo database.

javahippie.net

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Latacora, Roam, Whimsical, Stylitics Pitch, Nubank, Cisco, AppsFlyer, JUXT, Metosin, Solita, Adgoji, Nextjournal, Flexiana, Toyokumo, Griffin, Parkside, and Doctronic) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

101: Brave Clojure job board relaunch, Michiel Borkent quit his job, and I'm looking for work

Fri, 08 Oct 2021 13:00:27 +1300

Recently, I’ve been working on a new office and have finished painting and flooring. I still have a few things left to do: painting and installing the skirting, getting a heat pump installed, wiring up ethernet, and installing acoustic panels to reduce echo.

I’m also looking for my next job. I recently left my job at GitHub as a Technical Program Manager to move back to writing software. I learned a lot of valuable things at GitHub including that my true passion lies in writing software. If you know of any companies that are hiring and open to New Zealand based employees/contractors, let me know. Thanks!

Lastly, a housekeeping note that there is now an RSS feed available for The REPL newsletter, you can find it at https://www.therepl.net/subscribe/.

-main

Adrian Smith on Membrane and UI frameworks

Nikita Prokopov talks to Adrian Smith about Membrane and UI frameworks.

youtube.com

A Better Clojure Job Board

The Brave Clojure jobs board has been relaunched and now includes free listings, and import from other sites. You can still pay to promote your listing (you should pay though!). I’ve found the new site very helpful.

braveclojure.com

“This week I took a hard decision: I quit my long-time job to work more on #clojure OSS.”

In more job related news, congratulation to Michiel Borkent for going full time on his open source Clojure projects! He’s created an amazing variety of projects already while working a full-time job, I can’t wait to see what comes next. I’m happy Clojurists Together was able to help, along with many other generous companies and developers. If you want to support him, you can do so using GitHub Sponsors

twitter.com

Shipping Clojure code with Paulus Esterhazy

I talked with Paulus Esterhazy about how Pitch ships code.

therepl.net

Clojure pre-history with Chris Houser

I also talked with Chris Houser about Clojure pre-history, features of Clojure and how Clojure’s principles can be applied elsewhere.

therepl.net

Faster JSON parsing with Erik Assum

And I also talked with Erik Assum about how he sped up JSON parsing in clojure.data.json, clj-commons, and he interviewed me about what I’ve been up to recently.

therepl.net

re:Clojure 2021

The re:Clojure CFP is closing on 10th of October. This is the last Clojure conference of 2021, so if you have a talk idea, now’s the time to submit it.

reclojure.org

Thoughts on Clojure UI framework

Nikita Prokopov outlines ideas for a new Clojure framework for desktop apps. This work is funded by Roam Research and Clojurists Together.

tonsky.me

Libraries & Books.

“It was fun 18 months for me as a maintainer of Rum.”

Roman Liutikov and Nikita Prokopov are looking for a new maintainer for Rum.

twitter.com

Foundations.

“Today is OpenJDK 17 release day.”

OpenJDK 17 was released recently, and you can download a copy from https://adoptium.net. I haven’t heard of too many issues with upgrading, but let me know if you see any.

twitter.com

How much faster is Java 17?

Good analysis comparing JDK 17 to JDK 11 and JDK 16. There’s a nice (but small) performance boost on their very CPU heavy code. I wouldn’t necessarily expect as big a speed up on most code, but it’s still worth upgrading for.

optaplanner.org

clj-easy/graal-build-time: Library to initialize Clojure packages at build time with GraalVM native-image.

Graal’s native-image is deprecating the --initialize-at-build-time flag. This was commonly used in Clojure builds, graal-build-time provides an alternative build method so you don’t need to list each package manually.

github.com

JEP 410: Remove the Experimental AOT and JIT Compiler

The AOT compiler was removed from the main JDK distribution due to low usage, but it remains part of GraalVM. Don’t miss this clarification from the GraalVM lead that AOT native image is still going to be developed in Graal, this only affects the hybrid HotSpot/AOT approach which few used.

java.net

Tools.

api-diff

api-diff can print a list of API diffs between library versions. Another useful tool from Michiel Borkent.

github.com

Why We Killed Our End-to-End Test Suite

Nubank switched from End-to-End testing to Contract and Acceptance testing to speed up their CI time. They show how it reduced cycle time and increased their deploys/week metric. Slow/flaky CI is a common problem at larger companies, it was good to see this shown as one possible solution.

nubank.com.br

Native Clojure with GraalVM

A good guide to building native-image Clojure apps, especially when you’re using Clojure libraries with dynamic class loading. It also shows startup time going from 6 seconds to ~1 millisecond!

convexhuman.com

Vlojure

Ella Hoeppner has released Vlojure, a very unique visual programming environment for Clojure. Check out the demo video too.

twitter.com

Cursive 1.11.0 is out!

Cursive 1.11.0 is out with support for Babashka, better support for spellchecking, and some tools.deps fixes.

twitter.com

Travis CI security incident

In early September, Travis CI had a security incident which leaked secure env vars. If you’re using Travis CI, it’s a good idea to cycle all of your credentials.

twitter.com

Allow CIDER to load its own middleware via the sideloader

CIDER can now upgrade an nREPL connection to one with CIDER’s middleware. This lets you jack in to a running nREPL session and get all of CIDER’s features.

github.com

Recent Developments.

CLJ-2350 Improve keyword aritiy exception message

A nice patch from Marc O’Morain to improve error messages when you call keywordwith the wrong number of arguments.

github.com

Learning.

Clojure deftype with unsynchronized-mutable

Dainius Jocas explains when you’d want to use unsynchronized-mutable and volatile-mutable in a deftype.

jocas.lt

Setting up a basic Clojure backend

Let Arne Brasseur take you through setting up a basic Clojure web backend.

youtube.com

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

100: Classloaders, Clojurists Together, and Crux

Mon, 06 Sep 2021 22:00:27 +1200

Notes.

New Zealand has been under lockdown for the last month to stop the spread of COVID. Our kids have been home from school and kindergarten. They’ve been very well behaved, except for the time they flooded the bathroom with a toilet paper/water slurry!

Things are starting to open up on Wednesday for most of the country. I also got my first COVID vaccination which was good. NZ was pretty slow to start rolling out vaccines but things are now moving very quickly.

This week I’m trying a new tool for preparing the newsletter. As a side effect the format is a little different and more expanded. Reply to this email to let me know what you think. Good change? Bad change?

-main

Banking and Clojure with Allen Rohner

I restarted The REPL podcast last week. This episode was with Allen Rohner talking about the bank he’s building, building Clojure with Bazel, and type-checking with spec.

therepl.net

Simple Made Easy - 10 year remaster

Strange Loop has released a 10 year HD remaster of Simple Made Easy. An oldie but a goodie, worth a rewatch.

youtube.com

Clojurists Together’s Long-term funding selections

Clojurists Together members recently voted for six developers to receive $1.5k/month for 12 months to encourage long-term projects. The six recipients were Bozhidar Batsov, Michiel Borkent, Dragan Djuric, Thomas Heller, David Nolen, and Nikita Prokopov.

Special thanks to all the Clojurists Together members who voted and funded these developers, and to Whimsical and AppsFlyer for joining to help us fund an extra three developers.

clojuriststogether.org

Clojurists Together Q3 2021 Funding Announcement

Clojurists Together is also funding 9 projects for Q3 2021: shadow-cljs, clojure-lsp and Malli with $9,000, clojurians-log-v2, PCP and Holy Lambda with $2,000, and Dependabot Core, Typed Clojure and Polylith with $1,000.

clojuriststogether.org

Writing Mobile apps in ClojureScript in 2021

Alex Davis writes for the JUXT blog about building mobile apps with ClojureScript in 2021. A good survey of the landscape and some tips which will save you time if you’re working in this area.

juxt.pro

The JUXT Clojure Radar 2021

JUXT has updated their Clojure Radar from 2016. I don’t have opinions on everything they mentioned, but I agree with their assessment on all of the tools I have experience with. Well worth a read to look for some promising Clojure technologies that might have slipped by. I was also happy to see that Clojurists Together had funded about 1/3 of the projects listed on the radar.

juxt.pro

Crux Development Diary #6

Crux has a development diary with a bunch of updates. Some of the changes are: adding HyperLogLog for better join estimates, new extension points for full text search, support for Google Cloud Storage via a neat NIO Filesystem Provider for GCS, support for Datomic style return maps, and a Learn Crux Datalog Today website.

They’re also making some very big upgrades to support even more advanced time based querying, adopting Apache Arrow for column-oriented indexing, and moving the index to object storage. This will let the index scale beyond local disk size.

Crux is also getting a lot of interest from Egeria, a Linux Foundation project for handling metadata around enterprise data warehouses.

opencrux.com

Libraries & Books.

Split tokens in Clojure

Miika Koskinen has created a library for implementing split tokens in Clojure. I did this when I was building Deps, but hadn’t thought to publish it as an open source library. It’s an easy pattern to use once you get your head around it, with not much increase in complexity.

quanttype.net

honeysql 2.0

Sean Corfield has released HoneySQL 2.0. It uses different identifiers for artifacts and namespace so you can use HoneySQL 1 and 2 in the same project and gradually migrate. One of the big changes is that HoneySQL will come with support for database specific extensions, previously you needed to use a separate library for this like Nilenso’s honeysql-postgres I’ve already started using HoneySQL 2 for some Postgres specific logic and it was a very smooth process.

cljdoc.org

Pathom 3 Alpha

Wilker Lucio has released an alpha for Pathom 3.

wsscode.com

Foundations.

The Classpath is a Lie

Arne Brasseur has a post on how “the classpath” is a lie/abstraction over a hierarchy of classloaders.

Also recommended from the post is Daniel Smulewicz on how classes are loaded dynamically in Clojure.

lambdaisland.com

“Elastic Metaspace” new classroom for the Java Virtual Machine

SAP has made an enhancement for JDK 16 to improve how the Metaspace allocates memory. The metaspace holds class metadata. As every function in a Clojure program is implemented as a class, improvements here should be help. I’m not sure if there will be a big improvement for the typical Clojure app though, as it seems to mostly improve behaviour with lots of classloaders and classes being unloaded.

sap.com

Good-bye AdoptOpenJDK. Hello Adoptium!

AdoptOpenJDK has joined the Eclipse Foundation as Eclipse Adoptium and added a bunch of confusing terminology in the process. AdoptOpenJDK 8 is now called Termurin 8. The new JDK’s will use the Java Compatibility Kit (JCK) for additional assurance that they are compliant with the Java spec.

Also of note, if you’re using GitHub Actions’ setup-java action, you’ll need to update your distribution to reference termurin.

adoptopenjdk.net

Tools.

Clojure - Source Libs and Builds

The Clojure core team is working on tools.build, a new library to fill in the missing (first-party) gaps around using tools.deps, deps.edn and the Clojure CLI to build artifacts. The build files are regular Clojure files and look quite similar in spirit to build.boot files. It looks like the build files could be a bit boilerplatey but I imagine that people will create higher-level libraries you can use to handle the most common use-cases.

There’s also a new command in the Clojure CLI to add a dependency to your deps.edn file, e.g.

clj -Ttools install io.github.clojure/tools.deps.graph '{:git/tag "v1.0.63"}'

clojure.org

alekcz/pcp: PCP: Clojure Processor

PCP is a Clojure Processor which runs in a similar fashion to PHP. Also of note, Alexander Oloo is being funded by Clojurists Together this quarter.

github.com

eastwood changes

Eastwood has had a bunch of work done on it recently, including a new :performance linter.

github.com

helins/maestro.clj

Adam Helinsky has a new pattern for managing a monorepo using deps.edn and Babashka. All dependency data lives in one deps.edn file and external dependencies are broken out into separate aliases. It seems like it might get a little unwieldy, but it would also be a good way to ensure everyone is using the same dependencies.

github.com

Introducing incomplete: A Simple Clojure Code Completion Library

Bozhidar Batsov released incomplete, a new Clojure code completion library extracted from nREPL.

metaredux.com

seancorfield/build-clj

Sean Corfield has built a library to abstract common build tasks for tools.build into a library so that your build.clj can stay small.

github.com

EmacsConf Call for Proposals

EmacsConf has a call for talk proposals open until September 30, 2021.

emacsconf.org

deps.edn and monorepos V

Sean Corfield continues writing about their monorepo and migrating to polylith.

corfield.org

Recent Developments.

CLJ-2123: Lighter-weight aliasing for keywords

It looks like there is going to be a new :as-alias option added to :require in the ns form. This will let you create “synthetic” namespaces that don’t have to exist before the :require is run. This is likely to be most useful for spec to let you use namespace qualified keywords without actually creating the namespace.

atlassian.net

Learning.

Learn Datomic

Jacek Schae has a new video course out for learning Datomic, Datalog and Datomic Ions. You can purchase it on it’s own, or as part of a subscription to ClojureStream which has all of his courses (re-frame, reagent, reitit, and Datomic) included.

Jacek also donates a portion of sales to Clojurists Together and has raised over $10k to date!

learndatomic.com

Learning Clojure, Interactive Programming and Deliberate Practice

Michael Fryar talks about using deliberate practice to learn Clojure after the company he worked for was acquired by Nubank.

github.io

Hey Webpack, Hey ClojureScript

David Vujic explains how to to build AWS Amplify apps with ClojureScript, chaining together shadow-cljs to Webpack.

blogspot.com

Misc.

Evidence of Fraud in an Influential Field Experiment About Dishonesty

I enjoyed reading this analysis of likely fraud in a research study into dishonesty. There was lots of evidence that the data was fabricated, but my favourite was that half the data used the Calibri font and half used Cambria.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Latacora, Roam, Whimsical, Pitch, Nubank, Cisco, AppsFlyer JUXT, Metosin, Solita, Adgoji, Nextjournal, Flexiana, Toyokumo, Griffin, and Parkside) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

99: Zig, comment forms, and threadpools

Tue, 20 Jul 2021 21:30:27 +1200

Notes.

I’ve been a bit sick this week, and the kids have been sick the two weeks prior. I’m looking forward to leaving winter behind for this year!

-main

Rich Hickey’s talk on a history of Clojure is out now. The paper is here. You’ll also get to see Rich’s office (?) with a bunch of neat musical instruments.
How are Clojurians handling control flow in their projects?
Clojure Morsels is a new Clojure newsletter, check it out!
I’m really excited about the next phase of Clojurists Together
Nikita Prokopov wrote about his experience in the International Conference on Functional Programming using Clojure and Zig.
An interview with Juan Facorro on ClojErl

Libraries & Books.

rcf (Rich Comment Forms) is a new Clojure/Script library that lets you write usage examples with results and turn them into tests. Similar to doctests in Python.
Lambda Island have an open source update with a bunch of changes to their open source projects. I’m particularly excited about fetch.

Foundations.

An old gist on sizing Java threadpools, but one I hadn’t seen before. The advice on global thread pools applies to Clojure’s pmap and future functions.
Programming Language Memory Models by Russ Cox reviews different language memory models including Java’s.
io_uring is not an event system.

Tools.

Happy birthday to CIDER, it turned 9 last week. What a legacy, Bozhidar and all of the other contributors to CIDER should be proud.
tylr.fun is an interesting take on text editing. I especially like how it handles placing parentheses.
Sean Corfield has a nice writeup on their use of the Polylith application architecture.
How to publish Clojure libraries on Maven Central from the JUXT team
Writing C Code in Clojure/Java using GraalVM

Learning

Misc.

I was wrong. CRDTs are the future

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Latacora, Roam, Pitch, Nubank, Cisco, JUXT, Metosin, Solita, Adgoji, Nextjournal, Flexiana, Toyokumo, Griffin, and [Parkside][parkside]) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

98: Automatic lambdas and Lilliput

Mon, 21 Jun 2021 11:39:24 +1200

-main

A post from Arne Brasseur about some changes for how Lambda Island makes videos. Making changes like this can be tough, but it seems like this is going to be more sustainable.

Libraries & Books.

re-frame-flow helps you visualise a chain re-frame events.
Methodical is a replacement for Clojure’s multimethods. It adds some neat features from the Common Lisp Object System, like adding wrapper methods, and the ability to call the next most specific method (kinda like calling a “superclass” but against the multimethod hierarchy). 0.12.0 is out now.
recife is a library for running TLC/TLA+ models for model checking.

Foundations.

OpenJDK has a new project Lilliput. The goal is to explore reducing Java’s object header size (in Hotspot) from 128 bits to 64 bits or less. As you can imagine, if succesulf, this would have a substantial impact on Java’s memory footprint.

Tools.

A patch for adding Clojure language support to Git’s diffs. You can add this yourself to your own Git config, but it’ll be nice to have it built-in.
A syntactic differ for Scheme. Similar to the excellent but underused autochrome.

Recent Developments.

Tsutomu Yano posted a new patch to support automatic lambda conversions for IFns.
Modern JS with CLJS: class and template literals

Learning

Better performance with Java arrays in Clojure - a 125x speedup using areduce over Java arrays.
An interesting proposal for a web app architecture. The server would send DOM updates over a websocket to the client (similar to Phoenix LiveView). See more discussion on ClojureVerse.

Misc.

Colin Fleming shared this to the Clojure subreddit - A strong commitment to backwards compatibility means keeping your mistakes

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Latacora, Roam, Pitch, Nubank, Cisco, JUXT, Metosin, Solita, Adgoji, Nextjournal, Flexiana, Toyokumo, Griffin, and [Parkside][parkside]) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

97: 250 KLOC, 400 macros, and $750 million

Mon, 14 Jun 2021 14:57:10 +1200

Notes.

Lots going on in Clojure this week!

-main

:clojureD was recently held online, the talks should be up on YouTube soonish.
Nubank raised a staggering $750M last week, on top of a $400M round in January. Nubank plans to use the funding to launch in Mexico and Colombia, launch new products and services, and hire more employees. That still seems like a lot of money, I’m excited to see if there’s anything else they plan to do with it.
The Stack Overflow Developer Survey is on right now. I’d encourage all Clojure developers to fill it out to help the Clojure community be represented.
Chris Nuernberger gave a talk on High Performance Data for the London Clojurians Meetup. Chris (along with others in the scicloj community) has been pushing Clojure a long way in the data analysis/data processing space.
Alex Miller has started Clojure Deref, a link/news roundup for the Clojure ecosystem. If you like this, you should check out Deref too.
Jordan Miller continues her podcast Lost in Lambduhhs with Alex Miller.
Nathan Marz gives us a tour through their 250k line Clojure codebase. That’s a pretty large Clojure codebase, and it sounds especially dense with 400 custom macros (Clojure’s source has 127). However, they’re building a programming language on top of Clojure so it’s perhaps not too surprising. Nathan Marz answered a few followup questions on the Clojure mailing list, including a few more hints on what they’re doing with continuations. I’m looking forward to seeing more.

Libraries & Books.

mprop is a nice extension to test.check with two useful extensions: localising test.check failures to the assertion, not just the test; and scaling the number of tests based on environment so you can run 10x more in CI than in local dev.

People are worried about Types. ?

Jacek Schae talked to Tommi Reiman about Malli
snoop adds some syntactic sugar to define Malli function schemas.

Foundations.

Crux has a Bibliography of books and papers that inspired Crux’s philosophy and architecture.

Tools.

Tips and tricks on how to use Clojure with GraalVM from Lee Read
Michiel Borkent continues churning out useful Clojure tools This time it’s scittle, a lightweight tool for running ClojureScript directly in the browser with no precompilation. View source on the linked page to see what it looks like, very cool!
An alpha for Expectations 2.0.0 is out, if you use Expectations, now would be a good time to give your feedback.
Christophe Grand and Baptiste Dupuch continue to do good work on extending Clojure to Dart
A list of OSS datalog databases (from the Crux team). The comparison looks fair, no one vendor gets all ✔️’s.

Learning.

An interactive guide on how to build a tetris game in ClojureScript from Shaun Lebron. Even if you don’t want to build a game, it’s worth reading, just to see an example of how you can make code explanations much more tangible.

Misc.

I’ve recently started stretching to end my day. It’s a good wind down routine to relax your muscles. There are a bunch of videos on YouTube to pick from, depending on how much time you have and how flexible you are to start with.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Latacora, Roam, Pitch, Nubank, Cisco, JUXT, Metosin, Solita, Adgoji, Nextjournal, Flexiana, Toyokumo, and Griffin) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

96: A Clojure year in review

Sun, 23 May 2021 21:46:07 +1200

Notes.

Welcome back to The REPL! This is the first newsletter since April 2020. Lots has changed in the world since then for me and almost certainly for you as well.

When I last wrote in April 2020, I had been laid off due to the startup I was working for shutting down after failing to raise funding. Since then the world went through COVID and lockdowns, I started a new job at GitHub working on GitHub Sponsors, sold our house, bought a new one, had our first child start school, and generally have had an extremely busy 12 months.

I want to say a big thanks to everyone who helped out with leads on jobs, I really appreciated it.

Here’s some of the key developments of the last year in Clojure (as I remember them).

-main

Probably the biggest Clojure news of the year was Cognitect getting acquired by Nubank.
Cognitect is sponsoring dozens of Clojure developers through GitHub Sponsors.
The State of Clojure 2021 survey results were published.
Clojure 1.10.3 and 1.10.2 were released, including a key fix for Graal based projects.
Nubank raised a $400M Series G round at a $25B valuation (!!)
CircleCI raised a $100M Series F round at a $1.7B valuation and acquired Vamp
Roam Research raised a $9M seed round at a $200M valuation
Clojurists Together formed a foundation and held board elections.

Libraries & Books.

re-frame hit 1.0.0 and has a new website, funded in part by Clojurists Together members.
Metosin released Malli, data-driven schemas for Clojure and ClojureScript. This was also funded in part by Clojurists Together members.
Chris Nuernberger (new Clojurists Together board member) released tech.ml.dataset, beating Pandas, dplyr, and Julia in performance.

Foundations.

“We should focus on stability in every JDK release, since every JDK release is meant to be ready for production use.” - Mark Reinhold on the meaning, or not, of “LTS”.
Ultra low pause time Garbage Collectors Shenandoah and Z are no longer experimental in JDK 15

Tools.

CIDER 1.0 (Sofia) was released.
There’s a new Clojure podcast Lost in Lambduhhs from Jordan Miller, interviewing Michiel Borkent.
Michiel has released far too many great things to list them all here, but babashka, clj-kondo, and sci are all amazing tools that have improved lots this year (partly funded by Clojurists Together).
If you were having trouble understanding all the different ways GraalVM can run your code then Java on Truffle — Going Fully Metacircular isn’t going to help matters - “GraalVM 21.0 introduces a new installable component, named espresso, which provides a JVM implementation written in Java.”
Clojars joined the GitHub secret scanning program.
Alex Miller wrote a guide to improving startup time in development.
Aaron Dixon from Red Planet Labs wrote about micro-optimizing Clojure for optimal performance. Clojure, Faster
A possible future for ClojureScript formatting in Firefox DevTools

Recent Developments.

There is a paper from Rich about the History of Clojure as part of the History of Programming Languages IV conference.
Fogus joined the Clojure core development team

Misc.

“It is not unusual at all to read a 20 year-old paper with a tool empirically shown to make programmers 4x faster at a task, and for the underlying idea to still be locked in academia.” - Developer Tools Can Be Magic. Instead, They Collect Dust

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Latacora, Roam, Pitch, Nubank, Cisco, JUXT, Metosin, Solita, Adgoji, Nextjournal, Flexiana, Toyokumo, and Griffin) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

95: Cornucopias and COVID

Tue, 14 Apr 2020 20:10:42 +1200

Notes.

My team and I were laid off today due to the pandemic. If you’re looking for senior engineers (Clojure or otherwise), then talk to Angus Fletcher, Ian Bishop, Cody Canning, or myself.

That means I’m now looking for a new remote job. I live in New Zealand but work on Pacific Time to sync up with engineering teams in USA and Canada. I have experience using Clojure and ClojureScript, but I’m also open to other languages. You can see my GitHub profile, LinkedIn, and personal site.

If you think I or one of my colleagues could be a good addition to your team, reply to this email and get in touch!

-main

I talked with Łukasz Korecki about mature Clojure codebases
Mike Thompson on whether re-frame is virtuous

Libraries & Books.

Rough for CLJS is a new library that wraps Rough.js to give your graphics a hand drawn style.
Darkstar is a Clojure library for making SVG’s from Vega and Vega lite specs. This is particularly cool because it uses GraalJS as the script engine to run Vega.

People are worried about Types. ?

Are tests necessary in Typescript? from Gary Bernhardt.

Foundations.

Flow Control in Aeron

Tools.

Bozhidar Batsov has a cornucopia of nREPL updates. What I really like about this post is it shows many Clojure tools are able to benefit from improvements to nREPL.
Mauricio Szabo talks about nREPL on Chlorine and implementing a nREPL Client.
Nativity is a tool for turning Babashka scripts into native-images. I imagine this makes them even more portable and can make startup run faster.

Recent Developments.

