Haskell Weekly


Issue 206 2020-04-09

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Welcome to another issue of Haskell Weekly! Haskell is a safe, purely functional programming language with a fast, concurrent runtime. This is a weekly summary of what’s going on in its community.


  • Common JSON patterns in Haskell, Rust and TypeScript by Christian Kjær

    In TypeScript/JavaScript this is straightforward, since JSON is built into the language. But can we also achieve good ergonomics in Haskell and Rust?

  • Dealing with Friday the 13th by Tom Sydney Kerckhove

    The fuzzy-time library and its cursor cursor-fuzzy-time allow humans to enter time data with ambiguities and context and have them translated into actual timestamps using good guessing and confirmation from the user.

  • DWARF support in GHC (part 5) by Ben Gamari

    This is the fifth and final post of a series examining GHC’s support for DWARF debug information and the tooling that this support enables.

  • Introduction to GHC language extensions by Type Classes

    This course covers the ones we think are most likely to be useful and helpful to the Haskell beginner or early intermediate as well as a few having to do with issues that crop up whether you’re ready for them or not.

  • Lessons in Managing Haskell Memory by Fabian Thorand and Yorick Sijsling

    This time, we are going to describe our journey of getting Haskell garbage collection times under control when dealing with heap sizes of up to 100 GB per instance.

  • The Power of Tiny DSLs by Jack Kelly

    This means I have to compute the transformation twice: once as codeworld-api calls, and once as matrices. Or do I?

  • RecordDotSyntax language extension proposal by Simon Peyton Jones

    As the shepherd for this proposal, I’m happy to say that the GHC Steering Committee has, finally, come to a conclusion: we accept the proposal, subject to final revisions, with some additional specifics about syntax.

  • A Telegram bot in Haskell on Amazon Lambda by Joachim Breitner

    This led me to learn about how I write a Telegram bot in Haskell and how I can deploy such a Haskell program to Amazon Lambda.

  • Wide Haskell: Reducing your Dependencies by Colin Woodbury

    This post describes my recent experiments in actively reducing the number of depedencies in my Haskell projects to achieve a “wide” (not deep) dependency graph.

  • X-Ray and WAI by Magnus Therning

    As a first step I implemented a WAI middleware that wraps an HTTP request and reports the time it took to produce a response.


  • Interos is Hiring Full Stack Haskell Software Engineers (ad)

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Trying to hire a Haskell developer? You should advertise with us!

In brief

Show & tell

  • BerylliumBlueberry by Chris Stryczynski

    A simple blogging software using Scotty, Lucid and Postgresql-orm.

  • coercible-subtypes by Koji Miyazato

    This library provides unidirectional (one-way) variant of Coercion.

  • smash, smash-lens, smash-microlens, smash-aeson by Emily Pillmore

    The core library, smash, contains some really interesting datatypes that I’ve been staring at for a while now while musing about the These datatype.

Call for participation