Haskell Weekly


Issue 126 2018-09-27

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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.


  • GHC 8.6.1 released

    The GHC team is pleased to announce the availability of GHC 8.6.1, the fourth major release in the GHC 8 series. The 8.6 release fixes over 400 bugs from the 8.4 series and introduces a number of exciting features.

  • co-log: Composable contravariant combinatorial comonadic configurable convenient logging

    I’m going to describe in details and with examples how one can build a flexible, extensible and configurable logging framework using different parts of Haskell — from monad transformers and contravariant functors to comonads and type-level programming with dependent types.

  • Freer than free

    freer-simple is a fantastic library and I will definitely use it again. I found some gaps in the documentation that I aim to address here.

  • Let’s Go Mainstream with Eta!

    My name is Rahul Muttineni, CTO of TypeLead, working on building services around a language named Eta. I’ll give an overview of how the project started, and where it is now.

  • Rechunking lazy bytestrings

    Given that SIMD registers are currently up to 512-bits in size, the chunk size will need to be multiples of 64-bytes to work with arbitrary SIMD instructions. This post will look at the chunk size Haskell’s bytestring library actually gives us and explore some ways we can get the required chunk size we need.

  • The type Tetris toolbox

    The type Tetris toolbox is a set of features and language extensions which allow subdividing expressions that I was having trouble getting to type check. It enables “debugging at the type level”.

  • Well-typed paths: revisited

    Using temporary files, reading directory contents, writing logs — in all of these cases you need to clarify the path. But path can be specified either in absolute or relative form. And it can point either to a directory or a file.

  • What the heck is Typeable!?

    I used to find the Typeable type class in Haskell particularly confusing and even more, pointless. Pointless because, we are talking about a statically typed language where all the types are known at compile time.


  • Haskell developer at Relex in Helsinki

    We are looking for Haskell developers to join our internal tool development team. Relex produces a high performance supply chain management solution with a custom in-memory database.

In brief

Package of the week

This week’s package of the week is binary, a library for binary (de)serialization of Haskell values using lazy ByteStrings.

Call for participation