There’s a new release of core.async out with support for using JavaScript promises inside a go block.
An interesting stat I hadn’t seen before; over the last 12 months, unique IPs downloading Clojure from Maven Central went from ~75,000 to ~135,000. Unique IPs is a much better metric to use than raw download counts, raw download counts can sometimes end up counting uncached CI jobs.
CLJS-1543 Support Closure libs using goog.module.

Learning

Between Two Parens (still jealous I didn’t think of that name) has a good intro on the various parts of the Clojure CLI tooling suite.
React Contexts are dynamic scope

Misc.

I’ve been enjoying this new meme of Ghanan dancing pallbearers.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Pitch, Nubank, JUXT, Metosin, Adgoji, and Nextjournal) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

94: Data layout and visualisation

Thu, 09 Apr 2020 21:57:07 +1200

-main

Congratulations to CircleCI for raising a $100M Series E round this week!
Clojurists Together surveyed our members to see what they’re interested in. There’s still time to apply, or to encourage other Clojure developers to apply.
I talked with Łukasz Korecki about building with Clojure in a mature startup.
Lambda Island talked about the interceptor pattern, aka coffee grinders, and Jack Rusher added some more thoughts using the very cool Nextjournal.

Libraries & Books.

Nubank has published their fork of clj-kubernetes-api. This is a data-driven Kubernetes client derived from the Swagger specs, similar to Cognitect’s AWS API library.
Patika is a routing library building on Liberator and Compojure
Fulcro RAD is an experimental new library for Rapid Application Development.
There’s been an influx of Clojure state libraries lately. The latest is context which looks pretty full featured.

People are worried about Types. ?

What are types in Clojure?

Foundations.

A good Twitter thread on data layout in memory and its impact on performance, particularly in the browser.
Follow the thread up with a great outline of Java’s Project Valhalla
Coping with incompatible code in Graal VM AOT compilation, h/t Michiel Borkent for the link.

Tools.

Calva made a new release, the headlining feature is a debugger. I’m especially pleased to see this because the work was funded by Clojurists Together.
Reveal is a REBL style data browser. It’s early, but looks very cool. Check it out if this resonates with you: “Repl is a great window into a running program, but text representation is too limited for inspection.”
How to edit s-expressions in Vim without plugins from Jacob O’Bryant.

Learning

Lambda Island published their Coding Style Guide. It mostly builds on the Clojure Style Guide. I think I agree with almost everything in there, I’ll need to think a bit more about the last suggestion to use a platform namespace. I’d generally just use reader conditionals directly in a cljc file.
A recommender system in 30 lines of Clojure

Misc.

No Haunted Forests

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

93: The REPL Returns

Sun, 29 Mar 2020 13:29:58 +1300

Notes.

Welcome back to The REPL, a newsletter about Clojure and ClojureScript. Wolfram Alpha tells me it’s been 7 months and 5 days since the last newsletter. In the meantime quite a few things have happened!

I got to go to St. Louis to speak at Strange Loop
We tried to sell our house and buy another one, then put it all on hold
Clojurists Together has been separating from the SFC into our own 501(c)6 trade association
My wife gave birth to our third baby
A few other personal things which needed a lot of attention
and most recently, the worldwide spread of COVID-19

The REPL newsletter and podcast and my open source contributions all had to take a backseat to these other responsibilities.

As I write this, all of New Zealand is in lockdown to prevent the spread of Coronvairus. I’m fortunate to have a job working from home so my days haven’t looked a lot different so far. It’s not clear yet when New Zealand’s borders will be opening up again, so I’m glad I got to meet so many of you last year.

Far too much has happened in Clojure in the last seven months, but I’ll try and point out some of the key events.

-main

The State of Clojure 2020 results have been released. Alex Miller wrote up some thoughts on the open feedback section. I hope to finish my write up of this sometime soon.
Since the last newsletter, Clojurists Together has funded Expound, Deep Diamond, Oz, Reagent, Ring, Fireplace, and Calva.
Clojure Weekly is a new Clojure newsletter from dotemacs.
Rich Hickey launched a GitHub Sponsors profile.
Lambda Island launched an Open Collective for their open source and community work.
Clojure: a mature alternative to Java is a good summary of arguments for switching to Clojure.

Libraries & Books.

Most (all?) of the Clojure contrib libraries got a bump to 1.0 recently to reflect their stability.
James Reeves is working on Ring 2.0 and currently soliciting feedback on the new 2.0 spec. If you have the time, I’d highly recommend reviewing the spec and commenting if you have any questions. We’re going to be using Ring 2.0 for the next ten years, so now is the time to talk about it.
Hashp is a neat library with one weird trick for print debugging.
Łukasz Korecki wrote about the value of simple solutions, the RFC process at EnjoyHQ, and the resulting open source libraries eternity and lockjaw
Red Planet Labs wrote about how they serialize and deserialize functions instances betwen processes(!).
clip is a new state management library from JUXT. Dominic Monroe also discussed it on the JUXT cast.
systemic is another new state management solution similar to Component, Mount, and Integrant.

Foundations.

GraalVM 19.3 is out with support for Java 11.

Tools.

Michiel Borkent has released another great Clojure tool: Carve to remove unused vars from your Clojure program.
Hot off the press is nREPL 0.7
Stuart Sierra wrote about Clojure Start Time in 2019
tools.deps.graph shows a graph of your deps.edn dependencies, along with the size of each JAR.
There was a state of CIDER survey, and the results were interesting. Take a read, you might discover some great CIDER features you didn’t know about.
lein-git-inject is a neat solution for building a version from your git tags.

Recent Developments.

Clojure 1.10 introduced changes which caused issues with GraalVM’s native-image. CLJ-1472 tracked the underlying issue (which was first reported in the context of Android). This was recently fixed and is slated for inclusion in an upcoming Clojure 1.10.2 release.

Misc.

The epistemology of software quality

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

92: Reflections

Sat, 24 Aug 2019 19:49:26 +1200

Notes.

I have to start this newsletter with a correction. Last time, I said that I thought CircleCI was the Clojure company that had raised the most money. I was wrong, Nubank has raised $820 million dollars, and has a valuation over $10 billion dollars. That makes them one of the most highly valued fintech startups. For context Stripe’s most recent valuation in 2019 put them at $22.5 billion dollars.

Since the last newsletter I’ve been to Belgium and back for Heart of Clojure. It was a great event and I’m very happy I got to go. I met lots of readers and Clojurists Together members which was a big highlight for me.

-main

The talks from Heart of Clojure have just gone up, including my talk Building Stable Foundations
I wrote about why I think Heart of Clojure was so special. See also reflections from Fork This Conference, The people’s conference, The hallway track conference, Community with lots of heart, and A courageous conference?
What’s the state of error messages?
ClojureScript Pixel Game Engine With Blender Live-reloading
Frameworks and Why (Clojure) Programmers Need Them
I talked with Ambrose Bonnaire-Sergeant about his PhD in Typed Clojure.
Clojurists Together is funding Shadow CLJS with Thomas Heller, Meander with Joel Holdbrooks, Calva with Peter Strömberg, and CIDER with Bozhidar Batsov. This is thanks to the generosity of all of the members of Clojurists Together.
How CircleCI processes over 30 million builds per month
Beyond Clojurists Together is a page listing Clojure projects that you can support directly.

Libraries & Books.

Metosin continue to push performance boundaries, this time with porsas, an experimental set of tools for doing JDBC queries in idiomatic Clojure but with Java performance.
Erik Norman’s new book Grokking Clojure is out in Manning’s early access program. You can get a 50% discount with code MLNORMAND.

People are worried about Types. ?

Functional Works has written a very extensive guide to spec
Metosin has written about their motivations for Malli, their new data schema tool for Clojure/Script.

Foundations.

“Describing all non-copying relocating collectors as ‘Mark Compact’ is like referring to the bulk of zoology as the study of non-elephant animals.” - Mechanical Sympathy
If you’ve been hankering to mix your Rust code with Clojure, Rüstigraben is a work-in-progress to let you run Rust code in GraalVM.

Tools.

Speaking on Nubank, they’ve open sourced Workspaces, a devcards-like UI component development library.
salt is an experimental tool to convert a subset of Clojure into TLA+ (!)
Calva Funding and Reinforcements and more!
clj-kondo now has support for emitting analysis data
Also from Michiel Borkent, babashka lets you write a subset of Clojure in shell scripts or other places you need quick startup. sci is the Small Clojure Interpreter that is backing it.
jet, again from Michiel Borkent is a CLI tool for transforming between JSON, EDN, and Transit
Community Tools and Templates for Clojure CLI Tools
Setting up Neanderthal with REBL and Cursive from fellow kiwi Nick Jones.
lvh has written wernicke, a Graal based data redaction tool. This is especially useful for transforming production data into a form safe to use in tests.

Recent Developments.

Journal 2019.22 - spec updates, tools.deps

Learning

Parens of the Dead is back after a hiatus. These are screencasts building games in Clojure and ClojureScript. You can catch the first three episodes of season 2 on Twitch.
A quick summary of how to interop with JS from ClojureScript.

Misc.

Fast Software, the Best Software, and Performance Matters are two good reflections on performance.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Pitch, Nubank, JUXT, Metosin, Adgoji, and Funding Circle) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

91: Off to Belgium

Wed, 31 Jul 2019 17:28:42 +1200

Notes.

I’m writing this in the airport before leaving to go to Heart of Clojure. I’m really looking forward to meeting more Clojure people, there’s not many of us in New Zealand. I’ll be handing out Clojurists Together stickers, so come say hi!

-main

ask.clojure.org is a new Q&A site for asking questions about Clojure. It looks like it has a broader scope than questions that would be allowed on StackOverflow, but perhaps has some overlap with Clojureverse. I’m really enjoying seeing the Clojure core team experiment with different ways of communicating and engaging with the community. The announcement also mentions that this will be the new way for starting a problem report for Clojure, triaged issues will then migrate to JIRA.
If you enjoy a good old-fashioned bikeshed, then jump into this discussion about whether we should suffix names of boolean values with a question mark.
The Java Language Summit was on recently, and Ghadi Shayban spoke there about Clojure and how it interfaces with the JVM.
Jack Rusher talked about maria.cloud
Roman Liutikov showed how we can use Project Loom fibers and continuations in Cloure and async/await in ClojureScript.
JUXT has released a lot of things recently. If this keeps up I’ll need a separate section in this newsletter just for them. A Crux dev diary and new Crux tutorials are out. They have also released a new podcast out, and immediately touched the third rail, discussing whether a company should mandate a single editor for their developers. If that wasn’t enough, they are also putting on another conference: XT20.
CircleCI recently announced they raised their series D round, bringing their total investment to $111.5MM. I think this is the most that any Clojure company has raised, Climate Corp raised $107MM.
I talked with Eric Normand about teaching Clojure, and some of his new courses on The REPL podcast.

Libraries & Books.

Chris Nuernberger continues his dark magic, this time calling into Python from Clojure with libpython-clj. This was discussed on the most recent scicloj meeting.
panthera uses libpython-clj to work with Pandas dataframes from Clojure.

Foundations.

JDK 13 is in early access, and is scheduled for release in September 17, 2019. A few things I noticed which might affect Clojure users: the Socket API is being reimplemented, and there are some improvements to application class-data-sharing.
Amazon has released Amazon Corretto Crypto Provider which provides an optimized version of many cryptographic algorithms on the JDK. If you do any cryptography in your Java code (including TLS termination) it seems worth checking out. There are some impressive looking charts on the blog post.
This was a really well written article on the stack in Java, how stack overflows are detected, and some recent changes in JDK9 around the stack to make locking code safer.

Tools.

Howard Lewis Ship teaches us how to flex our scripting muscles using Joker

Recent Developments.

Alex Miller talks more about ask.clojure.org, tools.deps, and spec.
Performance improvements to ClojureScript from Mike Fikes continue to come, this time in source map creation.
CLJ-2075 would add three-arities to a bunch of equality and inequality operators, for a fairly significant speedup.

Learning

There are some very deep cuts in this Twitter thread about obscure Clojure knowledge. For example: (conj {:a 1} {:b 2}) => {:a 1, :b 2}.
JSON serialization for APIs in Clojure
There has been continued optimisations on Nikita Prokopov’s Clojure and Rust solutions to a programming competition problem, as well as more discussions.

Misc.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Pitch, Nubank, JUXT, Metosin, Adgoji, and Funding Circle) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

90: Tapes, Specters, and a farewell

Thu, 11 Jul 2019 15:45:16 +1200

Notes.

Falcon (my employer) still has two job openings, a Web Development Engineer (mostly front-end), and a Senior Software Engineer (mostly backend). If you’d like to work in an empathetic, inclusive, fast growing team that uses Clojure, please look at applying. We’re looking to hire people remotely (or in the Bay Area) who can work with a significant overlap in the Pacific time zone.

If you (or someone you know) haven’t done Clojure but are experienced in another language and would like to learn Clojure, we’re happy to teach you!

-main

Clojure/south is a new Clojure conference in Sao Paul, Brazil. It’s hosted by Nubank. Their CFP is open until July 21. The list of speakers already announced looks stellar.
I talked with Nathan Marz about his work at Red Planet Labs, Specter, and continuations.
Clojurists Together is going to be picking projects to fund very soon. If you’d like to get paid to work on an open source Clojure project that you maintain, consider applying. We also have a June update on what’s been happening with Fireplace.vim.
This is kind of bananas, Nextjournal are using GraalVM to render their Clojure_Script_ app in a GraalJS context. They then serve that rendered HTML from their Clojure app, which is running in the same JVM.
This reflection on Ten Years of Erlang isn’t directly about Clojure, but I think the Clojure community can learn a lot from it. I really liked the ’ladder of ideas’ concept, I’d be interested to see a similar ladder for Clojure.
I’m going to be speaking at Strange Loop this year on OSS sustainability. If you’re thinking of going, you can use code THEREPL for $50 off.
Ben Brinckerhoff on Effect-ive Clojure, managing side effects in Clojure. YouTube, Slides

Libraries & Books.

Release 0.5.0 of Deep Learning for Programmers by Dragan Djuric is available now.
test.check 0.10.0-RC1 is out now. If you use test.check (and you should), then give it a try to spot any bugs/issues before it gets released.
perc is a Clojure library that adds a lot more features to anonymous functions. Some of the examples look pretty wild, like #%/%(Point. %::x %::nearby/y %:foreign/z). If my anonymous functions got this complicated, I’d probably reach for a standard fn with named and destructured parameters, but this is certainly a very creative use of tagged literals!
tape is a library from Max Penet “for when Kafka is too much and durable-queue not enough.”

People are worried about Types. ?

Thoughts on spec
Metosin have released malli which is an alternative to both Spec and Schema.

Tools.

clojure-warrior 0.2.0, a VS Code Clojure extension is out.
Farewell, Grimoire. Note that Zachary Kim (ClojureDocs creator) disputes some of Bozhidar’s points in the article about ClojureDocs.
A basic guide to Clojure + deps.edn.
A guide on downgrading CIDER from the version on MELPA to MELPA Stable. I’m quite surprised that there still isn’t an easy solution for downgrading (or pinning!) Emacs packages to older versions. If I get really stuck, then I will usually restore from a Time Machine backup.
Bozhidar has some more updates on what he’s been working on. I’m really looking forward to finally meeting at Heart of Clojure this year.
nREPL now has a native EDN transport. This will be useful for ClojureScript clients that can more easily handle EDN than bencode, the main nREPL transport format.

Foundations.

Speaking of continuations, they’re coming to Java as part of Loom.

Learning.

Nikita Prokopov worked on a numerical problem in Clojure and Rust and found the Rust solution was 17x faster. The comments on Reddit are a decent starting point for this, especially Alex Yakushev’s comments, or you can read the original if you speak Russian.

Misc.

Name It, and They Will Come

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Pitch, Nubank, JUXT, Metosin, Adgoji, and Funding Circle) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

89: Typed Clojure, type systems, and new Datomic features

Sat, 29 Jun 2019 13:45:00 +1200

Notes.

If you (or someone you know) haven’t done Clojure but are experienced in another language and would like to learn Clojure, we’re happy to teach you!

-main

I talked with Dragan Djuric about Neanderthal, and his ambitious plans for writing and self-publishing multiple books about deep learning.
The Scicloj organizing team is looking for new members. Their next meeting is on July 18 too.
The (unofficial) Clojure Style Guide has a nice new website.

Libraries & Books.

A sketch on a new effect for re-frame :db-crud
Mike Fikes has ported Clojure’s bean function to ClojureScript. Why should you care?

This lets you interoperate with JavaScript objects in an idiomatic fashion, while being an order of magnitude faster than equivalent constructs using js->clj
I’m a little late on this, but Sean Corfield has published version 1.0.0 of his new JDBC library next.jdbc.
Schema has a new release 1.1.11 that fixes some bugs.

People are worried about Types. ?

Ambrose Bonnaire-Sergeant has published his PHD thesis on Typed Clojure (PDF). The new work is focused on improving the experience of using Typed Clojure based on industry feedback. I’m looking forward to reading this.
What Tim Baldridge wants from a type system.
Not a Clojure item, but this week Stripe open sourced Sorbet, their type checker for Ruby.

Tools.

Brian Marick had a thread on Twitter about testing frameworks, and some fundamental assumptions that test frameworks make about equality.
Workiva has open sourced eva, a clone (mostly) of Datomic. It sounds like they are not going to be doing a lot of active development on it anymore, and it’s unclear whether they’re using it themselves currently. Very cool nonetheless, and it has great documentation.
Speaking of Datomic, there is a new release which adds a bunch of very useful new data modelling and data validation features.

Tuples solve some thorny data modelling problems that I’ve faced in the past. Attribute predicates allow you to validate attributes match particular rules at the database level; previously you had to use transaction functions, or app level code to handle this (I think?). Entity specs let you define validation rules for an entity as whole, e.g. a user has an email address and a password. Return maps are a very cool feature that let you get maps back from a datalog query instead of tuples, while also being able to positionally destructure them.

Taken as a whole, these changes significantly improve Datomic’s native data modelling, querying, and data validation capabilities. I expect a lot of Datomic shops are going to be very happy with this update.\
Extending Neovim with Clojure

Learning

This was a good experience report on a first time contribution to nREPL, with some tips for others looking to start contributing to open source projects.
Ring’s idiosyncracies and the programming model for working with it.
Sean Corfield demonstrates using REBL to fix a bug in core.memoize.
A project workshop using Clojure and Kafka from the Clojure/Kafka consultancy Troy-West (Disclosure: I’ve worked with the director previously). This looks like a good way to learn Kafka Streams in a self-directed manner (or you could pay the authors to teach it to your company).

Misc.

Now for something completely different, I read and listened to a discussion about what happens if the cost of capital never rises again, and what that would mean for businesses and society. I have a tendency to assume that things will revert to the mean, and to the way they are ‘supposed’ to be (see NZ’s housing market bubble). This was a good reminder for me to keep an open mind that sometimes the world fundamentally changes.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Pitch, Nubank, JUXT, Metosin, Adgoji, and Funding Circle) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

88: Tempting fate, lots of journals, and JIRA!

Sat, 15 Jun 2019 07:37:55 +1200

Notes.

Since the last newsletter I’ve been over to America for work, and back home again. Things have been pretty busy with work, travel, family, e.t.c. but life is finally settling down a little bit. While I was in America I got to see a bunch of Clojure folk in San Francisco, New York, and even Chicago after weather stranded me there overnight. It was really great to meet so many people that I’d only interacted with online before, everyone I met was really welcoming and friendly.

Falcon (my employer) has two job openings, a Web Development Engineer (mostly front-end), and a Senior Software Engineer (mostly backend). If you’d like to work in an empathetic, inclusive, fast growing team that uses Clojure, please look at applying. We’re looking to hire people remotely (or in the Bay Area) who can work with a significant overlap in the Pacific time zone.

Let me know if you have any questions.

-main

Clojure 1.10.1 was released. It’s a pretty small release with a few very targeted fixes. It’s great that they were able to get released off-cycle and didn’t need to wait for Clojure 1.11. Thanks Alex and everyone else who got it out!
Jacek Schae has a new podcast out about ClojureScript and he’s had a stellar bunch of guests so far.
Bozhidar Batsov talked about Daniel Higginbotham’s recent tweet about Clojure Heroes. What was most striking to me was how many people I could think of that had contributed greatly to the Clojure community to make it the way it is today.
JUXT have been writing journal posts talking about what they’ve been up to lately.
Speaking of JUXT, I interviewed Jeremy Taylor and Malcolm Sparks on The REPL podcast about Crux, their new bitemporal database.
ClojureScript logging with goog.log from Lambda Island

Libraries & Books.

Michiel Borkent helps you tempt fate with finitize. It’s a library that lets you limit and realize possibly infinite sequences.
Get Programming with Clojure is a new Clojure book from Yehonathan Sharvit (creator of Klipse). It’s in early access with Manning at the moment.
supdate is a new library for transforming nested data structures. It’s similar to Specter.

People are worried about Types. ?

Ambrose Bonnaire-Sergeant successfully defended his thesis on Typed Clojure

Foundations.

How many type parameters can a Java method have?

Tools.

CIDER has a snazzy new docs site, Bozhidar talked about the migration process.
He also published an Meta Reduce, Volume 2019.2 with an update on what he’s been working on, as well as some tips for CIDER on REPL shortcuts and keeping your REPL tidy.
Datomic Cloud has a new option for direct HTTP connections to the Datomic VPC. Previously all HTTP connections had to go through a VPC Lambda proxy. This should greatly reduce cold-start times.

Recent Developments.

There’s a new page on clojure.org about Clojure’s development process. It explains the philosophy behind Clojure’s development process.
Alex Miller has more journal posts about what he’s been working on including a JIRA migration for dev.clojure.org (which must have been a huge amount of work). 17 , 18, 19, 20.
I’m particularly excited about that the Clojure core team is talking about having a separate way to create enhancement requests similar to PEP’s.

Learning

Deploying ClojureScript to GitHub Pages. This is from a new site called Between Two Parens; I’m jealous I didn’t think of that name first.
Cognitect has a (slightly old by now) blog post talking about the future of the conferences that they put on. They are going to be continue running Clojure/conj, but are discontinuing Clojure/west and EuroClojure. They are also going to be giving more support to community run Clojure conferences, which is awesome.
Building a ClojureScript wrapper for React with Hooks
Andy Chambers from Funding Circle has a blog post on the Confluent blog about Testing Event-Driven Systems using Clojure

Misc.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Pitch, JUXT, Metosin, Adgoji, and Funding Circle) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

87: Getting to the Crux of the matter

Thu, 25 Apr 2019 06:51:49 +1200

Notes.

The Falcon Project (my new employer) is looking for a web development engineer with a strong frontend emphasis. We’re looking to hire remote in the US/Pacific timezone (and close by is possible too). One of our core focuses is communicating privacy issues to consumers in a way that lets them make informed choices. A key part of that is to get a diverse set of perspectives as we’re building the product. I’m personally really excited about the project and the potential that it has for good.

If you’re interested, you can apply at the link above, or reply to this email if you have any questions about the role.

-main

Bozhidar has written about The Curious case of Clojure Contrib, with his perspective on Clojure Contrib. Alex Miller then wrote a response: The Completely Ordinary Case of Clojure Contrib. The comments on Reddit also had some good follow-up.
Those two posts were responding to this discussion around a new doc for clojure.org on Contrib libraries
I talked with Zach Tellman on The REPL about Elements of Clojure, his work in the Clojure community, the Clojure contribution process, and what’s next for him. I was glad to be able to talk to Zach, though it was a little bittersweet as he’s going to be less involved with Clojure in his new work at Microsoft. Alex Miller also made a comment in response on Reddit to some of the things we discussed.

If I was to re-record the podcast, I would clarify this comment which understated recent changes:

It doesn’t seem clear to me that any course corrections [to the way Clojure is developed] are coming either, that there’s going to be any difference, although I should point out Alex Miller’s weekly roundup of what he’s been working on with Clojure … I wouldn’t say nothing has changed

We’re definitely seeing greater clarity on things like Contrib, more of an insight into Clojure’s development process via Alex’s Inside Clojure blog, and are in the process of documenting more clearly the expectations of contributing to Clojure itself.
Tickets to Heart of Clojure are now available. This is shaping up to be a really cool event. I was also pleased to see Saskia Lindner and Bozhidar Batsov will be hosting it. I’d also note a stellar array of companies that are sponsoring Heart of Clojure. If you appreciate them sponsoring a community conference like this, consider contacting a couple of them to voice your appreciation.
Dutch Clojure Days videos are up now. There were also a few recaps of the event from different participants. They were a good read if like me, you couldn’t make it in person.
Clojure/north was last weekend. The videos aren’t up yet, but the keynote was from Jon Pither of JUXT, talking about Crux. Crux is a new bi-temporal database that lets you query against a valid time a.k.a business time, as well as the transaction time. They have a blog post talking more about bitemporality and showing how to use Crux. Disclosure: I was part of a private preview of Crux before it was released publicly.
Vouch is a “breakthrough blockchain-based identity and intelligence platform”. I don’t fully understand what that means, but they’ve got a stellar team of Clojurists on board including Ray McDermott, Mike Fikes, and David Nolen and are betting on ClojureScript heavily.

