Haskell Weekly


Issue 222 2020-07-30

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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.



  • Software Engineer at ITProTV

    ITPro.TV is a fast-growing digital media business that focuses on continuing education in technical domains. We are seeking software engineers to help us build out and scale our next-generation of internal services and customer-facing knowledge and entertainment products.

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

    At Interos, we are disrupting the way Fortune 500 companies and government agencies identify and respond to risk within their supply chains. We deliver the data and insights to business leaders that help them identify, visualize and understand the ripple effects that could impact their supply chains, before they happen. Recently funded by Kleiner Perkins and pivoting to an automated solution, Interos is in essence, a start-up SaaS environment.

  • Haskell developer at Lohmann & Birkner in Freiburg

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

Upcoming events

In brief

  • Announcement/call for contributors: Monpad by George Thomas

    So about six months ago, my flatmate and I got frustrated that we didn’t have enough controllers for the whole gang to play Ultimate Chicken Horse…

  • cabal-install-3.4-rc1 now available by Oleg Grenrus

    The Cabal developers are happy to announce the first release candidate for cabal-install-

  • Codata/Data with Type Classes and Tagless Final Style by Molossus Spondee

    This post isn’t really about tagless final style so I won’t go into too much more detail. Really this post is about Scott encodings.

  • Coerced: new optic kind by Oleg Grenrus

    Combining Coercible and QuantifiedConstraints to define new kind of optics, which I call Coerced.

  • Deriving the Writer monad from first principles by William Yao

    If you didn’t have the Writer monad already implemented for you, how would you go about deriving it from first principles?

  • Fall 2020 Fellowships: Funding for Open Source Contributors by Richard Eisenberg and Matthias Meschede

    We invite professionals, students, retirees, hobbyists, and other individuals to propose projects for funding until September 30th.

  • Functional Programming at LeapYear by Christopher Hockenbrocht

    Haskell, the foundational language for core programs at LeapYear, is up to the task, and delivers fundamental correctness guarantees, security, and efficiency.

  • The golden rule of software quality by Gabriella Gonzalez

    The golden rule is: Prefer to push fixes upstream instead of working around problems downstream.

  • Haskeller Competency Matrix by Alexander Granin

  • How to deal with money in software by Tom Sydney Kerckhove

    After a bit of a rant on twitter, I want to explain what they likely did wrong and how to deal with money correctly.

  • Machine Learning in Haskell by Tony Day

    I don’t code in Haskell to help eliminate bugs. That seems a goal unlikely to produce joy in my code. I write Haskell primarily because in enables me to name things a bit better.

  • A Microservice is a Centralized Effects System by Eliza Brandt

    If you’re running a Haskell backend with a non-trivial amount of microservices, you’re probably using an effect system too.

  • Monads and Mom by Richard Marmorstein

    What if there were some single abstraction that captured this idea of “plumbing” more generally? Wouldn’t it be incredible?

  • Monads Are Just Fancy Semicolons by Marcel Moosbrugger

    Monads are programmable semicolons. That’s it. For a programmer, a monad provides functions that allow for sequencing actions.

  • Neuron 0.6 released by Sridhar Ratnakumar

    Neuron is a note-taking tool based on Zettelkasten, that aims to be future-proof. Version 0.6 just got released.

  • Tutorial: Transparent interfaces in Haskell by Henri Tuhola

    Have you ever wanted to take a JSON object and access it in Haskell with minimal effort of only specifying what you’re expecting from the value?

  • Which packages does Hoogle search? by Neil Mitchell

    This post explains which packages are searched, why some packages are excluded, and thus, how you can ensure your package is searched.

Show & tell

  • composable-sdr by Mariusz Ryndzionek

    DSP processing blocks aimed at SDR, embedded in Haskell.

  • haskell-code-spot by Csaba Hruska

    Visual tool to spot odd runtime behaviour of Haskell programs.

  • isbn by Christian Charukiewicz

    This library provides data types and functions both validating and working with International Standard Book Numbers.

Call for participation