Haskell Weekly


Issue 104 2018-04-26

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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.

Want to see something featured in Haskell Weekly? Open an issue or pull request on GitHub.


  • GHC 8.4.2 released

    The GHC team is pleased to announce the availability of GHC 8.4.2. This release is a bug-fix release, fixing numerous regressions and bugs present in GHC 8.4.1.

  • Summer of Haskell: Accepted projects for 2018

    We are happy to announce the 17 projects that have been accepted to participate in Google Summer of Code 2018 for the Haskell.org project. We would like to thank Google for organizing the program, all students who applied for the quality proposals of course the mentors for volunteering to guide the projects!

  • Funflow: Typed resumable workflows

    Funflow is a system for building and running workflows. It’s a system we’ve been working on for the last few months with a small number of clients. In this blog post we’ll talk about what workflows are, why we built Funflow, and what we’d like to do with it in the future.

  • Program reduction: A win for recursion schemes

    However, despite my enchantment with the beautiful theory — and especially it’s connections with category theory — it took a while before the promise of these abstraction really paid off. And pay off it did.

  • Uncanny Haskell

    Below, I have collected several examples of “uncanny” Haskell. These are things that may be surprising to those who have learned the language merely by doing.

  • Making a text adventure in Haskell: Part 4

    In this final post about my text adventure engine, I’ll describe how I updated the state of the game world and how to use the HaskellAdventure game engine to create a full text adventure game.

  • Deploying confidently: Haskell and Circle CI

    Wherever there are manual steps in our development process, we’re likely to forget something. This will almost always come around to bite us at some point. In this article, we’ll see how we can automate our development workflow using Circle CI.

  • Path count

    Given two integer numbers describing an n by m graph, where n represents the height and m represents the width, calculate the number of ways you can get from the top left to the bottom right if you can only go right and down.

  • Null object as identity

    In a previous article you learned how there’s a strong relationship between the Composite design pattern and monoids. In this article you’ll see that the Null Object pattern is essentially a special case of the Composite pattern.

  • The HolidayCheck apprenticeship

    At HolidayCheck we want to consciously and explicitly invest in people. We believe that one of the best possible outputs to be generated by Senior Engineers are more Senior Engineers.


  • Software engineer at ITProTV in Gainesville, Florida

    ITPro.TV is a fast-growing digital media business that focuses on continuing education in technical domains. We are currently accepting applications for full-stack software professionals to join our small but talented multidisciplinary team.

In brief

Package of the week

This week’s package of the week is Hspec, a testing framework inspired by Ruby’s RSpec library.

Call for participation


  • April 27-29: BayHac 2018 in San Francisco, California, United States