Libraries & Books.

defns is a library from Дејан Јосифовић, a reader of The REPL. It lets you define functions with inline spec definitions, and use the specs to create pre/post conditions on the function.
Sean Corfield continues to push forward with next.jdbc. If you’re a heavy user of clojure.java.jdbc, or write a library that uses it, now is the time to give your feedback on the API.
Of note to Transit users was this change softening the warnings about persisting Transit.
TechAscent continues to put out high quality libraries in the data science space. In February they announced tech.ml.dataset and tech.ml, but I only got to them recently.
Jacek Schae has updated his comparison and benchmarks of a bunch of different front-end JS frameworks.

Foundations.

There was a great discussion at the Mechanical Sympathy mailing list about triggering page faults in one thread ahead of the writing thread. Highly technical, and highly enjoyable.
Hannah Henderson wrote a widely shared post on her experience of micro-promotions and mentorship at CircleCI.

Tools.

ohmyclj is a Clojure script running tool.
The Clojurians Slack Log is not working at the moment, but Exoscale has sponsored credits to help it run, and there are some new people coming on board to help run it too.
Light Table has some new maintainers, and is working on upgrading from old versions of Electron and ClojureScript.
Bozhidar has an update on what he’s been working on recently.

Recent Developments.

Alex Miller talked more about how closed spec checking will work, and Clojure 1.10.1.
The Defn podcast talked with David Miller, the maintainer of Clojure CLR.

Learning

Learn about the secret fourth arity in the map transducer + Reddit. Reading this felt a little like stumbling into a secret area in a video game.

Misc.

Around the year 2030, 10 years 252 days and 10 hours away from now, we will be in a position where we set off an irreversible chain reaction beyond human control, that will most likely lead to the end of our civilisation as we know it. That is unless in that time, permanent and unprecedented changes in all aspects of society have taken place, including a reduction of CO2 emissions by at least 50%.

“You did not act in time” - Greta Thunberg

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

86: Lots to cover

Mon, 15 Apr 2019 21:30:13 +1300

Notes.

The last few weeks/months have been pretty busy for me. I’ve started a new job, released some libraries and I’m going to the USA for work in a few weeks!

I’ll be in San Francisco from 5th-11th May, and in New York 12th-17th May. If you’re going to be in either of those places at the same time and would like to meet up, reply to this email and we can try and arrange a time.

I’m looking to hire a part-time contractor to do some work on Deps. If you’re a reader of this newsletter, you’re clearly have fine taste and are very talented, so please take a look if you’re in the market for flexible, part-time Clojure work.

Lastly, a reader was kind enough to send me an Easter card a few weeks ago. I couldn’t make out their name on the postcard, but thanks to the sender!

-main

Dragan Djuric has been on a streak with writing his Deep Learning in Clojure from Scratch, part 0, part 1, part 2, and so many more parts that you should just go to part 0 for the index of all of the things he’s written.
What’s the point of Clojure? - a business approach from Magnet.
@scicloj has an online gathering very soon (< 24 hours from now) talking about Clojure and data science.
JUXT have a teaser page up for CRUX, their new bitemporal graph database. The bitemporal part is key here, it lets you separate transaction time (when you recorded it) from domain time (when the event happened). Often when you start an application these are the same thing. However, as you merge data from more sources, or backfill prior data, only having a transaction time can be cumbersome.
Replete is now available on iOS and Android.
clj-kondo is a new linter from Michiel Borkent that sparks joy. One especially neat thing is the IntelliJ integration, I think this is the first linter I’ve seen that has integration with IntelliJ.

Audio

I realised I hadn’t mentioned any of my podcast guests for the last few newsletters, so here they all are at once:

Clojure at Apple with David Taylor
Monorepos and monologues with Alex Engelberg
Editing and Formatting Clojure code with Shaun Lebron
Testing Clojure and ClojureScript with Arne Brasseur
Clojure MXNet with Carin Meier
Looking at Clojure with a business mindset with Jonathan Boston
Cursive IDE with Colin Fleming

Libraries & Books.

I put out re-frame-10x with some new features, especially subscription pinning and searching thanks to Shen Tian.
tilakone is an FSM library from the fine folks at Metosin.

People are worried about Types. ?

I released defn-spec, a library for defining fdef’s inline with your Clojure functions, and I guess this kinda qualifies as me worrying about types too. I also wrote a bit about my motivations for building the library.
How to parse custom defn macros with clojure.spec
Schema and select in spec-alpha2

Foundations.

Depending on your OpenJDK distribution, Java’s SecureRandom may use /dev/random (blocking) instead of /dev/urandom (non-blocking, and the correct device to use).

Tools.

Chlorine is a Clojure plugin for Atom
Thomas Heller on What shadow-cljs is and isn’t. This doubles as a good overview on how the ClojureScript compiler works.
Thomas Heller again on Code-Splitting ClojureScript
Thomas Heller once more for the trifecta, this time with his Patreon
How to run Clojure code quality tools with Sonarqube
The Emacs Package Developer’s Handbook
nREPL 0.6 is out

Recent Developments.

I’ve been enjoying all of Alex’s Inside Clojure post’s, but espeically interesting was the one on spec/select. I’m also very excited to see that closed schemas may be on the cards!

Misc.

I really enjoyed this post on building a robust log collection pipeline for Google Fiber’s monitoring of client router’s (not their content though) at customer’s houses.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

85: Surveying the landscape

Thu, 21 Feb 2019 21:41:42 +1300

-main

If you haven’t read Bozhidar’s post on the future of CIDER I’d urge you to do so.

I really think the work I’ve done (not to mention the great work others have done) is worth a bit more than this, and I hope that people are going to realize this before I decide to throw in the towel and call it quits.

If you use CIDER in your day job, think about supporting the Open Collective, either individually, or through your company. Since he wrote the post, annual donations have gone from $4k/year to $7k/year. Based on the most recent survey results, 46% of respondents use CIDER, so there is a lot of opportunity for us to grow that number. A few dollars each month is a small price to pay to ensure that CIDER continues to grow and be maintained.
The Clojure survey results are out. I analysed the free-form comments, and Alex Miller had a good follow-up on the comments.
Alternatives to Clojurians Slack.
Clojurists Together is funding Aleph and Neanderthal for the next three months.
Deep Learning in Clojure from Scratch to GPU - Part 0 - Why Bother?

Libraries & Books.

aerospike-clj is a new Clojure client for the Aerospike database
Sean Corfield has been doing some work on a new JDBC library.
Datascript has a new release out with significant performance improvements. Some of this work was funded by Clojurists Together.
js-interop looks like a really nice CLJS library for interoperating with JS objects. Be sure to read the motivation section to see how it compares to your other options.

Foundations.

We need more (Java) keywords, captain!
DIY Garbage Collector

Tools.

Bozhidar has written a bunch of other posts lately. Happy New CIDER, nREPL: Beyond Clojure, CIDER 0.20 (Oslo), and The Clojure Style Guide Redux.
Leiningen 2.9.0 is out
Writing awesome docstrings.
The future of Boot looks good.

Recent Developments.

Alex Miller has some updates on what he’s been working on: survey, spec, spec, clojure.main errors, spec, surveys, spec, spec, jdk regression, spec, sets, tools.deps.
CLJ-2484 has more details on the JDK performance regression.
ClojureScript 1.10.516 is out with a bunch of improvements, including better type inference, better performance, and porting Clojure 1.10’s error messages.

Misc.

Time Formatting and Storage Bugs ordered by year. Luckily, after 2019 we don’t have any serious classes of bugs coming until 2036.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

84: surveys, back buttons, and herbs

Wed, 09 Jan 2019 08:11:06 +1300

Notes.

I’ve been on holiday the last few weeks at the beach. It’s been nice to feel the sand between my toes and see my kids enjoy swimming in the lagoon. I’ve also got some good features on Deps finished, I’ll write more about them soon.

Lots of new releases this week, I suspect many people are taking advantage of the holidays to finish off projects.

-main

The annual State of Clojure survey is on now until 22 January. If you’re interested enough in Clojure to read this newsletter, you should definitely be filling out the survey.
Jonathan Boston’s best and worst Clojure code of 2018.
Jonathan Boston also with a good post on the recent language changes to JS and how CLJS has already solved those problems, in a better way.
And Jonathan Boston once more with how ClojureScript is not CoffeeScript.
Clojure/north 2019 is happening on April 19-20th in Toronto. I’m looking forward to Mike Fikes, Tommi Reiman, and Rafal Dittwald’s talks. The CFP is still open until February 1, so if you’d like to speak there, get on to it.
re-frame and the Back Button

Libraries & Books.

kixi.stats 0.5.0 is out, with a discussion of some new functions to help with doing ‘boring data science’, and doing everything with transducers.
Herb is a new CSS library for building UI components in ClojureScript, building on Garden. Top marks for the extensive documentation.
calfpath is a very flexible, new Ring routing library.
CLI-matic is a new CLI parsing tool for Clojure and works well with Graal.
expectations for clojure.test gives you expectations style assertions but with clojure.test compatibility.

Foundations.

A more literal foundation this week, the Software Freedom Conservancy is the fiscal sponsor of Clojars and Clojurists Together. They’re having their annual funding drive, and the next $15k of donations is matched dollar for dollar by a generous group of sponsors, including Elana Hashman. The SFC takes a small percentage of any money that Clojurists Together receives (~10% IIRC), but we are a very demanding project (lots of contracts to review, payments to make, questions to answer, e.t.c.), and require far more resources than we are contributing. We couldn’t have got to where we are without their support. I just signed up as a monthly supporter, and I’d encourage you to do so as well.

Tools.

Speaking of Elana, here is an update on updating Leiningen and Clojure versions before the next Debian freeze. It’s important and often thankless work, but I really appreciate it. I talked with Elana a few months ago about her work, if you’re interested in learning more about this.
Cider 0.19 (Raleigh) is out with improvements to the connection management system, and updates for Clojure 1.10’s error messages.
New releases of tools.deps and clj are out. Notably, the way to specify a classifier on an artifact is now groupId/artifactId$classifier.
How to get lein-test-refresh notifications when using Emacs inside a remote tmux session (!).
The EDN Query Language looks interesting, a bit of a hybrid between GraphQL and Datomic Pull queries.
If you want to give your security and ops teams a scare, talk to them about putting REPLs on your production deployments.
Using Graal on a small but real Clojure application
Nikita Prokopov has been working on Clojure syntax for Sublime Text 3.
Liquid is a new emacs inspired text editor, written and extensible in Clojure. You can use the editor inside any JVM based program, and use any JVM based library to extend the editor.
Floki is a JSON/EDN browser for the terminal.

Recent Developments.

Alex Miller continues his Inside Clojure journal

Learning

When to avoid with-redefs. I’ve definitely had some headscratching moments with with-redefs. Occasionally I run into situations where the redefed function doesn’t get replaced after the with-redefs scope has ended. If you’ve ever had this and figured out what the problem is, let me know.

Misc.

A thread of nice looking failures from test reporters.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

83: Happy New Year!

Tue, 01 Jan 2019 08:49:36 +1300

Notes.

Happy New Year! If you celebrated Christmas, I hope you had a great time. If you didn’t, I hope you had a nice break away from work.

-main

The biggest news of the last few weeks was that Clojure 1.10 was released. Lots of cool stuff here, and as always, a smooth upgrade path.
Yehonathan Sharvit welcomes Clojure 1.10
Over the last few weeks I’ve put The REPL’s entire back catalogue of newsletters online. I often found that I wanted to refer back to something I linked a while ago and had trouble finding it in my email. At some point I’m going to add some local site search so you can search for keywords, URLs, e.t.c., if you have any good experiences doing this, let me know what you found.
If you use Aleph, chime in on this thread which is compiling a list of users.
Arcadia (Clojure with the Unity game engine) has a beta out.
Steve Klabnik has some thoughts on Clojure’s stability
I talked with Antonio Monteiro about Lumo, GraphQL, and OCaml recently. It was a lot of fun and I learnt a lot.

Libraries & Books.

Dispacio is a predicate stack dispatch system for Clojure and ClojureScript. Think multimethods, but more flexible, and also with a bit more responsibility/risk for the user.
Three related libraries around Hiccupy Reagenty development: mr-clean is a Reagent compatible library without a dependency on React, Ikota is a Hiccup implementation for Clojure/ClojureScript, and Clojure Hiccup Page (CHP) is a PHP inspired Hiccup server-rendered templating library.
When I talked with Chris Nuernberger a few weeks ago about TVM CLJ, a big focus of the conversation was dealing with memory efficiently. He’s just published a post and library about tech.resource, their resource management library. I nearly used the term “off-heap” here, but the post has a good explanation of why other words might be less confusing. What is especially cool about this library is that you can use it with the JVM GC. You can set a stack based boundary where you know the memory will be deallocated at a certain point in the program, but it can also be deallocated sooner if the GC determines this is safe.

People are worried about Types. ?

respeced is a library for verifying spec fdefs.

Tools.

Dash.app now supports cljdoc, an offline documentation app.
depsviz can generate a Graphviz visualisation of your deps.edn or project.clj dependencies.

Recent Developments.

Alex Miller takes us Inside Clojure again. I’ve been really enjoying these posts. Also of note, longtime Clojure contributor Ghadi Shayban has joined Cognitect recently.
A list of all the tickets fixed in Clojure 1.10

Learning

Clojure is Capable shows how to build a FUSE filesystem in Clojure.
One experience report of a team using Om and moving to re-frame instead of Om.Next.

Misc.

Russ Olsen on the best programming advice he ever got.

If you’d like to support the work that I’m doing, consider signing up for a trial of Deps, a private, hosted, Maven Repository service that I run.

Thanks!

82: Formatting, coroutines, REBLs, new Clojure RCs

Sun, 16 Dec 2018 14:48:46 +1300

Notes.

There’s been a lot going on in the Clojure community in the last few weeks. There was another sprawling discussion about community involvement in the development of the Clojure language, and then the Conj came afterwards with a bunch of great talks. I want to give a special mention to Alex Miller and whoever else was involved with getting the talks up on YouTube so quickly. I wasn’t there, but I was still able to follow along virtually with not a lot of delay.

If you’ve enjoyed The REPL this year, either in podcast or newsletter form, please consider supporting me by signing up for a trial of Deps. Deps is a private, hosted, Maven repository service that I run. I enjoy writing and recording The REPL, but it does take me away from other paying work. If you or your company needs to share private Clojure dependencies and don’t want to have to run, patch, maintain, and backup your own Maven repository, take a look at signing up for Deps. If Deps isn’t a good fit for you, please let me know also, that’s really useful information.

Thanks!

-main

REBL is a new tool for exploring the data in Clojure programs from Cognitect. The release of this library and the accompanying talk explain the motivation for several recent additions to Clojure: datafy, nav, and extending protocols via metadata. REBL also has an interesting business model. Non-commercial use is free. For commercial use, Datomic customers get it as part of their Datomic license, or you can join the Cognitect Patreon to get a license to it.
For a long time I’ve wished that Clojure had something similar to gofmt, a source code formatter which defines a canonical and fairly strict set of formatting rules for Clojure. I wrote up a proposal for such a formatting spec and tool on ClojureVerse. Nikita Prokopov came up with a proposal for one possible set of formatting rules. There’s also a GitHub repo with more detailed discussions on the different possible formatting rules.
I wrote about how to upgrade your Clojure projects to Java 11 on the Deps blog.
Tim Baldridge on contributing to Clojure
Open Source is Not About You by Rich Hickey.

Libraries & Books.

cloroutine is a generic, macro-based, stackless coroutine builder for Clojure and ClojureScript. The author also has a great announcement post on ClojureVerse talking about the motivations and architecture. It’s in a similar niche to xodarap which I mentioned in my last newsletter. The difference is that where xodarap uses core.async, cloroutine takes inspiration from core.async and rewrites functions in a similar manner to the core.async go macro.
Get Programming with Clojure is a new book from Yehonathan Sharvit (Creator of Klipse), in pre-release at Manning.

People are worried about Types. ?

On a recent podcast with Martin Klepsch, we were talking about Hoogle, the search engine for Haskell that lets you search by type signature. We wondered whether something similar would be possible for Clojure. Michael Borkient took this idea and created re-find. You can type input arguments and expected results or predicates and it will show you a list of functions which fit the parameters. It’s hard to explain the experience of using it, I recommend trying it out.
Sean Corfield writes about nil, NULL, and optionality in the context of SQL and clojure.java.jdbc.

Foundations.

Open JDK startup times from 8 through 11.

Tools.

Leiningen 2.8.2 and 2.8.3 were recently released. 2.8.3 is a hotfix release for some bugs that were introduced in 2.8.2.
emidje is an Emacs test runner for Midje.
The recent Day of Datomic Cloud training session was recorded and is available for free on YouTube.
If you can’t wait for AWS to add support for Java 11, you can use Ghadi Shayban’s new AWS Lambda Custom Runtime.
Configuring zprint

Recent Developments.

Clojure is nearing release, 1.10.0-RC5 is out.
Alex Miller has a great update on what he’s been working on with Clojure in the last week.

Learning

Tom McTighe had a great talk at Clojure eXchange about applying Clojure’s design principles to it’s documentation. Here’s a sketch of some of the ideas in the talk.
There’s also a roundup of all of the Clojure eXchange talks from Solita.

Misc.

One perspective from BloombergNEF about preparing for a low carbon world. I sometimes avoid looking at climate change related news because it can feel so paralysing. This was a good overview of both the looming challenges, and some bright spots, particularly around solar and wind generation.

81: Giving thanks

Fri, 23 Nov 2018 10:34:58 +1300

Notes.

I’m not an American, but I do appreciate the opportunity one day a year (at least!) to spend some time thinking about what I’m thankful for. In the sphere of Clojure, this year I’m thankful for:

All of the Clojure community and core team continuing to build a great ecosystem and language
Day8 and Mike Thompson for employing me and funding me to work on the re-frame suite of tools and libraries (along with other internal work).
Clojurists Together members, you’re all the reason that Clojurists Together has any money to fund any work.
Everyone who applied for funding from Clojurists Together. We weren’t able to fund everyone, but I really appreciate the effort that went into submitting an application.
All of the projects that we were able to fund and the amazing work they did. You can see them on one page here.
The Software Freedom Conservancy (SFC), we don’t talk about it too much (we should do more), but the SFC have put in a lot of time into Clojurists Together this year helping us get up and running. They do lots of good work for us and other OSS projects, consider becoming a supporter.
Everyone who is a customer of Deps.
Lastly, all of you for reading this newsletter and listening to The REPL podcast, sending me feedback, and letting me know about cool projects.

-main

A new Clojure podcast: Functional Design in Clojure. I just found this as I was preparing the newsletter, but I’m looking forward to listening to these.
Writing testable CLJS apps with re-frame and devcards
clj-templates is a search tool for Lein and Boot templates
It was my pleasure to talk with Elana Hashman, Hannah Henderson, and Howard Lewis Ship on The REPL. I also wrote a (very late) announcement post about The REPL.
Probably not ideally timed given the Thanksgiving holiday, but there was some more discussion about Clojure and the openness of its development process. It started with the release of Clojure 1.10.0-beta8 which introduced a new function async-require. This is not an asynchronous require call, but the opposite, a require that is safe to run in an asynchronous context. Some people found this confusing, but Alex Miller wasn’t interested in discussing it further. That then spilled over onto Twitter with more discussion about the Clojure development process.

Libraries & Books.

xodarap lets you recurse without worrying about blowing stack boundaries. Under the covers it uses core.async.
tvm-clj is a new high-performance numerics compiler. This is super interesting and opens up a lot of new areas that Clojure can tackle around high-performance code, dealing with unsigned types, numerics, and machine learning.

People are worried about Types. ?

Clojure Spec-Alpha2 has a GitHub repo, but there’s not much news about what will be changing yet.
Elsa is a new static analysis library for Emacs. This issue talks about converting the Haskell inspired type annotations into Lispy ones.
The Road to Typed Clojure 1.0

Foundations.

Amazon has come out with Corretto, a new OpenJDK distribution. Notably, Java 8 support will be provided until at least June 2023 (Oracle’s JDK is ending free updates for commercial users in January 2019). For Linux distributions they only provide RPM’s, but hopefully, they will also provide Debian packages.
Bifurcan is a new set of functional data structures for the JVM. They comparevery favourably to mutable data structures, especially at large collection sizes.

Tools.

Reid McKenzie gave a great talk on Katamari, a new build tool he’s making, along with an excellent survey of build tools in general. I learnt a lot from this talk, it’s highly recommended.
zprint-mode.el is an Emacs minor mode for formatting your code with zprint.

Recent Developments.

ClojureScript 1.10.439 is out with a bunch of improvements. Notably, compiler performance is much better.

Learning.

A guide to logging in Java, but a lot of this carries over to Clojure too

Misc.

Bill Gates plans for fighting climate change

I’ve got quite a backlog of interesting links that I wasn’t able to include here, sorry if I missed your great project or post.

80: Datafy, paren parties, and adopting a neanderthal (function)

Wed, 24 Oct 2018 09:33:37 +1300

Notes.

Hoo boy.

There was quite a commotion this weekend after Stu Halloway’s appearance on the Apropos podcast. A few years ago there was a similar commotion and I wrote this on HN with my perspective. I think it is still accurate today.

The thing to realise about Clojure is that it isn’t an open source language like Python. It is a language controlled very tightly by Rich Hickey and Cognitect. Major work is done in secret (transducers, reducers, spec), then announced to the world as a “Here it is!” and then suggestions are taken. This goes well mostly, though it took a lot of outside persuasion that Feature Expressions weren’t the best idea, and to come up with Reader Conditionals instead.

The underlying problem Clojure/Core has is their communication. If they would come out and explain their philosophy then people wouldn’t get frustrated and confused when they expect the language development to work like other open source projects. Clojure’s development is functioning exactly as planned. It’s not a mistake.

A better way to treat Clojure is closer to a project at Apple (except for Swift). You can submit bugs, and make suggestions for future improvements, and if you really want to provide a patch. But go into it realising that it’s not a community project, and you’re much less likely to get frustrated.

With all that said, the proof of the pudding is in the eating, and for the most partClojure has developed pretty well from Rich’s tight control. I’d love it if there was a Snow Leopard year for Clojure where the focus was fixing longstanding bugs and feature requests, and more focus on those in general, but the language is developing well.

While I can’t claim to speak for the community, in my experience with the Clojure folk I talk with, the concerns Zach Tellman, Tim Baldridge, Bruce Hauman, and others raised in the resulting Twitter threads are shared by more than a tiny minority of the Clojure community. On the whole, I think Clojure is developing well, but there are opportunities within the Clojure language, and for supporting tools, documentation, and libraries to continue to improve the Clojure experience.

-main

Snyk released very curious results in a survey on the JVM ecosystem last week. The most surprising thing about it was the question about the principal JVM language that people used. Java was first with 90% share, but Clojure was second with 3%, Kotlin at 2.4%, Groovy at 2.4%, and Scala at 1.8%. I was very surprised to see Clojure ahead of Scala, in my experience, Scala has been 4-5x larger than Clojure in terms of jobs, adoption, e.t.c. There were 10k respondents to the survey though, so it seems like a reasonable sample size, and the way the survey was distributed doesn’t seem too biased. Other people also found that surprising.

Another curious thing about the survey was that 60% of respondents used Java EE. I have no experience with Java EE, or that ecosystem, but I was surprised to see it so highly represented. Maybe that is the case though?
Clojurists Together is funding Datascript and Kaocha this quarter
Datomic On-Prem has a new caching option to use SSD’s
How Miika Koskinen uses tap>, and the libraries he recommends
I had a timely discussion with Ben Brinckerhoff about spec and error messages
It was mentioned above, but the Apropos discussion with Stu Halloway is a really good insight into how Clojure is developed, and how the Clojure team thinks about problems.

Libraries & Books.

Bunnicula is a new library for asynchronous messaging with RabbitMQ, with a great writeup on the motivations and context.
You can adopt a function from Neanderthal
Giving new life to existing OM legacy SPAs with re-om

People are worried about Types. ?

A beginner’s FAQ for Clojure.Spec, though I think this is useful for everyone

Foundations.

Sharp Tools

Tools.

Using JMH with Clojure. JMH has been on my radar for a while but I didn’t have a good understanding of how to set up a JMH benchmark with Clojure. Now I do.
nREPL’s Secret TTY Transport
An update on Hyperfiddle

Recent Developments.

Since my last email, Clojure went to a release candidate, then back to beta with a brand new datafy namespace.
CLJ-2373 is where work on improvements to exception messages and printing has gone

Learning.

A good write-up of an internship at JUXT.
A model of interceptors

Misc.

Enjoy a Paren Party
I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like Pitch, JUXT, Metosin, Adgoji, and Funding Circle) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

79: Party REPLs and a new Clojure beta

Tue, 09 Oct 2018 10:19:28 +1300

Notes.

