Haskell Weekly

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.

Featured

• Aeson Object Design (Part 4) by Travis Cardwell

  In Aeson Object Design (Part 2), I explored the cost of representing objects with various data structures. Today, I created the benchmarks for the normal scenario.

• Automatically updated, cached views with lens by Brent Yorgey

  Recently I discovered a nice way to deal with records where certain fields of the record cache some expensive function of other fields, using the lens library.

• Browse Hackage from the terminal by Marcelo Lazaroni

  The Haskell ecosystem has great facilities for searching and navigating package documentation using the browser. haskell-docs-cli allows you to do that much faster without leaving the terminal.

• Implementing Co, a Small Interpreted Language With Coroutines #2: The Interpreter by Abhinav Sarkar

  The previous post was all about the syntax of Co. In this post we dive into the semantics of Co, and write an interpreter for its basic features.

• Learning Haskell by building a static blog generator by Gil Mizrahi

  In this book we will implement a simple static blog generator in Haskell, converting documents written in our own custom markup language to HTML.

Jobs

• Senior Haskell developer (ad)

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• Full stack functional developer (ad)

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• Haskell Developer at MLabs (ad)

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In brief

• Haskell in Plain English: a primer for the lexical semanticist by Michael Turner

  Haskell is what computer scientists call a pure, lazy, statically (strongly) typed, polymorphic functional language. Are you already slumping forward in defeat?

• Huge Project Build Systems by Neil Mitchell

  Shake won’t scale to millions of files, this post says what would be required to make it do so.

• Syd’s rules for sustainable Haskell by Tom Sydney Kerckhove

Show & tell

• explainable-predicates by Chris Smith

  The explainable-predicates package provides a Predicate a type, which is esssntially “a -> Bool that can explain itself.”

• GHCup version 0.1.17 by Julian Ospald

• merge, cropty, trust-chain by Samuel Schlesinger

  Figured I should post these new ones here, as they might actually be useful for someone else.

• random version 1.2.1 by Alexey Kuleshevich

  First release since the rewrite a year ago. This release mostly takes care of some technical debt, performance regression on ghc-9, support for ghc-9.2 and other minor fixups.

• Reactive Banana version 1.2.2.0 by Ollie Charles

  Reactive Banana is a library for functional reactive programming. This release is mostly a maintenance one, though there a few new goodies.

Call for participation

• dunai: Example in README uses old API
• explainable-predicates: Add an infix operator for accept