Issue 325 2022-07-21
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.
Configuration of a Polysemy application by Thomas Mahler
One question that came up: why did I explicitly load configuration before starting the Polysemy effect interpreter? Wouldn’t it be much more in line with the overall idea of my Polysemy Clean Architecture to handle this loading also as an effect?
The Lazy Way to Solve Differential Equations by Iago Leal de Freitas
By the end of this post we gonna be able to solve this differential equation simply by writing the equivalent Haskell definition
Just as Haskell has a type system to classify values, it has a kind system to classify types. It provides a way to reason about what types make sense to construct.
Parallelising Source Positions by Benjamin Hodgson
My parsing library Pidgin has some infrastructure to track positions in a textual input file, for the purposes of error reporting.
Universal and Existential Quantification in Haskell by Stepan Prudnikov
In logic, there are two common quantifiers: the universal quantifier and the existential quantifier. You might recognize them as ∀ (for all) and ∃ (there exists).
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Data Structures: Hash Maps! by Monday Morning Haskell
Today we’re taking the next logical step in the progression and looking at Hash Maps. Starting later this week, we’ll start looking as lesser-known Haskell structures that don’t fit some of the common patterns we’ve been seeing so far!
Episode 15 by Facundo Dominguez
Facundo Dominguez is interviewed by Niki Vazou and Joachim Breitner. Facundo Dominguez tells us the difference between STM and SMT.
Haskell Foundation board minutes, July 14, 2022 by Théophile Choutri
You can check out the minutes and agenda for the Board meeting that took place on the 2022-07-14.
Haskell Foundation DevOps Weekly Log, 2022-07-15 by Bryan Richter
This week I moved into phase 2 of CI failure reporting. Following on last week’s CI failure dashboard, I’m now working on a system to backfill new errors as they are categorized.
Show & tell
effectful: an easy to use, performant extensible effects library by Andrzej Rybczak
Hey everyone, It’s taken ages, but finally the initial release of the effectful library is here.
filepath-18.104.22.168 released by Julian Ospald
This release implements support for the “abstract filepath proposal” (AFPP). There are no breaking changes in the existing API.
ghc-plugin-non-empty by Dmitrii Kovanikov
GHC Compiler Plugin for automatically converting list literals to the
NonEmptytype from the
servant-oauth2: first release by Noon van der Silk
It’s a light-weight wrapper around wai-middleware-auth, but done within the context of “modern servant”, so you can lift authentication/authorisation information to the type level.
stargaze-cli by Qiao Wang
Stargaze is a CLI tool to help you manage your starred projects on GitHub.