I’ve been digging up my driveway to turn it into more grass. It’s been fun using heavy machinery to move the dirt around and seeing a tangible result of my work. Often in software, we don’t get that tangibility, and I definitely don’t have sore muscles the next day!

-main

Apache MXNet 1.3 is out with experimental Clojure bindings
Clojurists Together has a Call For Proposals open until midnight October 9th PST. I’m struggling with the timezone math, but that’s in the next day or so.
I talked with Nikita Prokopov on The REPL about Datascript, Rum, Fira Code, and lots more.
Polylith is a new architecture/design pattern. It’s demonstrated with Clojure, but isn’t really Clojure specific. I haven’t fully digested it, but it looks ambitious and is worth a read.
A Year in Clojure is a good experience report of Clojure coming from an F# background.
Martin Klepsch on documenting the Clojure ecosystem

Libraries & Books.

Duct scheduler.simple is a… well you can probably guess.
cond-let merges cond with let

People are worried about Types. ?

and Stripe is building a typechecker for Ruby

Foundations.

Salvatore Sanfilippo on software code comments. This goes far deeper than the often simplistic suggestion of “code comments should explain why it’s doing something, not what it’s doing”. He categorises the comments in Redis into nine categories with good examples.
Open JDK has changed the layout of their macOS tarballs to be more compatible with Homebrew.
There is a proposal to let people disable the JDK Security Manager. This would let the JVM optimise a bunch of code that currently checks for a security manager at runtime. See Sean Mullan’s tweet for a little more detail.

Tools.

clojure-party-repl is an Atom package for pair programming with a party REPL
Hyperfiddle is a low/no-code development platform that sits on top of Datomic.

Recent Developments.

Clojure 1.10.0-beta 1 is now available, the first in the beta series.
CLJ-2374 fixes a Clojure build issue with JDK 11. You would be unlikely to hit this when running Clojure applications normally, as the Clojure JAR is AOT’d

Misc.

Here’s a tour of Reaktor’s Helsinki offices. ClojuTRE conference goers got to go for a tour through here. It looks like a pretty nice place to work, I don’t think I’ve ever seen an office with a built-in sauna.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like JUXT, Metosin, Adgoji, and Funding Circle) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

78: Ions, Dhall, new clj-new

Wed, 19 Sep 2018 02:14:26 +1300

-main

Rich Hickey on Datomic Ions at Clojure/nyc
This week on The REPL I talked with Mike Fikes about ClojureScript type inference, Graal, and his work on Clojurists Together.

Libraries & Books.

Kaocha is a new test runner from Lambda Island with a bunch of nice features including test randomization, fail fast, and profiling slow tests. There’s also some nice docs on cljdoc.
dhall -clj lets you consume Dhall expressions from Clojure. Dhall is a very Haskelly looking non-turing complete language, suited for writing config, templates, e.t.c.

People are worried about Types. ?

But Ambrose Bonnaire-Sergeant is proposing to do a thesis on automatically generating Typed Clojure annotations and specs.

Foundations.

Did you know there are two reasons you can get a NoClassDefFoundError on the JVM? And that one of them can happen when the class is present?
ClojuTRE was last week and Jan Stępień had a talk on building native binaries with Graal. The slides are up here, and the talk is already out.

Tools.

clj-new has a new version out: 21ca1b27f46dc324be084ba839beca555aeda387. Not sure how I feel about SHA’s as the new version number.

Learning.

I’ve mentioned Heart of Clojure before here, a new Clojure conference. They’re now looking for sponsors for their first event next year.
Lambda Island has some new screencasts on data science using kixi .stats from Mastodon C

Misc.

Make sure you’re not drinking anything when you read Just JUXT #34. I won’t spoil it for you here.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like JUXT and Metosin) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

77: Specmonstah, podcast episode 2, and error messages

Mon, 10 Sep 2018 22:54:25 +1300

Notes.

Thanks to everybody who has subscribed to The REPL podcast so far, the first episode with Michael Drogalis was very well received. I’ve got a bunch of great guests lined up for the coming weeks.

-main

Next up on The REPL podcast, I talked to Daniel Higginbotham about Specmonstah, Clojure Spec, and his Clojure/Conj talk proposal.
People’s favourite macros

Libraries & Books.

specmonstah (mentioned above also) is a library for automatically generating fixtures with complex domain
nREPL 0.4.5 has been released

People are worried about Types. ?

Clojure 1.10-alpha7 is out with some improvements to error messages
Is The Little Typer the static typing book I’ve been waiting for?
“Not having a thing is not the same as having an empty maybe-thing”

Foundations.

A side-by-side reference to Common Lisp, Racket, Clojure, and Emacs Lisp
The Z Garbage Collector coming in Java 11 looks very exciting
Java is still available at zero cost
The history of Lisp

Tools.

Sayid is now part of the Clojure Emacs GitHub group
CIDER 0.18 is out with a lot of new features and changes. I’m really proud that some of this work was able to be sponsored by Clojurists Together members.
A new high level diagram of CIDER’s architecture from Mikhail Gusarov..
Figwheel Main has some neat new zero-config auto-testing features. I have spent many hours building up a config to test ClojureScript projects with Karma, and it looks like I’ll be able to throw it all away and replace it with this.
Workspaces from Nubank is a library/tool to help you develop UI components, similar to devcards.

Recent Developments.

Some comments from Alex Miller on Java 10+ and Clojure
CLJ-1279 (“Wrong number of args (-2) passed to…”) has been fixed in the recent Clojure alpha release
Mike Fikes has been doing some really interesting work on type inference for the ClojureScript compiler. This can create smaller, faster code. Check out his Twitter account for some of the experiments he’s been working on, as well as some tickets in JIRA like CLJS-2865.
Mike Fikes also has created some CLJS performance benchmarks showing big speedups (2x) over a large corpus of code. Smaller real-world projects may not quite achieve this speedup.

Misc.

I read a blog post from a fellow Kiwi who has been living with a zero-waste life, i.e. avoiding the creation of any waste, not just recycling it. I read it a few weeks ago, and it has been on my mind, and really affected the way that I look at food packaging, consumer culture, and how much waste that I produce.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like JUXT, Metosin, and Status) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

76: The REPL podcast, all juxt all the time, and peeking behind the serverless curtain

Thu, 30 Aug 2018 10:37:39 +1300

Notes.

The big news this week for me is that I’m launching The REPL podcast! The podcast is a companion to this newsletter where we can go in-depth on some of the technical details behind the Clojure programs and libraries you use every day. The first episode is with Michael Drogalis where we talk about Pyrostore’s recent acquisition by Confluent, the future of stream processing, the future of Onyx, and data-oriented design. It’ll be up on iTunes in the next few days, in the meantime, there’s a link to the RSS feed on the website.

**I’ve resent this newsletter as I made a mistake in the note below about David Nolen working with Suiteness.

-main**

Late breaking news just before I hit send, David Nolen is working with Suiteness via a consulting position at Cognitect. In my haste to send the previous version of this newsletter I overlooked that this was a consulting position, and said that he had joined Suiteness. Sorry for the misinformation.
Datomic just announced Ion Parameters which lets you pull configuration from AWS Systems Manager Parameter store. You could also read parameters from AWS Secrets Manager with their recent integration.
Just Juxt is a new blog series focusing on all of the things you can do with juxt
Mike Fikes on the Two-File ClojureScript Namespace Pattern. I’ve used this pattern quite a bit with macro code; it’ll be good to be able to point people towards this full explanation of what’s going on.

Libraries & Books.

Imitating Scala Futures with Go channels (in Go and Clojure core.async)

People are worried about Types. ?

Some good tips from Conan Cook on using spec, from your REPL sessions, through to ClojureScript, re-frame, and Datomic
Eric Normand reflects more on Rich Hickey’s most recent keynote on spec
Spec error messages look like they will continue to improve in new Clojure releases

Foundations.

Steve Losh on a road to Common Lisp
After stagnating for quite a while, recently years Java has been doing well at keeping up with new TLS developments. JEP 332 adds support for the recently finalised TLS 1.3 and is targeted for JDK 11.

Tools.

Setting up ClojureScript, IntelliJ IDEA and Shadow CLJS
clj-refactor has a new release compatible with new versions of CIDER and Java 10
How to call Kotlin from Clojure
An experience report on making an iOS app with ClojureScript and React Native
If you can’t get enough Emacs on your computer, you can also listen to the EmacsCast

Recent Developments.

Mike Fikes has been doing some interesting work on type inference for the ClojureScript compiler. CLJS-2865 optimises string concatenation and can give a moderate to large speed-up under string heavy workloads. CLJS-2869improves inference for cljs.core/and and cljs.core/or.

Misc.

I learnt a lot about different serverless platforms from a paper P eeking Behind the Curtain; I hadn’t realised that AWS Lambda doesn’t run functions from different accounts on the same VM. Well worth checking out to see what is going on underneath AWS Lambda, Google Cloud Functions, and Azure Functions.

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like JUXT, Metosin, and Status) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

75: Superpowers, magnets, and Apples

Thu, 09 Aug 2018 08:55:05 +1300

Notes.

It’s starting to warm up again in New Zealand. I’ve enjoyed not having frozen toes in the morning. Bring on spring.

-main

Congratulations to Michael Drogalis and Lucas Bradstreet, on Distributed Masonry (Onyx) being acquired by Confluent. Pyrostore’s infinite Kafka retention was a smart take on a hard problem.
Clojurists Together is funding cljdoc and Shadow CLJS for the next three months. I’m looking forward to seeing what they come up with.
Apple has a job open for a developer to build a new machine learning DSL in Clojure, with a focus on low-level JVM optimisation. It looks like a pretty unique job.
Magnet has published the Docker images they are using for MXNet machine learning with Clojure.
Eric Normand on the primary superpower of functional programmers

People are worried about Types. ?

But TypeScript continues to work on improving error messages.

Foundations.

See which JDK10 methods have intrinsics defined
JDK 11 early-access builds are out now
Java’s Magic Sauce gives a brief history of sun.misc.Unsafe
Hands-on with Java 11’s constantdynamic. The post talks about improving lazy idioms as one possible use-case,

Tools.

Not Clojure specific (yet), but Elsa is a new Emacs static analyzer
CIDER has a new website
Moving to Figwheel Main. Clojurists Together sponsored some of this work, and I’m pleased to see people taking advantage of it.

Recent Developments.

Clojure has bumped it’s ASM version
CLJS-1997 adds outward function type hint propagation. This patch should let function type hints flow further and require less manual hinting.
Stuart Halloway is going to be talking about how the Clojure community etiquette guidelines contribute to Clojure’s stability and suitability.

Learning.

ClojuTRE 2018 will be September 13-14th in Helsinki, Finland. Free for students, 50€ for others.
Heart of Clojure is a new conference coming next year on August 2-3rd 2019by Arne Brasseur and Martin Klepsch.

Misc.

“By now, you’re touring with Aerosmith and throwing Matisse paintings from hotel room windows, because when you order two Matisse paintings from room service and you get three, that equation is going to be balanced.” - James Mickens, The Slow Winter

I’m Daniel Compton. I maintain public Maven repositories at Clojars, private ones at Deps, and help fund OSS Clojure projects (along with tons of generous members like JUXT, Metosin, and Status) at Clojurists Together. If you’ve enjoyed reading this, tell your friends to sign up at therepl.net, or post a link in your company chatroom. If you’ve seen (or published) a blog post, library, or anything else Clojure/JVM related please reply to this to let me know about it.

74: Spec error messages, cronuts, and a boot

Sat, 28 Jul 2018 14:30:00 +1300

Notes.

Another long time between newsletters. Things have been quite busy lately in the Compton household with sick children, sick parents, and lots going on with Clojurists Together. Things seem to be settling back into a smoother rhythm though.

-main

Stuart Sierra continues his popular Clojure style guide series with Threading with Style
DataScript as a Lingua Franca for domain modelling
I wrote about the good, bad, and ugly of Google Cloud Platform, contrasting it with AWS.
How King uses Clojure to build a game editor
Clojurists Together June monthly update from CIDER and ClojureScript

Libraries & Books.

Incanter has a new version out
Cronut is a scheduling library, built around quartz from fellow Kiwi Derek Troy-West

People are worried about Types. ?

Ghostwheel is a spec omnibus library, including inline function specs (which are sorely needed in spec)
Clojure’s native error messages seem to be getting a overhaul in CLJ-2373, the output looks a lot better and much less verbose.

Tools.

Boot 2.8.0 and 2.8.1 are out
A good dive into compiling Clojure apps with Graal
C Reader for the Next Thousand Lisps is a Clojure reader in C, designed for you to build your own lisp with Clojure syntax.
Light Table is seeking new maintainers
Thomas Heller (shadow-cljs creator) on Why not Webpack?
I wrote a guide on testing against multiple JVMs on Travis CI

Recent Developments.

Clojure 1.10.0-alpha5 is raising the minimum Java version to 8

Learning.

Jacek Schae has created a course on Learning Reagent
Clojure/conj 2018 tickets are now on sale, and there is an open call for proposals. Durham looks nice!

Misc.

and now for something completely different, I really enjoyed The Secret to Love is just Kindness.

73: Pants, Ions

Thu, 07 Jun 2018 21:38:09 +1300

Notes.

It’s been a busy month or so with travel to family, but The REPL is back this week.

-main

Datomic has released a new feature: Ions. This is a way to run functions on your Datomic Cloud cluster.
I’ve been really excited to follow cljdoc, a new Clojure documentation project

Libraries & Books.

Zach Tellman talks more about his Elements of Clojure book
nREPL has completed its migration to a new project on GitHub

People are worried about Types. ?

Robust Clojure: The best way to handle nil, and HN comments

Foundations.

Oracle plans to disable risky Java object serialisation in the future
Java Mission Control was recently open sourced, but sadly most of the team was laid off last week.

Tools.

Lexikon lets you manipulate and replay your lexical environment, similarly to scope-capture
crossclj is now open source
Reid McKenzie on Pants, Bazel, and Clojure cross project builds

Recent Developments.

CLJ-2350: Improve error message when calling a keyword with the wrong number of arguments

Learning.

Zach Tellman’s Clojure SYNC talk is up now
The final Tellman link: Is = fast in Clojure?
Building a datalog

Misc.

CHECK_RARE and making sense of unusual occurences. This was a neat post. I like the idea of using something one step above asserts for things that should be extremely rare, but can occasionally occur.

72: varargs, Java 10

Sat, 05 May 2018 14:43:08 +1300

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When to use varargs
Clojurists Together April 2018 update is out, with the final updates from clj-http and Figwheel. Both projects have done really great work.
Rich Hickey was on the CaSE podcast and talked about some updates coming to Codeq.
The devil is in the details with Clojure discusses some issues that arise in larger Clojure codebases, and some possible solutions.

Libraries & Books.

Spy is a spy/stub/mocking library

People are worried about Types. ?

But this week they are too excited about Graal to talk about it.

Foundations.

Why Functional Programming Matters, translated to Clojure in the Maria cloud editor
There’s an interesting chart showing Java and Clojure release lifetimes on a discussion of Java 10.
Apropos has a discussion of Graal
A discussion of Python startup time and it’s implications on large systems and programs

Tools.

cljfmt-graalvm compiles cljfmt to a native binary. This improves startup time dramatically. More discussion on reddit
Top 10 things to do with GraalVM, from the GraalVM team
First impressions of GraalVM
Me on what’s new in Leiningen 2.8.0 and 2.8.1
Reid McKenzie has got early support for rendering images and MIME data in a CIDER REPL
lein-tools-deps lets you use a deps.edn file in your Leiningen project. Very cool.
tools.deps also has a new feature coming to add libraries at runtime
Some great Clojure testing links
Java Mission Control is being open sourced.
Stu displays your ClojureScript build size to let you find out where the volume is coming from. It has a bunch of very cool features to let you track changes over time, and see code size pre/post Closure compilation and GZIP compression.

Learning.

Robert Stuttaford continues his bridge diary

71: Reagent, Clojure over Haskell

Fri, 27 Apr 2018 21:14:07 +1300

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Clojurists Together is going to fund CIDER and ClojureScript from May-July. I’m really excited to see the work they can do. clj-http and Figwheel are finishing up at the end of April, and have done really great work.
Carin Meier shows how to use Graal with Clojure to be able to call R and Python
There’s a roadmap for Scala 3 out now. I always find it interesting to see what our JVM brethren are up to.

Libraries & Books.

Reagent 0.8.0 is out, with support for React 16.
http-kit 2.3.0 is out with a bunch of new stuff.
re-pressed is a clojurescript library that handles keyboard events for re-frame applications.
defn-spec provides a defn for spec

People are worried about Types. ?

Why do you prefer Clojure over Haskell?
Promenade is a newish Clojure library that lets you do monadish things
How to merge recursive specs

Foundations.

Tim Baldridge has a good explanation of the GraalVM and associated technologies, and the tradeoffs it would bring for a Clojure implementation.

Tools.

Clojure friendly mode with rebel-readline and expound.
Easier Clojure releases without commits

Recent Developments

CLJS–1627 jsdoc parsing fails to recognize union types, breaking resolution

70: Clojurists Together, defn

Wed, 18 Apr 2018 19:45:05 +1300

Notes

The first three months of Clojurists Together funding for clj-http and Figwheel are coming to a close, and we’re looking for projects to fund for the next three months. We’ve published survey results on the kinds of projects our memebers are looking to support and a call for proposals. Applications close on 22 April. Please reach out to the libraries and projects that you rely on and encourage them to apply for funding.

If you’re a sponsor of Clojurists Together, thanks heaps for your support!

I’m trying out different formats and email providers for this newsletter, let me know if you have any thoughts on the changes.

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Mike Thompson at Day8 was interviewed about re-frame on Defn.
Java arrays and unchecked math from Clojure Goes Fast
More discussion of Clojure startup time and making it faster

Libraries & Books.

Create your doppelgänger with test-doubles, a spying and stubbing library for Clojure/ClojureScript.

People are worried about Types.

Ambrose Bonnaire-Sergeant with probably the most perfect title for this section ever: Are unsound type systems wrong?

Foundations.

Symbolic Execution: Intuition and Implementation
Detroit is a new OpenJDK project to use the Chrome V8 JavaScript engine within Java.

Tools.

Dustin Getz has a Datomic FAQ
lein-nsorg is a leiningen plugin for reorganizing ns forms

Learning.

How is it functional to side effect globally in re-frame with the reg-* API?

Misc.

“What do you get when you combine a really crappy Mario clone, with an even crappier clone of the Donkey Kong theme song? Well if your answer is lawsuits you might be right but it’s for a good cause.” (ClojureScript audio in the browser)

69: prepls, flyovers, and tea time

Fri, 06 Apr 2018 09:58:47 +1300

Notes

This week’s newsletter is a bit late because I’ve been working on getting re-frame-10x 0.3.1 out the door. It’s got some very cool new features, check it out if you use re-frame.

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clojure.org has a new guide on higher order functions
Fly over Amsterdam with ClojureScript
Ethereum’s Compact Merkle Trie in Clojure (Part I, Part II)
I was interviewed on the Cognicast about Clojurists Together, this newsletter, Deps, and re-frame-10x.

Libraries & Books.

Walkable is a new library that lets you make SQL queries using Datomic pull syntax and define your schema in EDN.
Schematic is a new library for configuring Components. I’m loving the open source stuff coming out of Walmart Labs.
Do some fastmath with Java primitives
tea-time is a new task scheduler library from Kyle Kingsbury, taken from Riemann

People are worried about Types. ?

Ambrose Bonnaire-Sergeant on creating Automatic Annotation Tools
Gary Bernhardt with a clear discussion of Types for anyone who knows a programming language.
CLJ-2271 would enable Expound’s experimental macro errors to look even better.

Tools.

Datomic had a remote code execution bug for people running dev or free storage. If you haven’t already, you should update ASAP.
Lumo - Brightening the horizon for ClojureScript
Command line scripting with ClojureScript
Edge is a great sample project from JUXT to get you up and running with a full Clojure app without weeks of work. Malcolm Sparks has a new talk about Edge and the new generation of Clojure tooling.
Optimized Optimus Asset Paths from ClojureScript
Parallelizing a ClojureScript test suite
Calva: Clojure for Visual Studio Code
Such a genius idea, test-reporting (also from Walmart Labs) lets you see more context about a test failure. I’ve come up with various workarounds to get more context when assertions fail, but this looks like a much better option.

Recent Developments.

Hints about prepl keep dropping
The new CLJS Shared AOT cache will speed things up compilation times, but before you turn it on, check that your dependencies macro expansions are cachable. This means not reaching out to the environment or ClojureScript build config (other than through Closure defines).

Learning.

Learning kee-frame in 5 minutes, and putting the URL in charge
Transducer composition
7 Falsehoods Programmers Believe about Time & Place from Clojure SYNC

Misc.

Learn this one weird destructuring trick, and a bunch more

68: Accessible types, depot, and ClojureScript 1.10

Wed, 28 Mar 2018 12:32:49 +1300

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ClojureScript 1.10.238 is out and the clojurescript.org website has a good rundown of the changes
Jacek Schae has started a series on Medium distilling the Clojure style guide
A Resilient Git Dependency Algorithm
I’ve written up a summary of this years Clojure survey comments with some commentary. This is the third year I’ve done it, so it’s interesting (but a little worrying) to start seeing some of the trends.
Renzo Borgatti has also picked out some comments from the Clojure Survey

Libraries & Books.

ventas-bidi-syntax gives you human optimised bidi routes
Cambium structured logging 0.9.2 is out

People are worried about Types. ?

This proposal for improving the text to speech accessibility of Scala types is interesting.
Generating Kafka log schemas using spec-provider

Foundations.

Java 10 continues to improve behaviour in Docker containers
Java long term support

Tools.

I’ve been working on re-frame-10x and we recently released version 0.3.0. This release includes form level code tracing. If you use re-frame, I recommend you take a look.
Val Waeselynck has an excellent guide out on Programming at the REPL
Depot helps you find new versions of your deps.edn dependencies
I wrote about how to serve ClojureScript files in development without caching bugs

Recent Developments.

CLJS-2495: Closure compilation errors should stop CLJS compilation has been fixed

Learning.

Guide to ClojureScript namespaces
Did you know ClojureScript has a JavaScript API? Now you do.

67: Clojure survey, macrology, Elements of Clojure

Tue, 20 Mar 2018 20:53:52 +1300

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The State of Clojure 2018 survey results are out now. Worth reading to see where the community is at.
Eric Normand on What Clojure Needs to Grow + Reddit discussion
Data mining Clojars for Java 9 compatibility issues
The logging bear trap
Macros, meta, and logging with some clever macrology from Howard Lewis Ship

Libraries & Books.

Zach Tellman has finished a complete draft of his book Elements of Clojure. He’s also doing an AMA on ClojureVerse next week. Chas Emerick (among many others) has high praise for it:
“This is a great book that uses Clojure as the medium to explore some of the essential questions in computing, and maybe some ways to find an answer or two.
Zach has one of the sharpest minds I’ve ever encountered. You’d do well to soak this up.”
I’m a bit late on this, but Sean Corfield has taken over maintenance of core.cache and core.memoize and both have new releases out.
Kapok is a new lisp on the Erlang VM
Piggieback is seeing some new activity from Bruce Hauman and Bozhidar Batsov
Confuse is a library for machine learning classification metrics

People are worried about Types. ?

Are there any libraries that make clojure.spec less verbose?
I agree with Tim Gilbert and Tim Baldridge that Clojure’s error messages have gotten worse with the introduction of spec.
Expound has experimental support for providing suggestions to correct syntactic errors in macros.

Recent Developments.

Algebra of compatibility in test.check, and how Clojure does deprecations
CLJS-1439 has been fixed, it adds type annotations for goon-define vars

Learning.

A video from Clojure SYNC is out: Revenge of the Pragmatists
Guess My Number with maria.cloud
An experience report for hiring Clojure developers

Misc.

rachelbythebay is one of my favourite personal blogs, along with Programming in the 21st Century (RIP). Here’s a good war story of troubleshooting IPv6 issues.

66: object memory meters, flex box, and scope creep

Wed, 14 Mar 2018 21:36:00 +1300

-main

One-box stream processing with CSP
Guildsman Scope Creep
Stateless transient flags and some notes on CHAMP hash maps from Christopher Grande

Libraries & Books.

denisovans is a library that adapts neanderthal to be a core.matrix backend
kee-frame - re-frame with batteries included

People are worried about Types. ?

A new library for coercing from specs
Some nice error messages from the Urn lisp

Foundations.

Raw string literals proposal for Java. I’ve long wished for something like this in Clojure.
In many ways, React is now a foundation to much of the ClojureScript ecosystem. Here’s a sneak peek of what’s coming after React 16 with improvements for slower network connections and slower devices.
JDBC Next is a new API being developed to allow asynchronous access to databases
A very interesting critique of Scala, worth reading to see where Clojure could also improve

Tools.

An overview of the nREPL
depstar is a clj based (clj the tool, not clj the language or clj the file extension) uberjarrer
object memory meter is a very cool tool that lets you find out how much memory an object/data structure is using.
Lightning fast testing for ClojureScript React components
Content defined dependency shading

Recent Developments.

