Haskell Weekly


Issue 181 2019-10-17

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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.


  • Beating C with 80 lines of Haskell: wc by Chris Penner

    The challenge is to build a faster clone of the hand-optimized C implementation of the wc utility in our favourite high-level garbage-collected runtime-based language: Haskell!

  • A Summer of Runtime Performance by Andreas Klebinger

    GHC produces pretty fast code by most standards. After Well-Typed put some development effort towards faster code it’s now even faster, with a reduction in runtime of 3-4%.

  • Haskell in Production by Felix Mulder

    During the past year, my team has been building production services using Haskell. It’s been quite a journey. None of us had written production code using Haskell before.

  • GHCi :set command by Type Classes

    The :set command can be used to change various behaviors of GHCi from within a running REPL. Options set with the :set command can be undone with the :unset command.

  • Servant’s type-level domain specific language by Brad Parker

    Our aim here will be to understand how Servant can take so many varied API descriptions and guide us to a corresponding implementation.

  • Partial application using flip by Jasper Van der Jeugt

    I have been writing Haskell for a reasonable time now – I believe I am coming up on ten years – so sadly the frequency with which I discover delightful things about the language has decreased.

  • Monads as Graphs by Neil Mitchell

    In the Build Systems a la Carte paper we described build systems in terms of the type class their dependencies could take. This post takes the other view point - trying to describe type classes by the graphs they permit.

  • Ormolu: Announcing First Release by Mark Karpov and Utku Demir

    We’re happy to announce the first release of Ormolu, a formatter for Haskell source code. Some may remember our first post from a couple months ago where we disclosed our work on the Ormolu project — but carefully called it “vaporware” then. Times have changed; it’s not anymore.

  • Record Dot Syntax proposal by Neil Mitchell and Shayne Fletcher

    We propose a new language extension RecordDotSyntax that provides syntactic sugar to make the features introduced in the HasField proposal more accessible, improving the user experience.

  • Refactoring Yahtzee by Haskell Weekly Podcast

    Cameron Gera and Taylor Fausak discuss using types to guide refactoring toward better design.


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In brief

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