TDEPS-9 is a ticket for adding authentication to Maven repositories to tools.deps.alpha

Learning.

Robert Stuttaford’s dev diary building a Datomic app for ClojureBridge
12 things learned from evangelizing Clojure at work

Misc.

Why not Flexbox? by Kevin Lynagh

65: Redux, looking graphs, apropos

Tue, 06 Mar 2018 18:30:15 +1300

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Clojurists Together has the February update out. Bruce Hauman and Lee Hinman have been doing some really great work. We’ve also had a bunch of new signups since the post came out which is also great.
Mic check from Christophe Grand with what he’s been up to.
The Lisp Game Jam is on from 20-30 April 2018
Apropos is a weekly live discussion of Clojure/ClojureScript news with some panelists and then some live coding. Cool idea and format, episode one is out now, give it a watch.
Redux in 30 lines of ClojureScript
Oliver Hine goes through the looking graph, exploring GraphQL.

Libraries & Books.

Matrix is a data flow/spreadsheet like/reactive programming library for ClojureScript, and a port of the Common Lisp library Cells.

Tools.

Bruce Hauman released rebel-readline, a terminal readline library for Clojure/ClojureScript, and has integrated it into the most recent release of Figwheel. This work was sponsored by Clojurists Together.
A collection of Awesome Clojure REPL resources
While not strictly a Clojure tool, CircleCI has announced end of life for v1.0 at the end of August. I was able to move some Clojure projects to 2.0 a few months ago and it wasn’t too tricky, especially with their Clojure migration guide.

Recent Developments.

Feedback requested on the new ClojureScript 1.10 quick start

Misc.

The Bayesian Trap

64: 10x programmers, structural diffs, and whimsy

Mon, 26 Feb 2018 21:52:17 +1300

-main

Autochrome’s structural diffs for Clojure source code are very cool. I’ve long wished for something like this.
Metosin have recently published Retit, a new router for Clojure and ClojureScript. They’ve written about their motivations for creating it, and integrating it with Ring
Using Clojure macros to clean up error handling
Replacing the Clojurians Slack log
How we built Whimsical (with Clojure, ClojureScript, Aleph, reagent, and re-frame)

Libraries & Books.

Programming Clojure has a 3rd edition out with new sections on transducers and spec.
Configuron is similar to environ, but reloads changes when your project.clj changes, and has ClojureScript support.
thorn is a library for detecting homographs (strings that look similar/the same but have different characters). ‘Let’s talk about usernames’ is a good primer on why you’d want to use thorn.
clj-http-ssrf helps you prevent server side request forgeries when making requests with clj-http

People are worried about Types. ?

s/valid? does not tell me if the data is valid as supplied, the dangers of using conformers for coercion, and Alex Miller’s strong warning against it.

Tools.

I’ve been working for quite a while on re-frame-10x (née re-frame-trace) a debugging and inspection tool for re-frame-apps. We announced a major new revamp of it this week, if you use re-frame, I’d highly recommend checking it out.
TNS-48: Ability to track files that are not namespaces
Access control in Datomic Cloud
Reid McKenzie’s Docs Sketches
Overview of the nREPL

Recent Developments.

Why doesn’t Clojure support raw strings?

Learning.

A visual overview of the similarities and differences between ClojureScript and JavaScript
Clojurians, please share your knowledge with blogs

63: AI fire alarms, Parinfer, Clojure book deals

Mon, 19 Feb 2018 21:35:19 +1300

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Renzo Borgatti has a list of Rich Hickey’s answers to a bunch of commonly asked questions.
Reasoning about systems

Libraries & Books.

Humble Bundle has a deal on a bunch of O’Reilly FP books, including Living Clojure, Clojure Cookbook, and Clojure Programming.

People are worried about Types. ?

Spec making errors worse in Clojure 1.9

Foundations.

Project Detroit seeks to bring the V8 JavaScript engine to OpenJDK
The Java SE roadmap has been updated with support for Java 8 until January 2019.

Tools.

Cursive now supports Parinfer v3
Pyro is a new library that looks like it will vastly improve the experience of Clojure stacktraces, by showing the actual code that failed in the stacktrace.
The suite of core Clojure tooling continues to expand with test-runner.

Recent Developments.

Good note from Alex Miller on what’s involved in handling patches.
Allowing custom read-cond features

Learning.

Robert Stuttaford’s Clojure learning journey building a registration system for ClojureBridge

Misc.

“In 1901, two years before helping build the first heavier-than-air flyer, Wilbur Wright told his brother that powered flight was fifty years away. In 1939, three years before he personally oversaw the first critical chain reaction in a pile of uranium bricks, Enrico Fermi voiced 90% confidence that it was impossible to use uranium to sustain a fission chain reaction.” - There’s No Fire Alarm for Artificial General Intelligence

62: prepl, Clojurists Together, and readline

Mon, 12 Feb 2018 10:22:21 +1300

Notes.

Sorry for the less-than-weekly cadence of The REPL lately. Things have been pretty busy at work and home, plus it’s summer in NZ so I’ve been spending as much time at the beach as possible. Things are starting to settle down though, and The REPL should be returning to a more regular rhythm.

Thanks for reading!

-main

The thing I’m personally most excited about this week is the recent announcement from Clojurists Together that we have funded clj-http and Figwheel in our first funding round. We’ve been chipping away at this since January 2016, and it feels really good to finally start funding projects. If you’ve signed up as a member, I really truly appreciate it.
Bruce Hauman has a very cool demo and prerelease of a new readline library he is working on for Clojure/ClojureScript.
Nikita Propov on macros and API design, using the specific case of HTML generation. It added something to the way I think about API design when I read it.
Ramsey Nassar is definitely not working on a post-Clojure lisp.

Libraries & Books.

Java Concurrency in Practice is on sale in paperback and Kindle form

People are worried about Types. ?

When types are eating away your sanity. With a title like that, how could I not link it?
Parsing with clojure.spec
Twitter poll and discussion on where to locate your specs

Foundations.

What’s coming in Java 10
A talk describing the low-latency Z Garbage Collector from some of the team.

Tools.

C ode reloading woes (of which I’ve had many)
shadow-cljs has a snazzy looking docs site

Recent Developments.

The most intriguing news this week was this commit from Rich Hickey introducing prepl. Alex Miller gives some more context on Reddit.

Learning.

Purelyfunctional.tv has a new course on understanding re-frame
Prerendering a re-frame app with headless Chrome
Interactive GPU programming with OpenCL
The Power of Clojure: Debugging
Machine learning with Clojure in 2018

Misc.

Bryan Cantrill - The Hurricane’s Butterfly: Debugging Pathologically Performing Systems

61: Datomic Cloud, specs, and Atoms

Wed, 31 Jan 2018 12:43:23 +1300

Notes.

Thanks to everyone who sent me info about GraphQL after the last newsletter, it was very helpful!

-main

The annual Clojure survey is now on. It’s worth your time to fill it out. I’m looking forward to seeing the results this year, and what people are looking for improvements on.
Datomic Cloud is now out, and also has a post on HA. The new pricing model opens Datomic up to a much wider audience. Previously if you wanted to build a small project using Datomic you had to choose between paying for a $5,000 annual license after one year, getting no updates to Datomic after a year, or using Datomic Free which has other limitations. Now your Datomic license scales with your usage, and has a much lower entry point.
I really enjoyed Zach Tellman’s interview on Defn, well worth your time
Clojure Goes Fast - Introsepction tools: Java decompilers

Libraries & Books.

Russ Olsen has a new book coming out called Getting Clojure. It’s in beta now.
Parallel is a new library for parallel functions
wrench is another configuration library

People are worried about Types. ?

Foundations.

Quick tips for fast code on the JVM

Tools.

Jacek Schae on setting up Atom for Clojure development
lein-jlink builds on JDK 9’s jlink tool, and lets you build a custom (small) JRE for your Clojure app
shadow-cljs has a new user guide
Easily reloading your Clojure project in Spacemacs
A discussion on Bazel as a Clojure build tool. I’d been hoping for

Recent Developments.

clojure tools 1.9.0.315 and tools.deps.alpha 0.5.342 are out
Git Deps for Clojure. I’m not convinced that this is going to work very well in practice for public libraries, but I’ll acknowledge that I’m a bit biased. It’s definitely interesting, and worth watching.
There’s been some recent discussion about Clojure startup time
A post on the Clojure-Dev mailing list about the locking macro being 2x slowerthan a synchronised Java block

Learning.

Cool things in Clojure 1.9 from Nola Stowe

Misc.

Popularity - “Technical analysis is hard work. Following the crowd is easy, but it’s often a shortcut to the wrong place.”

60: Nitty-gritty details, slow starts, fast profiling

Fri, 12 Jan 2018 19:30:00 +1300

Notes.

Welcome back to the first issue of The REPL in 2018. If you took time off, I hope you had a great break away.

I’ve got a favour to ask this week. At Day8 we’re evaluating different backend technologies and are taking a hard look at GraphQL. We’re coming from a CQRS mindset, and GraphQL looks like it might be a good fit. I’d be really interested to hear about your experience if you’ve used it. There’s lots of information about what’s good about it, but less so about the problems people have with it. If you used it, what issues did you run into? If you looked at it, but decided not to use it, why?

Thanks!

-main

An AMA with Carin Meier is on shortly on ClojureVerse
Clojure’s slow start - what’s inside? - Clojure Goes Fast is one of my favourite new blogs of 2017, I’m looking forward to seeing what 2018 brings.
A new Hiccup compiler for ClojureScript
People share the nitty-gritty details of their Clojure workflow
I wrote a guide to public Maven repositories you may come across

Libraries & Books.

A comparison of front-end frameworks with benchmarks. re-frame came out pretty well here.

People are worried about Types. ?

Tools.

Cider 0.16 (Riga) is out
A new flame graph profiling tool for Clojure: clj-async-profiler
Profiling with jmh-clojure
Fellow Kiwi Liam Falconer also wrote about flamegraphs and benchmarks
Derive your leiningen project version from your Git history
Discussion about c reating a central documentation repository / website
autodoc helps automate publishing generated documentation
YourKit has their annual personal license sale on for the next few days. Normally licenses start at $499, but for a week or so each year they offer a personal license for $99. This is a pretty good deal if you ever need to dig into the guts of your programs.
Setting up Clojure on macOS in less than 2 minutes

Recent Developments.

Git dependencies for Clojure via tools.deps. See also the discussion on Reddit.

Learning.

Paper call for speaking at Dutch Clojure Day 2018

Misc.

Bryan Cantrill on Principles of Technology Leadership

59: Local mutable variables, weak memories, faster reduce

Mon, 11 Dec 2017 21:00:32 +1300

-main

Clojure 1.9.0 has been released! The Cognitect blog has the announcement, and there are some great release notes on GitHub.
Alex Miller has an intriguing comment on HN: “There is more to the generative testing story that has not yet surfaced. We’ve got another whole project related to this that is still a work in progress. Even without that, I think there is a lot of value to be had in spec right now.”
Zach Oakes on how Clojure’s documentation can leapfrog other languages + Reddit discussion
I wrote a post on how to update your Clojure projects to Java 9
A great article on making a faster Clojure reduce (for specific cases)

Libraries & Books.

clj-embed is a Clojure library for segmenting multiple Clojure runtimes in a single JVM
one-time is a One Time Password generation library. It looks ok, but you should always audit these kinds of libraries, ideally with someone experienced with cryptography.
Fulcro (nee Untangled) has hit 2.0 and has made a fork from om.next.
fulcro-inspect helps you debug Fulcro applications

People are worried about Types. ?

Strong Typing is for people with Weak Memories

Tools.

Bozhidar Batsov talked at ClojureX about the new release of CIDER and nREPL.
Colin Fleming, author of Cursive has an AMA on Clojureverse right now (as I send this).
Immutable names of things?

Recent Developments.

CLJS-2377 - Moves away from modules deprecated in Java 9. This is fixed on master, but not in a release yet.

Learning.

3 Clojure conferences to attend this winter
Conduit is a real-world re-frame app. It’s worth checking out if you’re looking for idioms of writing larger re-frame applications.
ClojureX videos are up

Misc.

TIL Clojure has local mutable variables (and they’re not dynamic vars or atoms)

58: Flares, ideology, and a birthday

Tue, 05 Dec 2017 02:45:09 +1300

Notes

I want to open this email by thanking everyone who has signed up for Clojurists Together. We’ve had a large number of individual developers get on board, as well as several companies. I wanted to especially highlight new company sponsors Centriq (Transduce Member) and JUXT (Filter Member). We really appreciate their support, along with everyone else who has joined up. Any individuals or companies that sign up before 13 December will be recognised as a founding member, so if you’re thinking about joining, now is the time.

-main

Gary Bernhardt gave a great talk at Strange Loop 2015 - Ideology. It talks about the beliefs underlying our claims, the unknown knowns. It’s my number one pick for this week.
ClojureVerse is relaunching

Libraries & Books.

Visualise the results of a Datomic transaction with datoms-say-what
Cambium is a new structured logging library
Raamwerk is a web framework built into the system library
Flare is a Clojure dynamic neural net library that looks pretty fast

People are worried about Types. ?

Reasons for spec not validating :ret and :fn. I find using Orchestra to validate :ret and :fn helps catch bugs early, especially when I’m iteratively developing

Tools.

Dynadoc: not your father’s documentation generator
Cursive 1.6.2 has some great new features for navigating to specs and re-frame handlers
How to setup HSQLDB with Datomic
I’m a bit late to the party on this one, but Smartparens was 5 years old in November

Recent Developments.

Clojure 1.9.0-RC2 is out
CLJ-1458: Enhance the performance of map merges. This ticket needs someone to help with setting up a benchmark harness to validate the potential performance gains.

Learning.

Database Structure in Re-frame, I agree with most of these, but would like to write up where I differ sometime.

Misc.

Dan Luu has an article on the quality of management decisions and sports

57: Caves, parsing, and fractals

Tue, 28 Nov 2017 01:13:12 +1300

-main

This week I was on the Defn podcast talking about Clojurists Together, this newsletter, and Deps. I had a lot of fun recording it.
Clojure Design Patterns shows how to take classic design patterns and implement them, mostly with functions.
A good gotcha to watch out for with parsing in clj-time. The same issue exists in cljs-time too.

Libraries & Books.

I haven’t fully grasped factfold yet, but it looks like a very powerful state machine/interpreter/modeling layer/state container

People are worried about Types. ?

Carp is a new typed, compiled lisp for systems level programming (and up)

Foundations.

An Introduction to JVM Performance

Tools.

re-jump.el, navigation for re-frame

Learning.

Roman Liutikov is working on Functional Cave. It will have ClojureScript tutorials coming from a JavaScript/React perspective.

Misc.

Software Estimation in the Fractal Dimension was pinging around the company Slack this week, and I thought it had some good insights

56: Clojurists Together, MAGIC, and a dose of Clojure

Thu, 23 Nov 2017 07:50:15 +1300

Notes.

The big news for last week, at least from my perspective, was launching Clojurists Together. This is a project designed to support open source Clojure software and keep it sustainable by paying maintainers. We’ve already had quite a few individuals sign up, but not too many companies yet. If you work at a company that uses Clojure, please consider signing your company up for a Company Membership.

-main

Ramsey Nasser on the MAGIC compiler for Clojure and the CLR
Clojure, EPL 2.0, and GPL compatibility

Libraries & Books.

Compound is a micro structure for re-frame data

People are worried about Types. ?

Following up from last weeks worrying on s/keys validations, Greg Mitchell gives his experience of using Protocol Buffers at Google
Worried about types + Clojure Elitism

Foundations.

Statistically rigorous Java performance evaluation
Fear and Loathing in Lock-Free Programming
Immer: persistent data structures for C++
2018 - 120fps and no jank

Tools.

boot-tools-deps allows you to read deps.edn files
Migrating from Boot and back to Leiningen
Vim Clojure Tooling Redux

Recent Developments.

ASYNC-119: Combines CLJS core.async macros namespace into main core.async namespace. ASYNC-142: Rename CLJS core.async namespaces to match Clojure ones. The combination of these two being resolved should make it a lot easier to write cross platform core.async code.

Learning.

Clojure Dose, a daily dose of Clojure snippets from Clojurians Slack
Get 40% off Mastering Clojure Macros from Pragmatic Press this weekend

Misc.

Tom and Lin-Manuel: An Appreciation/Jealous Rant

55: More type worrying, cats and dogs, and cache lines

Tue, 14 Nov 2017 08:26:17 +1300

-main

A Clojure performance nemesis: reflection. This is a really good overview of reflection in Clojure, how to spot it, and how to fix it.
I’ve launched a free and open source service Deps Versions for adding a dependency status badge to your open source Clojure projects. I wrote a bit more about it on the Deps blog.
State in re-frame
Cats and Dogs with Cortex Redux
A ClojureScript visual cheatsheet
David Nolen was on the CaSE podcast.

People are worried about Types. ?

There is a lengthy thread on the Clojure mailing list about spec’s unintuitive (IMO) behaviour for validating keys. The specific part that I’m worried about is that no error is thrown at runtime if you specify a keyword in s/keys that hasn’t been defined. It seems like the kind of thing that could leak into production, or mask bugs further down the line.
Semantic integrity checks is a new feature of a configuration language Dhall, which lets you verify that the semantics of your API haven’t changed. I could imagine something similar being applied to APIs that have been specced in Clojure, to automatically detect breaking changes.

Foundations.

Cliff Click talking about modern hardware performance and cache lines
Mark Reinhold and Brian Goetz on Moving Java forward faster, and Java’s new rapid six monthly release cycle. Highly recommended if you want to see the future direction Java is heading.
Here’s the release schedule for JDK 10
Intel has released persistent collections for Java. However these are for efficient usage of non-volatile persistent memory, not persistent data structures.

Tools.

Datomic now has a forum
Clojureverse has a poll on how you compile your ClojureScript
Thomas Heller on the background of shadow-cljs

Recent Developments.

Clojure 1.9.0 RC1 is out

Learning.

Mike Fikes on avoiding unnecessary conversions of JS objects to CLJS, and the resulting performance boost you can gain.
Clojure debugging

Misc.

Long time member of the Clojure[Script] community Chas Emerick has a Patreon up. If you’ve benefited from his work, either now or in the past, then consider sponsoring it.

54: Christmas cards, type worrying, and sentimental versioning.

Mon, 06 Nov 2017 08:23:19 +1300

Notes.

Hi folks, I have two exciting announcements this week.

First, I’m sending Christmas cards to readers of The REPL. This is a custom design by my wife, so you can only get it from me, this one time. If you’d like one, fill out your details. I’m only sending 80 cards, so get in quick if you’d like one.

Second, I’ve been working on Deps, a private Maven repository service (for storing your companies private JARs) this year. I have recently got a private beta up and running and already have several companies using it. If you’d like to stop running Nexus on that dusty server in the corner of the office, sign up and I’ll get you on board as soon as possible.

Thanks, and enjoy this weeks newsletter.

People are worried about Types. ?

There’s been lots of type worrying again this week.

Alex Miller has a good take on Clojure and types
Duelling Rhetoric of Clojure and Haskell
On Types and Intent

Foundations.

I don’t know how much use this would be for Clojurists, but Brian Goetz has a proposal for Data Classes for Java. Like last weeks Java proposals, its worth reading just for a succinct definition of the problem space.
I missed this when it came out, but Mark Reinhold has proposed moving Java to having two feature releases/year. There will also be an LTS version supported for at least three years which is roughly equivalent to what we have now.
In conjunction with the new release cycle is a proposal for a new versioning system.

Tools.

Lightmod is an all-in-one tool targeted at beginners for full stack Clojure. From Zach Oakes (of course).
Last week I got the link to Closh, the Clojure shell wrong, so it’s back again this week.
Enlighten mode in Cider looks cool

Recent Developments.

All quiet on the Clojure front, I’m expecting a 1.9 release very soon.

Misc.

Sentimental Versioning

53: Type wars, garbage collectors, and a Clojure shell

Wed, 01 Nov 2017 19:45:21 +1300

-main

Clojure 1.9.0-beta4 is out. It looks like the full release of Clojure 1.9 is very near.
Pyroclast has a snazzy new website out
IN/Clojure 2018 has opened their CFP

Libraries & Books.

Specialist Server is a GraphQL server driven from specs

People are worried about Types. ?

Foundations.

Project Loom is a proposal for Java to gain fibers (lightweight threads). Worth a read for the background on Java concurrency.
The Z Garbage Collector is another new project for Java, optimising for low latency (< 10ms) pauses and large heaps.

Tools.

Datawalk is a new tool for interactively exploring data structures at the REPL
Closh is a bash-like shell based on ClojureScript
Leiningen 2.8.1 is out with a bugfix release
tools.deps.alpha 0.2.167 is out

Learning.

Transducers from the ground up

Misc.

Alan Kay on Lisp being the greatest single programming language designed

52: Effective programs, Java 9, and Clojure 1.9

Sun, 22 Oct 2017 15:49:22 +1300

Notes.

Welcome back to The REPL. I’ve been taking a break after our new son was born, but I’m ready to get back to it. There was so much good stuff in Clojure over the last few months, and unfortunately I won’t have time to highlight it all. Thanks for reading, and enjoy!

-main

Clojure/Conj 2017 has just happened, and the stand-out talk for me was (of course) Rich’s talk Effective Programs - 10 Years of Clojure. I found it helped me understand the philosophy of Clojure even better.
Eric Normand is running a new conference Clojure SYNC in New Orleans in February 2018. There’s some good speakers lined up, and it looks like a neat event.
Help ship Clojure 1.9!
Matthew Gilliard has had a great series of articles on improving Clojure startup time with some new Java 9 features.

Libraries & Books.

clojerl: Clojure for the Erlang VM

People are worried about Types. ?

But expound makes the error messages better for developers. I’ve used this fairly heavily and find it makes a big improvement to understanding spec errors.
Phrase is another tool for error messages, but focusing on presenting the errors to the user. I haven’t used it, but it looks neat too.

Foundations.

Java 9 has been released, with tons of good stuff, including Compact Strings and new security features.
Watch out for the JDK 9 pitfalls for the unwary though, including the first APIs to be eliminated in the history of Java(!).
Opening up Java EE

Tools.

Leiningen 2.8.0 was recently released, and also recently turned 8.
Colin Fleming was on Talking Kotlin, talking about how he uses Kotlin with Cursive
jmh-clojure looks like a great way to use the very accurate JMH benchmarking tool

Recent Developments.

CLJ-2194: Spec metadata support
CLJ-1074: Added new literals for Infinity and NaN

Learning.

Alex Miller was on the CaSE podcast talking about Clojure
Clojurecademy is a new site for learning Clojure

Misc.

New Zealand just formed our next government this week. An Australian journalist wasn’t sure how to pronounce our Prime Ministers last name, so he called her office and was put through to ask her directly.

51: Orchestras, explorers, and nothing?

Sun, 13 Aug 2017 10:30:25 +1300

Notes.

Hi folks. It’s been a busy few weeks for me. I’ve been building an office in my garage, and am doing the plastering/painting/flooring for it. I’ve got lots to learn there, but I’m really enjoying it. This will be the last edition of The REPL I’ll be sending for a month or so. My wife is having a baby sometime soon, and then I’ll be on paternity leave.

-main

ClojureScript has a bunch of sneak previews of new features coming: Enhanced Code Splitting and Loading, and Integrating Node Modules
The Onyx/Pyroclast team have a new project for processing event streams in development: Roaming, and they have a Clojure SDK for it.
Brad Cypert on why he switched from Python to Clojure
A massive guide to re-frame from Eric Normand
Speaking of re-frame, Rails Girls Summer of Code has sponsored two people to work on re-frame for the summer. Here’s their first progress report. I’m mentoring this project, and really looking forward to seeing what they come up with.
Clojure design decisions: Rich already answered that!

Libraries & Books.

Tony Kay is now working full-time on F ulcro, a web framework for Clojure. This is a fork of Untangled. If you’re using it professionally, there’s a Patreon, and other ways you can support it’s development.
time.clj is a cross platform time utilities library

People are worried about Types. ?

Spec Oracle
Orchestra now supports ClojureScript
Schpec has a defn macro for pattern matching on specs (I think that’s what it’s doing?)
CLJS-2194: Spec metadata support

Foundations.

As far as I can tell there were no injuries at the JVM Deathmatch

Tools.

Cursive 1.6.0 is out with some big improvements for test navigation
Debux is a debugging/tracing library for Clojure and ClojureScript
Christophe Grand has also a released a lower level tracing library poucet
Source Map Explorer looks great for analysing your CLJS build size
Martin Klepsch with good advice on pinning Maven Snapshots
Lumo has hit 1.6.0
Stuart Halloway on REPL driven development

Recent Developments.

Clojure Android activity
nothing? predicate in Clojure
CLJS-2148: adds warnings for doing aget on non-arrays. This has been warned about for a long time, so it’s not a big surprise. It’s going to turn up a lot of problems for people, so library maintainers should start running this now so they can start fixing the warnings.
A related ticket CLJS-2198 adds safe array operations

Learning.

Misc.

Muzzle turns on Do Not Disturb on your Mac when you’re screen-sharing, so that no (potentially embarrassing) notifications show up.

50: Efficient matrices, and lisp editing

Thu, 29 Jun 2017 08:47:27 +1300

Notes.

The REPL turns one this week. Thanks to everyone who has read it, shared it with friends and colleagues, and sent me links.

-main

Clojure concurrency and blocking with core.async
Clojure Numerics, Use Matrices Efficiently

Libraries & Books.

Larch is an Elm like ClojureScript SPA framework
Ring-SSE from Bobby Calderwood
Haslett is a websocket library for ClojureScript

People are worried about Types. ?

Reify Health are using spec to generate sample data to get user feedback

Tools.

Shaun Lebron with a history of lisp editing
Clojure + Kibit and Eastwood

Recent Developments.

ClojureScript 1.9.660 is out, with a new news section on ClojureScript.org describing the changes
Mike Fikes on ClojureScript const var inlining and method head recurs in defrecords

Learning.

Guide to Reagent from PurelyFunctional.tv
I’m not sure if there’s an online link for this, but I got an email recently saying that Clojure/conj and Clojure/west are merging next year for one larger conference.

49: Datomic, a mirage, and deathmatches

Wed, 21 Jun 2017 12:30:30 +1300

-main

Stuart Halloway was on the defn podcast (audio at SoundCloud) talking about Cognitect, Spec, more from Datomic in the cloud (I’m excited for this), and the Clojure community.
Stuart Halloway again on why contains? is great design (I’m still not convinced), plus thoughts on docs.
Why transducers are not (yet) fundamental?
What Datomic brings to businesses
A new guide on reading Clojure characters that are hard to Google
Tim Baldridge talking about his thoughts on developer happiness, and learning an instrument.

Libraries & Books.

Miraj is a new web framework for Clojure

People are worried about Types. ?

Foundations.

If you’re in New York, you should head along to the JVM Death Match, between the different JVM vendors.

Tools.

Scrolling with pleasure, a masterwork on smooth scrolling.
Which lein plugins do you find useful?
Parinfer: why v2 is different
Publishing to Clojars in 2017

Learning

Rapid Web App Prototyping with ClojureScript
LispCast on the pros and cons of web frameworks

Recent Developments.

ClojureScript is setting up TravisCI for running tests

48: Delays, reuse, and ducklings

Wed, 14 Jun 2017 09:27:35 +1300

-main

I missed this when it came out, but I really enjoyed James Reeves’ keynote on Transparency through data. It helped me put into words some thoughts I had lingering on hard to understand code.
Delay: Clojure’s forgotten concurrency primitive
REPL Debugging without stack traces by Stuart Halloway
Reuse comes in Pints
Clojure use at Signal (but not the messaging app Signal)
Comparing Java’s verbosity with Clojure

Libraries & Books.

clj-duckling is a library for parsing text into structured data, e.g. dates, currency, distances
data-frame lets you use re-frame with Datascript as data storage

People are worried about Types. ?

Do we need 3, or just 2 error types?

Foundations.

Why does the G1 GC shrink number of regions? is a good look at how garbage collection handles changing workload types.

Tools.

What’s the simplest way to publish to Clojars?

Recent Developments.

Alex Miller has a Welcome to Clojure post on the mailing list
Generative Testing for Self-Hosted ClojureScript
CLJS-1977: defrecord should use murmur hashing like Clojure

Learning.

More linear algebra from Dragan Djuric
Clojure Gotchas with Unicode surrogate pairs

Misc.

I meant to put this in last weeks letter, but forgot about it when I was writing. What can a technologist do about climate change? from Bret Victor.

47: Duct, macro confessions, and getting a Clojure job

Wed, 07 Jun 2017 21:04:34 +1300

-main

Building Web Services with Duct
Derek Troy-West gave a talk “Scaling the Event Stream” about a Clojure/Cassandra distributed system that he built with an NZ company SMX. I worked with them on part of this system a few years ago, and it was a great team and project (talk starts at 6:30).
Confessions of a threading macro addict
The ultimate guide on Clojure concurrency from PurelyFunctional.tv
Authentication with Yada

Libraries & Books.

I’m still chewing over precept, a declarative programming framework, but it looks really interesting
Yesql is looking for a maintainer
Certificaat is a Let’s Encrypt client
fqcss is an interesting approach to CSS and ClojureScript
Programming Clojure, Third Edition is in beta with new material on clojure.spec
klang is a ClojureScript logging library
Introducing the Keechma Toolbox library
Chestnut 0.15.0 is out

People are worried about Types. ?

The broken promise of static typing
Data Validation with spec
Jeaye Wilkerson implores developers to use spec. I’ve been developing using Orchestra like he recommends, and have found it hugely helpful in checking return values

Foundations.

Proposed schedule change for JDK 9

Tools.

inlein 0.2.0 (Leiningen for scripts) is out
lein-protoc is a lein plugin for compiling protocol buffers

Recent Developments.

ClojureScript 1.9.562 is out, with Clojure 1.9.0-alpha17 parity
Mike Files on ClojureScript compiler performance

Learning.

Demystifying a Datomic error (I love the Discworld theme in this)
Video interview on how to get a Clojure job
K Nearest Neighbours in Clojure
Dragan Djuric with a linear algebra refresher on Vector Spaces, and Eigenvalues and Eigenvectors

46: Readable Clojure, debugging, and UI state machines

Sat, 27 May 2017 22:00:37 +1300

-main

Clojure/Conj 2017 info is out and it has an open CFP
Nikita Tonsky has some recommendations on Readable Clojure. I agree with most of them, it’s well worth a read and discussion with your team.
Filling gaps in TensorFlow’s Java API
Jeb Beach on State Machines in the UI

Libraries & Books.

re-mote is a REPL driven environment for remote operations on other machines

People are worried about Clojure. ?
The last few weeks have had a lot of discussion about Clojure, its problems, and its future.

Tools.

circleci.test is a new test runner that replaces the lein test runner. It has some very cool features like checking for IO in your tests and failing if you haven’t marked the test as doing IO.

Recent Developments.

tools.reader is nearing 1.0.0
0.0 and -0.0 now hash equally
CLJ-2141 has been fixed, qualified-* predicates now return true/false.

Learning.

Misc.

Kyle Kingsbury presents a Scala Days 2017 keynote: Anna Concurrenina

45: Integrity, Kotlin love, and Frankenstein

Tue, 23 May 2017 10:37:39 +1300

-main

James Reeves continues Advancing Duct
Robert Herrmann has created a directory of Clojure consultants. He’s also available for hire himself.
The videos from clojureD 2017 are up.
David Nolan - Idée Fixe at GOTO Chicago 2017.
A big discussion on Reddit about Clojure’s future growth

Libraries & Books.

re-frankenstein is a deviant fork (their words!) of re-frame. It allows you to run re-frame without global state. I’ve been thinking about this a lot, so it’s helpful to see some other ideas.
Towards Cortex 1.0 (a machine learning toolkit in Clojure)
You can now use Specter paths with EDN via specter-edn
CUDA matrices in Clojure with Neanderthal

People are worried about Types. ?

But they’re staying quiet this week.

Foundations.

JVM Anatomy Park: String.intern()
Why does Go not implement a compacting, generational GC?
Java SE 8u131 brings support for cgroup CPU and memory limits, allowing their use with Docker containers.
Steve Yegge on his newfound love of Kotlin.

Tools.

Daily Clojure workflow with CIDER
Lambda Island on Emacs and Clojure tooling
The always entertaining Bozhidar Batsov with another sip of CIDER at :clojureD 2017

Recent Developments.

Alex Miller has requested comments for var printing, relating to serialisation support for vars in EDN.
Thomas Heller has a new take on ClojureScript and npm
CLJ-2075: unroll comparisons to include three arity versions

Learning.

Cognitect have a bunch of useful articles about Datomic usage on their support site.
ClojuTRE 2017 is open for ticket sales and an RFP

Misc.

I transcribed Bryan Cantrill talking about integrity at GOTO. I’d strongly encourage you to read it and listen to the whole discussion.

44: Molecular gastronomy, an Arachne update, and ziggurats of transducers

Tue, 16 May 2017 18:00:40 +1300

-main

Arne Brasseur on Lambda Island turning one, and the rocky journey so far.
“I could see the eduction, presumably still wrapping the reified IReduceInit, perched atop a ziggurat of lesser transducers. I looked, and at the very bottom lay a blasphemous side-effectful invocation of map. I did not belong in this place.”
Onyx now has a Java API. At work we were building a new system and looked very seriously at Onyx. We talked with Michael Drogalis and Lucas Bradstreet and found them to be very knowledgable and professional to work with. I’d highly recommend putting Onyx on your shortlist if you need to do analytics, CQRS, or anything that works with streaming data.

Libraries & Books.

Ataraxy is an experimental data-driven Ring routing library from James Reeves. Think Compojure, but with data instead of macros.
test2junit 1.3.0 is out
huffman-keybindings is a neat way to generate short keybindings to commonly used UI components. Note that it’s licensed under AGPL-3.0 which makes it difficult to use with Clojure.
Luke Vanderhart has an update on Arachne in a Reddit comment
Process jobs with Redis and Farmhand

People are worried about Types. ?

Foundations.

What’s new in Java 9? (Besides Modules)

Tools.

Cursive 1.5.0 is out with a bunch of improvements. I wrote a post about the improvements relating to dependencies.
The last post had a bullet On Lumo’s Growth and Sustainability but was missing the hyperlink.
Prepack looks like it could really improve ClojureScript startup time. Combining prepack and the Closure compiler seems fruitful too
ClojureScript REPLs now support evaluating multiple forms on a single line.
Lambda Island again, this time on writing Node.js scripts with ClojureScript
Using lein to produce multiple artifacts from a Clojure monorepo. There’s been a slow trend of companies moving towards monorepos in the last few years. We’ve looked at it for work too, but decided against it for now.
Java Stream Debugger for IntelliJ looks very very cool

Recent Developments.

CLJS-2020 defmulti “miss” performance is poor

Learning.

The status antipattern describes an alternative to having a single “status” field to describe an entity.
Data wrangling with transducers for a machine learning problem
Dealing with lazy data in a with-open

Misc.

I watched this video about Allen Hemberger making every recipe in the Alineacookbook and documenting it in their own beautiful book. I’m still thinking about it a few days later. The teamwork that Allen and his wife Sarah for the project was inspiring to watch. They’re now working with the Alinea Group on a Kickstarter to produce a molecular gastronomy cocktail book.

43: Putting the Jigsaw back together

Wed, 10 May 2017 10:23:42 +1300

-main

Alexander Yakushev going deep on transducers and ETL pipelines
Bill Piel has a Kickstarter project for Sayid Pro, a tool for tracing your production Clojure code execution with minimal runtime impact. I’ve backed it, I’d encourage you to take a look at it too.
ClojureScript Ejecta by Mike Fikes

People are worried about module systems. ?

The Component v Mount debates have nothing on the current controversy over Java 9’s inclusion of a module system (Jigsaw). If you’re unfamiliar with Jigsaw, Toby Crawley has a good overview of it in his talk on Clojure, Java 9, and You.

It started with IBM and Red Hat publicly announcing they would vote no on the current version of Jigsaw
They also authored an extensive document about their concerns with the spec
Mike Hearn had a good post about the IBM and Red Hat’s documents taking the opposing stance (that Jigsaw was good).
Mark Reinhold wrote an open letter to the JCP Executive Committee (who would be voting on Jigsaw) asking them to vote for it.
In the last day or so, the JCP Executive Committee voted 10:13 againstadopting Jigsaw.
There are now another 30 days where Jigsaw can be revised and resubmitted for another vote.

It’s not clear yet what is going to happen to the release date of Java 9 now that Jigsaw has been rejected, but it seems likely that it will be delayed further.

Libraries & Books.

Specql is a Postgres database library that makes use of spec and name
Ring 1.6.0 is out after a substantial gestation and feedback period. The major feature of this release is support for asynchronous handlers.

People are worried about types

But Metosin have a solution to help

Foundations.

Azul has a new JIT compiler for their JVM. Gil Tene (Azul CTO) has a post about the features of the compiler.

Tools.

On Lumo’s Growth and Sustainability

Learning.

Clojure Exchange 2017 has an open call for papers.

Misc.

Continuing my love of all things Joyent: Empathy is a core engineering value, on empathy and the idealised super-engineer. Highly highly recommended.

42: The REPL returns with a spec split.

Fri, 28 Apr 2017 19:28:44 +1300

Notes.

Long time between drinks for The REPL. There’s been family illness + work stuff that delayed me writing, but it’s back now.

-main

Performance improvements to CLJS hash-maps from Promptworks
Developing the language of the domain

Libraries & Books.

Matthew Jaoudi mixes up some baking-soda for combining Reagent and Reactstrap
spec-provider infers a spec based on sample data
restpect does integration tests for HTTP APIs
datofu provides common utilities for Datomic

People are worried about Types. ?

Criss seems a bit worried about Haskell’s runtime type errors
Martin Trojer thinks “All roads lead to Haskell”

Foundations.

Truffle Ruby on the substrate VM
How many Cloud data centre regions are needed world-wide? James Hamilton (Distinguished Engineer at AWS) thinks 10^3.
The true impact of modular Java

Tools.

Introducing Gradle build cache

Recent Developments.

The big Clojure news this week was Clojure 1.9 split spec out into its own library to help Clojure 1.9 move towards production while keeping spec in alpha.
Much (all?) of Clojure’s infrastructure is now served over HTTPS
Var serialisation serialises identity, not value

Learning.

Techniques for Efficiently Learning Programming Languages
Making software testing easier with Clojure
On the judicious use of core.async

41: A joker, a neanderthal, and a javanisse walk into a bar

Tue, 11 Apr 2017 08:36:46 +1300

Notes.

Just a short newsletter this week as I’m short on time, preparing for an upcoming talk, and starting a new project at work.

-main

I haven’t had a chance to watch too many of the conference talks yet, but I really enjoyed Toby Crawley’s Clojure, Java 9, and You, Paul De Grandis’ Faster Delivery with Pedestal and Vase, and Tim Baldridge’s Core.Async in Use.
Which Clojure testing library is most used?

Libraries & Books.

Neanderthal 0.9.0 has a release post out

Foundations.

Java 9 Countdown
Java Epsilon GC - a new GC that doesn’t do any garbage collection(!).

Tools.

Unravel is a new Socket REPL with some nice features.
Joker is a Clojure linter and interpreter written in Go

Recent Developments.

After my post last week about predicates returning nil, Alex Miller suggested opening an issue.
I opened CLJ-2141 which has become the most voted issue on the Clojure tracker in short time. Alex Miller has done a bunch of good work benchmarking the different options, and come up with an approach.

Learning.

Misc.

Make sure to keep the javanisse happy in your next interview.

40: predicates returning nil, functions returning functions, pirates of the JVM

Fri, 31 Mar 2017 19:51:48 +1300

Notes.

Clojure/west is on as I type, and the videos have already started coming out. I haven’t had a chance to watch many yet, but I enjoyed Michael Drogalis’ talk on Pyroclast. I wish I could be there, perhaps next year there can be a Clojure/south in Australia or NZ?

-main

I’d seen Skyliner when they launched, but didn’t realise they were using Clojure. Here’s a good 14 month experience report.
Mark Engelberg was interviewed as a pirate of the JVM
Comparing Reagent to React.js and Vue.js

Libraries & Books.

The incredibly prolific Daniel Higginbotham is working on another book about parallel programming. You can buy the book in beta now.

People are worried about Types. ?

Carin Meier’s “Living the lean startup with Clojure.spec” was great, and gave me some ideas for a new system we’re working on at Day8.
Protocol support with spec?

Tools.

There is a preview out for Keechma’s new devtools

Recent Developments.

Last week there was a thread on the clojure-dev mailing list about new predicates returning true, nil, or false, rather than the traditional true/false.
I wrote an article outlining the pros and cons of that decision today.

Learning.

Onyx released a sample application showing the Commander pattern in action with Kafka, Onyx, and Datomic.

Misc.

Ben Evans on self-driving cars and their second order consequences

39: Graphql, Darkleaf, conflict resolution

Mon, 27 Mar 2017 19:32:51 +1300

Notes.

Welcome to another week of The REPL. Please feel free to send me any links for interesting Clojure stuff, as I don’t always catch everything.

-main

Datomic has a new set of training videos
Of Routes and Resources (and Yada)
Configuring Clojure Apps

Libraries & Books.

Walmart Labs has open sourced Lacinia, a GraphQL library. They also have a good writeup on their motivations for creating it.
Codependence is an extension to Integrant
Fixpoint provides clojure.test fixtures and datasources
Neanderthal 0.9.0 looks like it is going to be blazingly fast, the release is just around the corner.
Darkleaf is a bidirectional ring router. Great name.

Foundations.

Research Debt
A Constructive Look at TempleOS - TempleOS has some really interesting features if you look at it closely.

Tools.

IntelliJ 2017.1 is out

Recent Developments.

CLJ-2133: Clarify documentation for the satisfies? function

Learning.

Resolving Clojure dependency conflicts
Datomic Tutorial

Misc.

My favourite schadenfreude is still CA schadenfreude.

38: The truth about nothing, integrant, shadows

Mon, 20 Mar 2017 21:32:53 +1300

Notes.

This week I wrote an article speculating about the subtext of Alphabet’s lawsuit against Uber.

-main

James Reeve’s Integrant was definitely the standout link for me this week. It is an alternative to Component and Mount, and I really like it. I highly recommend it, just to hear his thoughts on libraries and frameworks.
The prolific Daniel Higginbotham has a new site Community Picks up which aggregates book recommendations for subreddits, and he has a new book/quest out: Deploying Your First Clojure App… From The Shadows.
Everybody OOMs

Libraries & Books.

Clojure Standard Library March 2017 update
Postagga, a natural language processing library
muance, a virtual dom library for ClojureScript

People are worried about Types. ?

Stuart Halloway provides Clojure spec’s missing piece

Foundations.

Coding for SSD’s
Decreasing 99%ile file system latency by 42x
OLTP through the looking glass, this paper explores speeding up a database 20x by removing components that were needed 20 years ago when RAM was much smaller than database sizes.

Tools.

Cursive 1.5.0-eap3 is out
Virgil recompiles your Java files inside your lein repl

Recent Developments.

Clojure 1.9.0-alpha15 is out

Learning.

The truth about nothing

Misc.

Good advice from aphyr on h ow to do well at your next technical interview

37: Lenses, hashing, and Metrics that Matter

Sun, 12 Mar 2017 09:40:57 +1300

Notes.

It’s been a pretty wet week here in New Zealand. I’ve been working on Deps and experimenting with Google’s new Cloud Spanner. I’m liking what I’m seeing so far, I’ll put together an article with my experience in a few weeks.

-main

Bill Piel is looking for feedback on Sayid PRO, a tool to debug and profile Clojure in production
A (somewhat heated but still valuable) discussion on Navigators, Lenses, and Specter.
Counting lines 60x faster than wc with core.async

Libraries & Books.

Is someone writing a Datomic book?

Foundations.

A scary study showing how distributed storage systems (Cassandra, Zookeeper, Kafka, e.t.c.) handle file system bugs (or don’t handle them).

Recent Developments.

CLJ-1860: 0.0 and -0.0 compare equally, but hash differently
CLJ-2123: Lighter-weight aliasing for keywords

Misc.

Metrics That Matter

36: Nihilists, quadratics, and great expectations

Mon, 06 Mar 2017 21:14:03 +1300

-main

Nathan Marz on Clojure’s missing piece - Specter
From Ruby to Clojure
What makes Clojure Clojure?

Libraries & Books.

lambdaisland/uri is a clj/cljs library for handling URIs, including RFC compatible joining of relative URIs (./foo, ../bar).

Foundations.

Rust’s language ergonomics initiative + HN comments. Something like this for Clojure would be amazing.
Accidentally Quadratic - Capistrano server definition
Java 9 Enters First Bug Fixing Round
JVM Options cheat sheet

Tools.

Gradle’s new compile avoidance and incremental compilation look really good. Perhaps some of the same techniques could be used for ClojureScript compilation? There are also features to help prevent library consumers depend on transitive dependencies.
Using lein-test-refresh with expectations
repl.it now supports Clojure
Clojure oriented Ergodox layout
lein-blacklist is a plugin to stop certain namespaces from being required.

Recent Developments.

CLJS-1954: ClojureScript 1.9.493 and up break usage of core.async, due to an updated Google Closure dependency
Release date for 1.9 (spoiler: there isn’t one yet)

Learning.

Functional and syntactic abstractions in Lisp
ClojureX 2017 sneak peek

Misc.

Nihilist Reviewboard

35: The Cantrillogy, Write Behind Logging, "With change comes risk"

Sun, 26 Feb 2017 21:13:24 +1300

-main

Clojars is now officially a member of the Software Freedom Conservancy
“In this day and age of raging debates about type systems, … it’s refreshing to hear Sam prioritise the lowering of cognitive load”
“We’re reassured when we see lots of recent change, lots of contributors, and lots of new stuff appearing. In reality I think that’s almost exactly the opposite of what should reassure us. With change comes risk.”
A Majestic Monolith in Clojure
Dragan Djuric has slides up for his talk on Clojure on the GPU

Libraries & Books.

Transforming Data with ClojureScript is a new interactive beginners book on ClojureScript and Functional Programming
core.async 0.3.441, and 0.3.426 are out with some fixes for handling exceptions in go blocks

People are worried about Types. ?

Soft failures with Spec

Foundations.

Non Volatile Memory (NVM) bridges the gap between the throughput and latency of flash, and the durability and capacity of flash. This changes a lot of the assumptions and constraints in storage systems and databases. This article on Write Behind Logging shows how taking advantage of NVM’s unique properties sped up throughput by 1.2x-1.3x, and failure recovery time by 100x. The paper was co-authored by Andy Pavlo who showed up here a few weeks ago with his talk about Peloton.
Eric Normand has written a bunch of articles this week about th e JVM and Clojure
The Future of Java in the Enterprise (including InfoQ’s thoughts on Clojure adoption)

Tools.

Howard Lewis Ship has released vizdeps, a lein plugin to visualise your dependency tree
JetBrains 2016 in Review

Recent Developments.

A mailing list thread on contributing Specter to Clojure core

Learning.

A deep dive into Clojure’s next and rest functions

Misc.

If you also enjoy mainlining Bryan Cantrill, BSDNow has released The Cantrillogy, three back to back Bryan Cantrill interviews.

34: Magic, wisdom of the ancients, and fire for everyone

Fri, 17 Feb 2017 17:08:25 +1300

Notes.

I’ve started a Facebook page for The REPL. If you’re into that kind of thing, you can check it out. I won’t be offended if you don’t though.

-main

The Clojure/West 2017 speakers list has been announced
Ramsey Nasser on Magic + Reddit comments. He’ll also be speaking about it at Clojure/West
Eric Normand runs a weekly FP/Clojure newsletter at PurelyFunctional.tv
re-frame subscriptions got even better
The future of Clojure vs Go (on Reddit)

Libraries & Books.

I’ve mentioned these in previous newsletters, but the author of “Clojure Standard Library” has been publishing related screencasts weekly on different Clojure functions: Clojure Pills.
sv.system: leverage conventions to structure your component-based Clojure systems
or you could try compost, a variation on Component (but still compatible with Component)
graphql-builder: a GraphQL client library for Clojure and ClojureScript. A good example of using cljc to make a highly portable library.
scrum: State Coordination for Rum

People are worried about Types. ?

Fogus on clojure.spec: Data Design 01 - Sketching a Struct
Bytecode and performance of optionals vs if-null in Java

Foundations.

Arrays of Wisdom of the Ancients
Java Flame Graphs: Fire for everyone

Tools.

sudo apt-get install planck
crepl can sync atoms across time and space
Electron + Figwheel, and CLJS + Electron Cleanup, both from David Owens II
use-package.el moving into emacs core
Pyroclast has a snazzy website and logo

Recent Developments.

ClojureScript had a bugfix release: 1.9.473
CLJ-2108: Loading core specs affects startup time
CLJ-1138: data-reader returning nil causes exception
CLJ-2066: Reflection on internal classes fails under Java 9
CLJ-2103: s/coll-of and s/every take a long time to generate if :into is not provided
There’s too many core.async tickets with recent movement to list, but it sounds like there will be a release soon, so take a look at the list if you have any pet bugs you’re tracking.

Learning.

Misc.

How to Fix a Bug, Blindfolded

33: Data dramatics, and an "intrinsically unsafe" database (guess which)

Fri, 10 Feb 2017 16:05:27 +1300

-main

The biggest ‘wow’ article for me this week was Pyroclast, an in browser simulation tool for an Onyx cluster. It looks like it could speed up iteration by a factor of 10-1000x.
The 2016 State of Clojure survey has been released
I wrote an analysis of the free text survey question
Building a Chrome extension with ClojureScript - Hacker News Lookup
Clojure memory leaks in production (spoiler, it was memoize)
There are some cool project ideas for the Clojure Google Summer of Code 2017 program (Clojure hasn’t been accepted yet).

Libraries & Books.

serverless-cljs
Mozilla has renamed datomish, their Datomic inspired store to mentat
toucan: A (classy) Clojure ORM from Metabase

People are worried about Types. ?

There was plenty of type worrying (but maybe less than last year?) in the Clojure Survey responses.

Foundations.

The always excellent Dan Luu on web bloat
A Jepsen test of MongoDB by Kyle Kingsbury. I award no points for guessing that Mongo’s first (and still in use) replication protocol turned out to be “intrinsically unsafe”
Java 9 will change the way you traverse stack traces. Maybe it will change the way we traverse Clojure ones too?

Tools.

calvin: A minimalistic CLJS build tool which doesn’t require a JVM (!)
Faster Meta-development with Boot by Alan Dipert with a demonstration of how to avoid needing to restart Clojure programs in development.
Vim turns 25 and releases Vim 8
Provisioning Datomic using Packer and Terraform

Recent Developments.

CLJ-1496: Add a new arity to ex-info that only accepts a message
CLJ-1776: Test that collections are valid statements

Learning.

Functions Explained Through Patterns

Misc.

Aesthetic Engine 2 provides an abstract visualisation of webpages. I learnt a new-to-me term “Data Dramatisation” too.

32: Planck, clear thinking, collaborative REPLs, neanderthals

Mon, 06 Feb 2017 21:05:29 +1300

Notes.

A big thanks to everyone who shared The REPL last week, I had the biggest bump in subscribers since it was launched. Welcome to the new subscribers!

-main

Programmatically accessing ClojureScripts Externs Inference
It’s time to get Clojure ready for Google Summer of Code
What’s next for Clojars in 2017?
Who is using Clojure in production, and would you do it again?
Why React & re-frame are fast in 7 performance hacks
Know your keywords

Libraries & Books.

kabel 0.2.0: a bidirectional wire to pass Clojure values between peers
vase: data driven microservices from Cognitect, and a blog post about it.
system 0.4.0 is out with some neat changes for abstracting middleware like social sign-on libraries
lambdaroyal-memory 0.8.3: STM-based in-memory database storing persistent data structures

People are worried about Types. ?

Foundations.

Read-Eval-Print-λove 004 is out
An extremely well reasoned design document for Go’s proposal to make time measurements monotonic. It’s well worth reading for the clear thinking and technical writing.

Tools.

Planck 2 is out with Linux support
Light Table 2017 Roadmap. I’m very happy to see continued development on it, it’s an especially great tool for beginners.
crepl: a collaborative (!) ClojureScript REPL

Recent Developments.

If you use core.async, it’s worth being aware of some bugs around throwing and catching exceptions

Learning.

EuroClojure 2017 is going to be in Berlin on July 20-21
Moving Datomic storage from PostgreSQL to DynamoDB
How to run Neanderthal with Atlas BLAS from Ubuntu Repositories

Misc.

Continuing my nerd crush on Joyent/Bryan Cantrill (whose name I embarassingly misspelled as Brian last week): Hitting the moon on the first shot. It’s about the rigorous engineering culture at Joyent. It sounds like a good way to build reliable software.

31: Snowmobiles, spiders, type B personalities

Sun, 29 Jan 2017 01:49:30 +1300

Notes.

I was talking with some Clojure developer friends and they mentioned they’d only recently discovered this newsletter. It was a reminder that not everyone knows about it. If you enjoy The REPL, would you consider sharing it with one of your friends/coworkers/bystanders? Thanks for reading!

-main

There’s Immutable and then there’s Immutable
The Ten Rules of [Datomic] Schema Growth
Clojure is for type B personalities
JavaScript modules in ClojureScript, and Externs Inference, which both tie into the release of ClojureScript 1.9.456
Arachne has an alpha release out
‘Live’ programming, server-side
ClojureScript: The industry’s favourite functional frontend language

Libraries & Books.

boot-new generates new projects based on boot/leiningen templates
Datomic Doc manages :db/doc strings in your Datomic database
Skippy McSkipface tracks resource dependencies

People are worried about Types. ?

Java Without If

Foundations.

Java SE State of the Union
Introducing Riptide: WebKit’s Retreating Wavefront Concurrent Garbage Collector

Tools.

Recent Developments.

Release notes for ClojureScript 1.9.456

Learning.

Reagent Deep Dive part 4
Disambiguating KBpedia Knowledge Graph Concepts
Grokking Clojure’s thread-first and thread-last macros

Misc.

“I feel that we’ve entered a new phase here where the extant infrastructure providers — hardware providers — are now going to enter a new and much steeper phase of demise. … If I were those companies, I would seriously start carjacking [AWS] Snowmobiles. I mean, turn them around, right? I’d do something.”

Brian Cantrill - The economics of private clouds

30: Clojure pills, knowing your tools, spandex

Fri, 20 Jan 2017 14:41:33 +1300

-main

Knowing your tools
Zach Tellman on the appropriate use of nil
Clojars is joining the Software Freedom Conservancy. If you have any issues or questions, you can raise them on the linked email thread.
Reagent deep dive part 2 and part 3
Clojure in Berlin

Libraries & Books.

aws-arn: parse AWS ARNs in Clojure
Max Penet dons some spandex to query Elasticsearch
net: the Clojure netty companion
dom-top from Aphyr (SFW)

People are worried about Types. ?

Uncle Bob sure is worried

Foundations.

Rich Hickey on hierarchies (2009)
The memory models that underly programming languages
Shenandoah GC in a Tweet
TruffleRuby Status (Truffle is a language implementation framework for the JVM)

Tools.

boot-figreload - first class figwheel support for Boot
IntelliJ IDEA 2017.1 EAP is out
Sayid - a tool for debugging and profiling Clojure
Clojure on Visual Studio Code
Lispy and clj-refactor worship

Learning.

Ryan Kneufeld has announced ClojureScript Days, a series of four half-day conferences focused on ClojureScript
Clojure Pills - a weekly screencast on the functions in the Clojure standard library
Running Clojure code on AWS Lambda
Reading Clojure
Principal Component Analysis in pure Clojure

Misc.

I really, really enjoyed this discussion on the design and implementation of OK Log, a log management service.

29: Playing chess without the board

Fri, 13 Jan 2017 14:40:36 +1300

Notes.

It’s a lovely sunny day here in Auckland. I hope you’re enjoying summer if you’re in the southern hemisphere, and keeping warm if you’re in the north.

-main

Evolving user interfaces with re-learn

Libraries & Books.

Mach is a remake of make in ClojureScript
Tire-iron brings the reloaded workflow to ClojureScript
Dirac has reached 1.0.0 and one year old. I use Dirac heavily for the inline REPL in Chrome devtools and debugging at breakpoints. I highly recommend looking at if if you do ClojureScript development.
Ring 1.5.1 released to fix a path traversal vulnerability
Pedestal 0.5.2 has some bug fixes and security updates for the path traversal vulnerability too
Immutant 2.1.6 was also released

People are worried about Types. ?

Fogus on clojure.spec and why s/or exists

Foundations.

Why does the JVM have a maximum inline depth?

Tools.

crop: internal tools worth opening

Learning.

Clojure/West cfp and ticket sales are now open
Reagent deep-dive, part 1

Misc.

“I want you to imagine you live in a world where everyone plays Chess against everyone else. … The oddest part of this however is that no-one in this world has actually seen a Chessboard. … Unbeknownst to either player, there is actually a board and when they press a piece then a piece of that type is randomly selected. … But all of this is hidden from the players, they don’t know any of this exists, they have no concept there is a board … all they see is the control panel and the sequence of presses.”

- Why big data and algorithms won’t improve business strategy

28: being stateful, reagent mysteries

Mon, 09 Jan 2017 17:28:38 +1300

main

Reagent Mysteries - Part 3: Manipulating the DOM
Making code fast: measure what you intend to measure - Jake McCrary is not the first or last person that will run into laziness issues when performance testing.

People are worried about Types. ?

Creating a spec for destructuring by Alex Miller
Kotlin null-safety in Clojure

Foundations.

Joe Duffy on being stateful

Tools.

Cider is taking donations on The Open Collective. If you use Cider, I encourage you to donate to keep it going strong.
Zach Oakes has released a hosted version of his IDE Nightcode: nightcoders.net
Clojars has a new policy for deployments
A recent thread on Cursive REPL completion suggestions

Learning.

JUXT are running one-day training courses in the UK
Packaging JS libraries for CLJS with CLJSJS
How to use a charting library in Reagent

Misc.

I was sad to hear that James Hague is finishing his blog “Programming in the 21st Century”. It was and still is one of my favourite blogs.

27: Code is Data, Reagent mysteries, omnivorous config

Sat, 31 Dec 2016 11:28:41 +1300

Notes.

If you took a break over the holidays, I hope it was a good one. I’ve been at the beach with my wife and one year old son, so it’s been a mix of relaxing and defending the baby from a bach that hasn’t been childproofed. Best wishes for 2017!

-main

A great article “Code is Data” from James Reeves responding to an earlier disillusionment with Clojure article.
An interview with James Reeves around his work on Ring, Compojure, and his many other open source projects.
Deep Learning in Clojure with Cortex from Carin Meier
Paulus Esterhazy on Reagent mysteries - part 1: vectors and sequences, and part 2: reloading?

Libraries & Books.

chromex from the indomitable Darwin: write Chrome extensions with ClojureScript
naga, a Datalog based rules engine
omniconf is an omnivorous (my description) configuration library that verifies your config on startup

People are worried about Types. ?

But not this week.

Foundations.

Accidentally Quadratic - Chrome SSE parsing
Modern garbage collection
Operation Costs in CPU Clock Cycles
Why Aeron Matters
JVM at Google
Java Champions respond to the FUD article from The Register about Java SE usage.

Tools.

How boot solved our FTP problem
Code indexing with lein-codeindex for vim and emacs
More on Datomish from Mozilla, their database inspired by Datomic and Datascript.
Saving your Emacs customisations somewhere else
YouDebug sounds like an incredibly useful debugger for remote sites where you don’t have access to customer infrastructure. I wonder if it can work with Clojure?
I’ve been working on deps.co - private hosted Maven repos. You can sign up for the launch list if that sounds useful for you and your team.

Learning.

There is a Clojure workshop in Stuttgart, Germany
Threading Pipelines in Clojure

Misc.

Standing in the Shadow of Giants - Zach Tellman on open source culture and migration.

26: Christmas REPLs, deps, and a hot macchiato

Sat, 24 Dec 2016 23:32:43 +1300

Notes.

I’ve just launched the site for an app I’m working on: deps. It’s a private, hosted Maven repository service. If you were wondering what to get me for Christmas, take a look at the site and if you’d like to never manage Maven or Archiva again, sign up for early access.

Thanks for reading The REPL this year and have a great Christmas!

-main

Yogthos on Macchiato and using Ring as it’s foundation, and Macchiato Modules.
Choosing Functional Programming for Our Game, seems quite ambitious to me, but the proof is in the pudding.
The State of Clojure in India

Libraries & Books.

Datomish: A persistent relational store inspired by Datomic and DataScript, from Mozilla
Christophe Grand takes us deeper into macroception with macrovich
Contextual debugging with Om Next and Untangled
Arachne community update 5

People are worried about Types. ?

specmonstah is a new library from Reify Health for setting up testing data. But you should add it to your dependencies just for the name alone.

Foundations.

lazySet and putOrdered and the JMM

Tools.

Autocollapse ns definitions in emacs

Learning.

Lambda Island on seq and seqable
Identicons with ClojureScript

Misc.

Consus puts Paxos in your Paxos so you can replicate while you replicate. (This and the linked paper are a really good read).

25: Shingles, splinters, and smash bros.

Fri, 16 Dec 2016 21:13:45 +1300

Notes.

There’s lots of good stuff every week, but the last few weeks, in particular, have been a bumper crop, and I’ve had to leave a lot out. A good problem to have.

-main

Clojars has a new (low volume) mailing list for people who run Clojars mirrors.
Reminder that the State of Clojure survey is still running until December 23rd
Zach Tellman is hanging out his shingle
My disillusionment with Clojure and lisps (but not mine)
Goodhertz - config to code

Libraries & Books.

re-frame 0.9.0 is released
karma-reporter has a new release for pretty printing CLJS tests
The mount vs. component wars have a splinter faction: mount-lite
Odin is an extensible logic DSL from Timothy Baldridge
Special, a condition system for Clojure
Joker is a small interpreted dialect of Clojure written in Go
edn-java 0.5.0 was released

People are worried about Types. ?

Self Healing Code with clojure.spec

Foundations.

Minimum realistic GC time for G1 collector on a 10GB heap, with stellar comments (as usual) from Gil Tene
Let’s stop copying C

Tools.

Even if you don’t use Nightlight, you need to read the release notes just for the humour value alone. 1.3.0 is out.
I’m still not sure what to think about running Maven plugins in Boot or Leiningen builds

Recent Developments.

CLJ-308: protocol-ize with-open
A discussion on error messages
A rationale for using the s/def pattern

Learning.

Spend a few minutes reading Christophe Grand’s code mixing macros and code in cljc to support clj, cljs and self-hosted cljs.
Tale of Timezones and how FP is the Easy Way
Tips and Tricks for Component
PurelyFunction.tv is giving away some Clojure books

Misc.

And now for something completely different that I really enjoyed this week: Things of Beauty: Super Smash Bros. as Spectator Sport. N.B. the video has some salty language.

24: Clojure Surveys, Pimp my REPL, Checkmate

Tue, 13 Dec 2016 09:40:47 +1300

Notes.

The newsletter is a bit late this week, life’s been full of weddings and Christmas preparations. I hope your holiday preparations are going well too.

-main

RIP Anthony Grimes. I didn’t know Anthony personally, but he had a big influence in the Clojure community. There is a fundraiser for his family at GoFundMe.
The annual Clojure Survey is out. It closes on December 23rd. If the future of Clojure is important to you (and if it’s not, why are you reading this newsletter?), you should take a few minutes to fill it out.
Timothy Pratley writes about the hallway track at Clojure Conj 2016, and gives a survey of what people are using Clojure for.
I’m really excited for ClojureScript Externs Inference. This builds on the work Maria Geller did last summer in her Google Summer of Code work
One Weird Trick to Become a Clojure Expert
Data Science up and down the Ladder of Abstraction which references one of my all time favourite articles: Up and Down the Ladder of Abstraction by Bret Victor.
The ClojureX videos are out
A good talk on C, Crypto and Clojure by lvh

Libraries & Books.

The Clojure Standard Library is a new book by Renzo Borgatti and published by Manning. It’s in early access now, and expected to come out in Spring 2018. It looks like a massive but valuable undertaking.
Continuing this year’s trend of failure/retry handling libraries, comes an entry from Max Penet: Checkmate.
datalog-rules: Utilities for managing Datalog rulesets from Clojure.
docker-fixture: Docker containers as clojure.test fixtures [Ed: 😱]
Martin Klepsch has a new release of Derivatives out. It creates trees of derived values (similar to re-frame), but without a global db state.

People are worried about Types. ?

Allen Rohner gave a talk on Spectrum, a static ’typing’ library for Clojure.Spec at ClojureConj
Parsing with clojure .spec for the Advent of Code
Brandon Bloom and Gary Fredericks had a good discussion on Spec and versioning on Clojurians Slack.

Foundations.

Tools.

A Challenger Approaches! Clojure-Kit is a new Clojure plugin for IntelliJ. It’s still quite new, but looks like it has a lot of features already (structural editing, lein/boot support, REPLs, dataflow).
Pimping Gorilla REPL with React and ClojureScript
Clojure Jobs Resources

Learning.

Game development with Clojure/ClojureScript
Writing a Halite Bot in Clojure
An alternative to mocking with var redefinition

Misc.

Juxt XT16 looks like it was a lot of fun.

23: spec-tacular, macchiato, and deep learning

Sat, 03 Dec 2016 09:08:48 +1300

Notes.

There were several big pieces of Clojure news this week. First, Datomic announceda change in license to allow unlimited processes and a new client API suited for microservices. I wrote a guide to the licensing changes. Second, Clojure Conj is on as I write this, and has been getting all the videos out in record time. I’ll put some of my favourites in the next letter. Finally, Clojars has joined the Software Freedom Conservancy, and announced the Clojars Community Committee to support diversity and open source development in the Clojure and ClojureScript communities.

-main

spec-ulation by Rich Hickey
Macchiato, ClojureScript for the server from Yogthos
Adventures in client-side routing with re-frame and OAuth
Bringing bookmarklets back with ClojureScript and boot
Writing Clojure and ClojureScript macros in a cljc file. I’ve run into this issue myself too.
ClojureScript almost as fast as optimised C by Mike Fikes

Libraries & Books.

durable-ref: Durable reference types for Clojure, with some excellent docs.
alia, a Cassandra client has released 4.0.0-beta1

People are worried about Types. ?

js.spec: clojure.spec for JavaScript
Spectrum, static analysis for spec has a new release with a bunch of fixes
Schema & Clojure Spec for the Web Developer
Spec and code organisation

Foundations.

15 Years of Concurrency by Joe Duffy
How to select the most free core?
JVM heap size and its effect on throughput vs maximum response times
Building machines that learn and think like people

Tools.

Replique and reqlique.el, a new Clojure and ClojureScript development environment.
Kibit 0.1.3 is out

Recent Developments.

CLJ-1912: Optimised versions of the ‘<’ and ‘>’ functions for arities larger than 2.
CLJ-1952: include var->sym in clojure.core

Learning.

Reduce Mini-Course from PurelyFunctional.tv
Deep learning with Cortex and Clojure
Creating custom effects in re-frame
A talk about destructuring

Misc.

The always excellent Julia Evans with “Anatomy of a packet”, with more available at drawings.jvns.ca.

22: Thanks for Clojure, Underscores, and Java 9

Sat, 26 Nov 2016 10:23:50 +1300

-main

Arachne Community Update 4
Component vs. Mount was shaping up to be the great Clojure debate of 2016, but things have been quiet recently. Here is the creator of Mount with No Ceremony. I didn’t personally find the arguments very convincing but I liked thinking critically about it.
Running Investor Metrics on Mattermark company scores
Is it always safe to read a string and convert it back to a string? (nope), with a follow-up Klipse demonstration
Alex Miller says thanks for using Clojure
Clojure, Java 9, and you

Libraries & Books.

psq.clj 0.0.2 - Persistent Priority Search Queues
maxiphobe 0.0.1 - Persistent Meldable Priority Queues

People are worried about Types. ?

clojure.spec humane error messages

Foundations.

Quadratic performance of Rust hash iteration + reinsertion
Underscore is a keyword in Java 9
Java SE 8u111 released with some crypto changes

Tools.

IntelliJ 2016.3 is out. The parameter hints look useful, hopefully Cursive can take advantage of them.
Productive Emacs: refactoring Clojure code with clj-refactor
Lumo hits 1.0.0.

Recent Developments.

Clojure infrastructure update from Alex Miller
ASYNC-40 Do not transform forms that have :no-transform metadata attached (not so new, but I came across it recently)
CLJS-1816 adds compiler timing info

Learning.

Clojure Israel is hosting an event with the co-author of “The Art of Prolog”, Dr Ehud Shapiro. If you’re interested in making the trip or want more info, feel free to contact Daniel Szmulewicz. It sounds like it would be worth the trip if you’re in the area.
EuroClojure 2016 Review
Clojure Remote is introducing speaker profit sharing

Misc.

Pragmatic Press has 40% off books this weekend, including some great Clojure ones

21: Hello Clojure, Now What?

Fri, 18 Nov 2016 21:22:52 +1300

-main

A post on logging by Juxt Pro
ClojureScript saved me 100 hours
David Nolen: Now what? along with the rest of the videos from EuroClojure

Libraries & Books.

Clojure Programming Cookbook was released
Perseverance: flexible retries for Clojure
Pegasus: A Clojure DSL for Web-Crawling
hara .security - making sense of the Java Cryptography Architecture
Invariant 0.1.0 - Invariants on Clojure Data Structures
lucidity 1.2.8 deployed

Tools.

Hello Clojure. Hello Cursive. FWIW, Cursive has also been rock solid for me. Upgrades are easy and I haven’t spent any time thinking about or maintaining my Cursive config.

Recent Developments.

CLJ-1107 ‘get’ should throw exception on non-Associative argument
CLJ-1860 0.0 and -0.0 compare equal but have different hash values

Learning.

Island generation

Misc.

code.nasa.gov performance audit

20: Vote for Clojure, Martians, and Puppets

Mon, 14 Nov 2016 09:55:55 +1300

-main

Lumo - The fastest Clojure REPL in the world by Antonio Monteiro (who is getting to be a regular feature in this newsletter)
Alex Miller talks about the Clojure ticket voting process.
Advanced Martian by Juxt explores their open source Swagger HTTP API client
Clojure at Puppet. This was interesting to me as I’d known Puppet were Clojure users for a while but had never heard their backstory.
What AppCanary will miss after leaving Clojure. I’ll be interested to hear the talk they gave about why they chose Ruby.

Libraries & Books.

Why Exponent on React Native is a good fit for ClojureScript
Postgres notifications with Luminus
Using effects in re-frame
Unified storage IO in Replikativ

People are worried about Types. ?

No type worrying this week from the Clojure community, but our neighbours in Elm Town have been having some discussions.

Foundations.

Timothy Pratley is looking for people to join his research group. They cover many different interesting topics.

Tools.

Liquid is a new text editor written in Clojure

Recent Developments.

Discussion about the naming of the any? function in Clojure 1.9
Clarification on # as a valid symbol character, and the related ticket CLJ-1527
CLJS-1128 “Describe internationalization strategies via Google Closure on the wiki” would be a good opportunity for someone looking to start contributing to ClojureScript.
CLJS-1194 adds support for data_readers.cljc

Learning.

(:brno clojure ) is a new Clojure Meetup in Brno, Czech Republic
A recap of EuroClojure 2016

Misc.

Bryan Cantrill gave a talk at Structure 2016 the day after the US election about how technology is disrupting other industries, and the current and future job losses that are going to take place.

19: Dungeons, buttery smooth emacs, and volatile reads

Sun, 06 Nov 2016 21:26:29 +1300

-main

Waste in IT
Procedural Dungeon Generation in ClojureScript
Assimilating with Clojure by Sarah Sunday

Libraries & Books.

Learn Onyx in the browser

People are worried about Types. ?

Clojure 1.9.0-alpha14 is out
Deconstructing Haskell’s Haxl in Clojure

Foundations.

How expensive is a volatile read?

Tools.

Darwin keeps up his blistering pace of development with dirac 0.8.0
Howard Lewis Ship on S cripting in Clojure using Boot
Buttery Smooth Emacs

Recent Developments.

core.async behaviour with timeout 0 and ASYNC-137
CLJ-1435: numerator and denominator fail to handle integral values
CLJ-2041: clojure.spec/keys requires input collections conform to clojure.core/map?

Misc.

Alex Payne - What Pro Computing Could Be and Reid McKenzie’s Of Inertia and Computing, both touch on similar themes.

18: re-frame coeffects, nice error messages, and broken software

Fri, 28 Oct 2016 22:09:30 +1300

-main

Clojure in Greece
New Orleans Clojure Workshop Retrospective - I really enjoyed how open Eric Normand was about running the workshop, what went right, and what went wrong.
A good explanation of coeffects in re-frame, and why you might want them

Libraries & Books.

superv.async 0.2.1 is out. There’s also a good rationale on its Erlang inspired error handling model.

People are worried about Types. ?

Arachne Community Update 3 showcases some really nice looking error messages using spec.
Static typing will not save us from broken software

Tools.

A Clojure REPL workflow for beginners
Modified Gorilla REPL 0.4.0 (a fork?) has been released

Waiting for 1.9.

CLJ-1451 Add take-until function
CLJ-1544 AOT namespace loading
CLJ-2049 Improve clojure.zip documentation

Learning.

Eric Normand also has a new course Beginning with Clojure Macros, and the first 2 videos are free to watch.
How to write a custom Kerodon matcher (for browser integration testing)
Core.match interactive tutorial
CircleCI’s ClojureBridge experience report

Misc.

Precursor (a ClojureScript prototyping tool) is now open source

17: Clojure on a plane, Onyx in a browser

Sat, 22 Oct 2016 08:48:11 +1300

-main

Updating diagnostics for Boeing’s 737 MAX (using Clojure)
Clojure is not afraid of the GPU

Libraries & Books.

Tengen, a macro for making Reagent components a little easier from Peter Taoussanis. Most of the time form-1 and form-2 Reagent components are all I need, but this is worth looking at if you need to work with the React lifecycle methods more deeply.
Tempura, an internationalisation library also from Peter Taoussanis.
onyx-local-rt has been released, a way to run Onyx systems locally, and even in the browser (!)
ClojureScript 1.9.293 is out, it’s great to see Antonio Monteiro’s contributions.
clj-xchart, a charting library for the JVM has been released, with excellent docs.
graphql-clj: A Clojure library that provides a GraphQL implementation
carry: A ClojureScript web app framework
Sextant: Offline geocoding in Clojure

People are worried about Types. ?

Colin Fleming with some research on the capabilities and requirements for type systems that interop with Java
Typed X just doesn’t pan out?

Tools.

Adding a new language to Emacs

Waiting for 1.9.

CLJS-1762: Bump Closure Compiler
CLJS-844: Optimize js->clj by switching to transients
A discussion on the mailing list about strange behaviour of js->clj in advanced compilation mode

Misc.

An excellent guide on AWS, you’re bound to pick up a trick or two, even if you’ve been using it for a while.

16: Clojure is boring, Ethereum is exciting, and podcast scoops.

Sat, 15 Oct 2016 10:11:13 +1300

-main

Reflecting on XT16
Colin Jones with a bold assertion that Clojure is boring
Datomic web apps: a practical guide

Libraries & Books.

A new library for managing Permissions
Arachne Community Update 2
Tracks is a library from Bryan Maass for declarative data manipulation. That sounds a bit boring, but check out the README, because it can do some pretty cool stuff!
re-com 1.0.0 is out
Cortex: A machine learning library for Clojure, has recently been open sourced, with more discussion on the Clojure mailing list
zprint: A new (alpha) library for reformatting Clojure source code

People are worried about Types. ?

Custom defn macro with clojure.spec: part 1, and part 2.

Foundations.

A gentle introduction to Prolog, and The Clojure Atom has some more linksto Prolog tutorials
In the discussion about machine learning for Clojure, Dragan Djuric had a particularly insightful post on high performance matrix operations.

Tools.

Just when you thought it was safe to go back in the REPL, Zach Oakes releases Nightlight.
Cider 0.14 (Berlin) has been released

Waiting for 1.9.

The defn podcast interviewed Alex Miller, and scooped some things about Clojure’s development I hadn’t heard before, including that there may be more features coming to Clojure 1.9, and that it is unlikely to be released this year.
CLJS-1817 fixes a bug in the PersistentHashmap implementation
ASYNC-159: promise-chan is broken in ClojureScript

Learning.

XT16 conference notes
Lambda Island on using JavaScript libraries in ClojureScript
How to create decentralised apps with ClojureScript, re-frame, and Ethereum
How we test our full-stack Clojure app
Clojure and AWS Serverless, an introduction

15: Better error messages, the Clojure curve, and the Worlds Worst Singles Network

Fri, 07 Oct 2016 09:43:16 +1300

-main

Clojure in the UK: Funding Circle
Single use tokens in Datomic with the Worlds Worst Singles Network
TDD in ClojureScript with Devcards

Libraries & Books.

better-cond, a version of cond that supports :let clauses, and it’s rationale
Chris Zhang introduces hara.zip
core.matrix is moving into Clojure contrib
Expectations is being re-launched to support tooling that integrates with clojure.test
pulley.thread-local - an atom like interface for local thread bindings
core.async top use cases

People are worried about Types. ?

Tools.

Clojars is getting a CDN (testers needed)
Cloverage is now in a new GitHub organisation and is seeing new releases.
Sourcemaps providing sourcesContent

Waiting for 1.9.

An interesting discussion on extending clojure.lang.Numbers
Add 0 and 1 arity to into
CLJS-1807: Better error messages for ns* calls
CLJS-1796: Measure Google Closure optimisation time

Learning.

CircleCI are hosting a ClojureBridge in San Francisco on October 21-22

Misc.

Clojure and the Curve

14: Martians, union types, reusable components

Sat, 01 Oct 2016 09:42:17 +1300

-main.

There were some interesting discussions this week on Clojure mailing lists: parallel sequence side-effect processor, Idiom question (on threading macros), graphql/relay for reagent?
Reusable Components
Martian: an HTTP client that uses Swagger definitions
Om Next incremental rendering

Libraries & Books.

Arachne community update
tappit: Test Anything Protocol for Clojure
data-frisk-reagent visualises Reagent app data in tree form
re-frisk takes this to the next level if you are using re-frame
data-scope visualises Clojure data (on the JVM)

People are worried about Types. ?

Union Types with Clojure.Spec, including a macro that does compile time checking that all of the specs are matched on. I’m very excited about the possibilities for this.
David Nolen’s talk at Papers We Love on Parsing With Derivatives is up on Youtube
Spec vs types questions on Reddit with some good answers from Alex Miller
Stuart Halloway on Agility & Robustness from his talk at Strange Loop last week
Clojure 1.9.0-alpha13 is out

Foundations.

AOT compilation is coming to Java 9

Learning.

In/Clojure 2016, the first Clojure conference in India has a CFP open and tickets available.

13: Strange Loop, Clojure In Europe, Datomic in production

Sat, 24 Sep 2016 11:26:19 +1300

-main.

Paul Stadig on The System Paradigm
JUXT are starting a series called “Clojure In”, exploring Clojure in industry across Europe, starting with Aviso and uSwitch.
Alistair Roche on Datomic in Production

Libraries & Books.

Monger 3.1.0 is released
cljs-oops, a native JS object access lib has released 0.2.0.

People are worried about Types. ?

Stuart Halloway gave a talk at Strange Loop “Agility & Robustness: Clojure spec”.
How to declare all valid keys in a map which is a problem I’ve hit already in early spec adoption.
David Chelimsky from Cognitect talks about spec at Chicago Clojure.

Foundations.

Google has created a new TCP congestion control algorithm which is pretty neat (and the explanation is very readable). The patch is here, and there will be an ACM Queue article soon.
Project Jigsaw in JDK 9, another Strange Loop talk

Tools.

Clojars is moving to Linode, and needs your help to make sure nothing breaks for you. See the announcement for testing instructions.
Alexander Yakushev has released ns-graph has released a tool for graphing ns dependencies

Learning.

PurelyFunctional.tv has an FP programming career guide

Waiting for 1.9

CLJ-1906: Clojure should make representing iterated api calls easier, more discussion at clojure-dev.
7ff4c70: Fix notable conformance in Clojure Spec
CLJS-1785: Warn on reference to js/foo shadowed by local binding
CLJS-1775: get with nil returns as if get with 0
CLJ-787: transient blows up when passed a vector by subvec
CLJ-2026: Transient exceptions thrown in clojure.spec.test/check

Misc.

One more Strange Loop talk: Aysylu Greenberg on building a distributed build system at Google scale.

12: False sharing, riddles, specs

Sat, 17 Sep 2016 19:53:20 +1300

-main.

Implementing leaky channels with core.async
David Nolen’s talks about the last five years of ClojureScript at ClojuTRE. More videos from the conference are on Youtube.
develop, test, communicate by Chris Zheng. I always enjoy Chris’s writing and work because it comes with a very distinct philosophy. I think this piece captures that philosophy.
Solving a not-so-easy riddle
Good discussion on the sequence paradigm in Clojure, particularly from Alex Miller. See a similar discussion on derefing nil.

Libraries & Books.

🎉Reagent 0.6.0 is out 🎉
hara.io.file, a NIO file library by Chris Zheng
Om Next Server-Side rendering

People are worried about Types. ?

Combining specs with s/or by Alex Miller
Arne Brasseur’s gave a talk at ClojuTRE on clojure.spec, and published his slides
Paul Chiusano with a refreshingly level headed take on static vs dynamic typing.
Using clojure.spec to declaratively parse query parameters

Foundations.

Gotta go fast with Netty
A Funny Thing Happened on the Way to Java 8. A cautionary tale of JVM tuning. Worth keeping in mind with Java 9 coming out soon.
Gil Tene on false sharing.

Tools.

How We Test our Full-stack Clojure App
Cider now displays specs in doc buffers

Learning.

Core Async and Transducers
ClojureBridge Pittsburgh experience report
CfP for :clojureD 2017

Waiting for 1.9.

CLJS-1770: goog-defines now work for integers
CLJS-1773: Don’t resolve unqualified symbols/keywords with $macros, which contains a good explanation of macro namespaces in ClojureScript.

Misc.

A beautiful post On Generative Algorithms

11: Shootout's, benchmarks, and cryptocurrencies

Sat, 10 Sep 2016 10:32:22 +1300

Articles.

Libraries & Books.

Clojure Polymorphism, a short book about, well it’s in the title.
cuerdas 1.0.0, a Clojure(Script) string manipulation library
manifail 0.4.0, Manifold failure handling
banach, more Manifold failure handling
shapeshifter, a way to l̶a̶u̶n̶d̶e̶r̶ convert your cryptocurrencies

People are worried about Types. ?

Closable services
The Ergonomics of Type Checking
Clojure 1.9.0-alpha12 is out
Generatively testing UI state with spec and devcards is an awesome idea
Spec has vaulted itself towards the top of the validation benchmark league tables in alpha12

Foundations.

A minimal JVM Value Types proposal for prototyping/evaluation
How the JVM compares your strings, a.k.a. How Intel improved string comparisons with this one weird instruction.
Contention on sun.misc.Cleaner

Tools.

The Google Closure Compiler is now cross compiled to JavaScript

Waiting for 1.9.

spec perf tweaks 1, 2
coll-of now handles sequences - CLJ-1988
Records now cache hasheq and hashCode - CLJ-1224
Discussion on CLJ-322: Enhance AOT compilation process to emit classfiles only for explicitly-specified namespaces.

Learning.

A long awaited return to Aphyr’s Clojure From The Ground Up series: State
ClojureBridge Berlin has a cool new website
Applying Clojure
Martin Klepsch on desktop apps with ClojureScript and Electron

10: Ultimate REPLs, opinionated na's, pluggable printers

Fri, 02 Sep 2016 11:00:25 +1300

Intro.

This week there’s a new section, suggested by Colin Taylor: Waiting for 1.9, which highlights JIRA tickets and commits of interest.

Articles.

The Ultimate Guide To Clojure REPLs, and looking at the table of contents, I don’t think that title is an exaggeration.
Stuart Sierra’s opinionated ns style guide

Libraries & Books.

Jake McCrary has released reload, a Ring middleware for reloading your namespaces with clojure.tools.namespace on every request.

People are worried about Types. ?

Functional Mumbo Jumbo - ADTs by Kris Jenkins
core.typed now has support for generating specs from unit tests
clojure.core specs can be consumed by external projects safely

Foundations.

ObjectLayout, a set of data structures that could be used to support higher performance for object arrays by allocating contiguous memory in a hypothetical future JVM. See also this presentation on it.
Project Valhalla, a similar but more ambitious project for value types in Java.
A mailing list discussion on how these two projects relate, including an excellent reply by Brian Goetz with a 20 year future perspective on Java’s development.

Tools.

Colin Fleming has released a plugin to c ompile Clojure with Gradle, if you’re into that kind of thing…

Waiting for 1.9.

Make clojure spec explain printer pluggable
It looks like there’s movement on CLJ-700, contains? broken for transient collections
Not all keywords that can be printed can be read. This comes up now and again, so it’s worth remembering.
Protocolize CLJS compiler access to the file system

Learning.

Alex Miller will be teaching a half-day spec workshop

Misc.

Incidents involving the CA WoSign

9: spec, parsing with derivatives, and black magic

Sat, 27 Aug 2016 10:21:27 +1300

Notes.

No newsletter last week as I was on holiday, but this one is a bumper spec issue.

People are worried about Types. ?

I’m putting this section at the top this week, as there are several important spec related links.

A lively thread on spec error messages
Clojure 1.9.0-alpha11 is out which includes specs for clojure.core
core.typed basics of automatic annotations, and inferring function types
Om next and Bootstrapped ClojureScript
Focus on spec: Combining Specs with and from Alex Miller

Foundations.

More spec, but this time in the foundational section, several papers that influenced spec’s design. David Nolen spoke on this at Papers We Love NYC, I’ll be sure to post the video if it was recorded.

Parsing with Derivatives
On the Complexity and Performance of Parsing with Derivatives
Matthew Might talks about parsing with derivatives

Articles.

I was sad to hear Yeller was shutting down
Onyx raised $500k, congratulations!
Daniel Higginbothams writing process
Datomic’s log API

Learning.

Tetris in ClojureScript with an impressive way to interact with the running code.
Nathan Marz talking at ClojureNYC on inline caching to speed up Clojure programs

Libraries & Books.

clojure.data.avl has a new release
Shrubbery 0.4.0, a stubbing, spying, and mocking library for Clojure protocols
re-frame has a massive new release out with a ton of cool features. I contributed to this release, and am really looking forward to seeing how people use it.

Tools.

s trace’ing a Clojure process under lein
Leiningen 2.7.0 was released, managed-dependencies looks like it could be really useful.
Funcjure (not yet released) brings infix notation to Clojure. Not to my taste, but interesting nonetheless.
Cloverage has a new release thanks to LVH.

Misc.

More black magic from Zach Tellman

8: Recursion, automatic annotations, more recursion

Sat, 13 Aug 2016 09:18:30 +1300

Articles.

Generating Sight-Reading Exercises using Constraint Logic Programming in Clojure
Fun vs. Computer Science, not strictly a Clojure article, but it talks about iterative development which is always relevant.
Understanding recursion
More recursion with Y Combinators
More Y Combinators

Libraries & Books.

System 0.3.1 is out
ClojureScript 1.9.198 is out with support for renames in the ns form from António N. Monteiro
Transforming data with ClojureScript a book about … well you get the idea.

People are worried about Types. ?

Automatic Annotations for Typed Clojure, c.f. Reddit comments
An Indiegogo fundraiser for Ambrose Bonaire-Sergeant to continue working on Typed Clojure
Spectrum is a library from Allen Rohner, for doing static analysis of Clojure code, catching clojure.spec conform errors at compile time.
A spec screencast on Customising Generators by Stuart Halloway
Focus on spec: Predicates by Alex Miller

Foundations.

Benchmarking the cost of primitive operations on the JVM

Tools.

Monroe 0.3, an Emacs nREPL client for Clojure has been released

Learning.

Video of a Workshop on Rum, a ClojureScript React library
Walkthrough of a re-frame app
Clojure Conj 2016 has been announced for December 1-3, in Austin, Texas
Why do all libraries have a core package?

Misc.

Kyle Kingsbury’s distributed systems lecture notes

7: One million 4Clojure problems solved, the origins of complect, and some Clojure-Fu

Sat, 06 Aug 2016 01:15:32 +1300

Articles.

Klipse for Kids
Macros for straightforward parallelism in Clojure, a thesis by David Zmick
Clojure-Fu with juxt
The Clojure Atom on re-frame

Libraries & Books.

People are worried about Types. ?

Michael Nygard has a good article on The Perils of Semantic Coupling. It’s particularly relevant in light of people starting to model their domains with spec.

Foundations.

John Rose on premature optimizations
Fixing Coordinated Omission in Cassandra Stress
From Concurrent to Parallel by Brian Goetz
Compact Strings in Java 9

Tools.

Do you use any Clojars data feeds?
cljs-devtools released version 0.8.0. I 100% recommend using cljs-devtools if you’re developing with ClojureScript.
Cloverage project status, looking for new maintainers
Enjoy scripting with Clojure

Learning.

4Clojure hits 1,000,000 problems solved
EuroClojure call for presentations closes any minute now

Misc.

Rich Hickey on the origins of complect, and his suggestion to use ‘simplified’ instead of ‘decomplect’.

6: Delays, Promises, Onyx, California Cider

Sat, 30 Jul 2016 06:48:41 +1300

Articles.

People are worried about Types. ?

Foundations.

Two very extensive articles about the Java Memory Model by Aleksey Shipilёv.

Tools.

Cider 0.13 California is out
Two new clojure emacs libraries: helm-cider, and cider-hydra
Two years of Eve by Chris Granger of Light Table fame

Learning.

The importance of fun in our work - XT16, a Clojure conference by Juxt
Thinking Functional With Clojure workshop at DevoxxUK 2016
What do I have to learn to be hirable in Clojure?
Just got my first Clojure job! Any tips for someone using it in production for the first time?

Misc.

Lambda Calculus 1 and 2 from Klipse, with their impressive inline bootstrapped ClojureScript compiler.

5: Emacs in space, Clojure is my moon.

Sat, 23 Jul 2016 16:21:44 +1300

Articles and Talks.

Emacs in space, but with a sci-fi novella in it.
Clojure Is My Moon by Nola Stowe, who you can also thank for the new string functions in Clojure 1.8
David Nolen - How To Win Big With Old Ideas
What Template Haskell gets wrong and Racket gets right (about macros)
How To Rapidly Improve At Any Programming Language

Libraries & Books.

Repetition Hunter
one-time, One Time Passwords for 2FA
From Onyx Template to Working App in Thirty Seconds
Tongue, a do-it-yourself i18n library for Clojure and ClojureScript.

People are worried about Types. ?

Clojure Spec, performance and workflows discussion on Google Groups with a detailed response from Rich Hickey
Genetic Programming With clojure.spec

Foundations.

How to get better at mechanical sympathy
An article about Graal & Truffle, a really exciting project with a bunch of great features for implementing languages with high performance on top of the JVM.
Fogus: Linkage 002

Tools.

Open Letter to the Emacs Maintainers
Bruce Hauman takes donations to help fund Figwheel and Devcards, two indispensable tools in the CLJS community. I’ve donated, I’d encourage you to do so as well if you find it useful.

Learning.

A Clojure Newbie Guide
Elements of Clojure, a book by macrologist Dr Zachary Tellman is in preview.
Web Development with Clojure, Second Edition is out. Reddit.
Stack Overflow documentation for ClojureScript and Clojure. Should we use it though?
Reagent: Keys and lifecycle methods by Lambda Island

Misc.

re-frame has a new logo thanks to Martin Klepsch

4: Cursive and Light Table have a baby, Scala gets slower, byte handling gets faster

Sat, 16 Jul 2016 09:56:45 +1300

Intro.

Welcome to another week of The REPL. If you have any links you’d like me to share, please send them through. Onward!

Articles.

LVH on Crypto APIs and JVM byte types
James Reeves explaining the Async Ring proposal
A 34 line code change in the Scala compiler caused a 20% performance decrease. This was a reminder to me of the benefits of Clojure’s conservative development and the importance of profiling.

Libraries & Books.

Which leads me to Tufte, a simple profiling and performance monitoring for Clojure/Script
I have spent much of my time as a computer programmer scraping blind in the dust. Now I recline, keenly sighted, on furniture of criminal opulence.

People are worried about Types. ?

Foundations.

Allocation on the JVM: Down the rabbit hole

Tools.

AWW HELL YEAH, GONNA BE LIKE LIGHT TABLE HAD A BABY WITH CURSIVE, HAHAAAAAA!
Cursive 1.3.0 released
Halik, the time travelling debugger, now with experimental Clojure support
eftest, a fast and pretty Clojure test runner

Learning.

Call for Speakers: London Clojurian Conference
Clojure News: A Hacker News clone

Misc.

Kyle Kingsbury uncovers problems with VoltDB 6.3, nice to see they were able to fix them in 6.4

3: Odin, Onyx, and more Clojure alphas

Sat, 09 Jul 2016 06:00:47 +1300

Intro.

When I started writing this a few weeks ago, I worried that there wouldn’t be enough to fill up a whole newsletter. But there’s so much going on at the moment in Clojure that I needn’t have worried.

Articles.

Hello World for the Next Generation by Carin Meier, a touching piece on the power of code.
Edge: A complete Clojure project you can leap from with autoloading cljs, Component integration, and boot setup. Edge uses Yada. Here’s an example resource definition for those curious about Yada.
Onyx 0.9.7: How We Handle High Risk Design Changes. A high level look at how the Onyx team used test.check and Jepsen to shake out bugs while doing a major refactor.
thi.ng show us how to use ClojureScript, WebWorkers, and WebGL

Libraries & Books.

The Clojure alphas will continue until m̶o̶r̶a̶l̶e̶ spec improves. Just kidding of course, spec is coming along well.
Ring 1.6.0 beta 2 was released this week with async handlers support. More discussion on Reddit.
bette r-cond, a version of cond that supports :let and :when-let clauses
Mutant: mutation testing for Clojure
Akar, first class patterns for pattern matching with an extensive tutorial and FAQ
Arachne’s retrospective and risk assessment.

People are worried about Types.

Carp, a statically typed lisp without GC, modelled on Clojure.
Method missing patch for Clojure

Foundations.

Tools.

ClojureScript namespace aliasing will make it a lot cleaner to write cross platform code using libraries like core.async and spec.

Learning.

Timothy Baldridge builds Odin, a DSL for logic programming in Clojure
Tickets are on sale now for EuroClojure 2016
The first issue of The Clojure Atom by Brave Clojure
Afterglow: Live Coding for Light Shows by James Elliott
The Ultimate Guide to Learning Clojure for Free

Misc.

Expert to Expert: Erik Meijer and Rich Hickey

2: What is symbolic computation? Let your applications die hard, Async ring.

Sat, 02 Jul 2016 10:24:48 +1300

Intro.

The biggest Clojure news this week was the release of Clojure 1.9.0-alpha8. We’re starting to investigate spec at work, and things are looking good so far. When I first saw spec, it made some choices that I thought were “wrong”. I’ve come around on those in the last few weeks as I’ve seen how they could have prevented some issues we had when using schema. Turns out Rich knows what he’s doing 😄.

Articles.

What the Hell is Symbolic Computation? by Steve Losh. This gets down into the nitty gritty of how a Lisp REPLs, and how quoting and symbols work. I found this really interesting.

Discussions.

Proposal: Asynchronous Ring, State of Ring CPS, and the Reddit discussion are all worth reading if you’re interested in asynchronous Ring. Paul deGrandis in particular had some really good perspective on how Pedestal Interceptors work, and the benefits of the Pedestal approach.
Colin Fleming’s comments around nil handling on the Reddit discussion for How many of Java’s horrors are addressed by Clojure?

Libraries & Books.

diehard is a Clojure wrapper over Failsafe. It’s designed for handling failures and retrying in your programs. Apart from what it does, I just like the name.
Immutant 2.1.5 was released, with same day support for the newly released JBoss EAP 7.
Arachne development update and schedule
Nikita Prokopov has backported spec to Clojure 1.8 in clojure-future-spec.

People are worried about Types.

Bruce Hauman has valiantly created a 1,000 line spec for ClojureScript compiler options which including validation for complex co-dependencies.
How Elm Slays a UI Antipattern from the always excellent Kris Jenkins.
Property-Based Testing with Clojure and Datomic, part 2
5 Differences between clojure.spec and Schema

Foundations.

Learning.

Tim Baldridge has moved his excellent series of Clojure videos from Pivotshare to Youtube. Some are free, and some are paid. They’re all well worth watching for expert level insight into core.async, transducers and other advanced Clojure topics. 2019 Update: This has moved back to Pivotshare due to Youtube shutting down paid channels.

Misc.

Kyle Kingsbury breaks a database based on Elasticsearch, news at 11.

1: Alan Kay vs Rich Hickey, Static vs Dynamic, The Great Startup Problem

Sat, 25 Jun 2016 13:09:51 +1300

Intro.

Welcome to the first issue of The REPL. The REPL will cover what’s happened in the Clojure world recently, relevant links from slightly wider afield, and some older things that are still great.

Libraries & Books.

Professional Clojure: The Book was released recently. Michael Gaare talked about the section he wrote on Datomic.
One of the limitations of cljc compared to cljx was that cljc wasn’t backwards compatible with older version of Clojure. Alex Engelberg’s cljsee lets you preprocess cljc files into platform specific clj and cljs files.

People are worried about Types.

This section is inspired by Matt Levine’s ongoing sections on “People are worried about bond market liquidity”

“Static vs. Dynamic” is the wrong question.
Validation Benchmark shows Truss way out in front, Schema close behind, and Annotate, Herbert, and Spec are much slower. I’m not 100% sure that these results are accurate, so do your own due diligence.

Articles.

Malcolm Sparks talks about Concerns with Ring and compares and contrasts it with Yada. Yada was interesting to me before, but this article gave some more tangible reasons for why I might want to consider it. There was some good discussion on Reddit (!) about this, with James Reeves giving his perspective as a core author/maintainer of the Ring ecosystem.

Foundations.

The Great Startup Problem, a mailing list post by JVM Architect John Rose about Invokedynamic, JVM startup, and JVM warmup. Very technical, but worth reading even if you don’t understand all of it. H/t to Ghadi Shayban for the link.
Heroku’s T roubleshooting Memory Issues in Java Applications is a good intro to profiling Java memory issues, even if you’re not running on Heroku.

Tools.

Instant Clojure REPL startup (with some sneaky tricks).
Planck, a ClojureScript REPL now runs on Linux.
More Boot
The defn podcast takes a Tour of the REPLs with Mike Fikes

Learning.

Daniel Higginbotham (of Clojure for the Brave and True) has started offering on-site training, and published his training materials.
Jonathan Graham is offering a (presumably free?) webinar about understanding how core Clojure functions work. More info here.

Misc.

Don’t miss Alan Kay and Rich Hickey on Hacker News. ‘What if “data” is a really bad idea?’