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

• Cerveau: a future-proof web app for notes by Sridhar Ratnakumar

  Cerveau is a full-stack Haskell web app written using Reflex and Obelisk (GHCJS) in the frontend. This blog post describes the tech stack used.

• Four reasons that PureScript is your best choice to build a server in 2020 by Mike Solomon

  Here are four reasons that PureScript is the best way to build a server in 2020. I’ll tl;dr them here, but you should stick around for the bonus reason at the end as well!

• Be a goalkeeper by Dmitrii Kovanikov

  You may find this blog post useful, if you are interested in maintaining any project for a long time and keep your sanity during this process.

• The book “Functional Design and Architecture” is finished! by Alexander Granin

  The main idea of this book is to provide a comprehensive source of knowledge, a complete methodology of building real world applications in Haskell.

• Dependent types to code are what static types to data by Evgeny Poberezkin

  In the same way the static type systems ensure data validity by construction and prevent writing code that expects or creates invalid data, dependent types can ensure code validity on the code flow, logic and state transitions level.

• Ergonomic Haskell 1 - Records by Cody Goodman

  We have heard of Boring Haskell, Simple Haskell, and Fancy Haskell… but let’s ignore all of those and focus more on us. Why not make Haskell feel nicer to use?

• Let’s write a Haskell Language Server plugin by Pepe Iborra

  In this article we are going to cover the creation of an HLS plugin from scratch: a code lens to display explicit import lists.

• Traversals as Optimisations by Huw Campbell

  In this post, we’ll look at how we can apply high level optimisations in Core to significantly reduce our amount of code and remove redundant code branches.

• Virtual MuniHac 2020

  MuniHac is a Haskell hackathon in the tradition of other Haskell Hackathons such as the ZuriHac, HacBerlin, UHac and many others.

• Working with Hasura to improve GHC tooling by Well-Typed

  We’re glad to announce that we will be working with Hasura on improvements to GHC tooling over the coming months.

Jobs

Trying to hire a Haskell developer? You should advertise with us!

In brief

• Haskell - Enforcing Naming Convention with Parsec by Ken Aguilar

  I chose parser combinators because it’s my go-to method for parsing, and I personally think they’re convenient.

• Monoids (and semigroups) by Sam A. Horvath-Hunt

  Semigroups and monoids are mathematical structures that capture a very common programmatic operation, the reduction of multiple elements into one.

• The Simplest MonadFail Instance by Kazuki Okamoto

  It is not happy that Maybe discards the failure messages. So should we use Either? Either is not actually a MonadFail instance.

• Schuberts 9th Symphony (opening bars) sequenced by Haskell/TidalCycles code! by Oscar South

  This is a very literal example and only the absolute tip of the iceberg in terms of what fascinating ground can be covered with this approach to composing/performance.

• What killed Haskell, could kill Rust, too by Alexander Granin

  Haskell ruled in a whole bunch of interesting ways and yet it died. What killed it?

Show & tell

• cabal-auto-expose by Aditya Siram

  cabal-auto-expose is a build time library which, like hpack, auto detects new and removed Haskell modules and Backpack signatures in your project’s sources and exposes them for you so you don’t have to manually keep your .cabal file in sync.

• haskell-language-server version 0.4.0 by Alan Zimmerman

  0.4.0 introduces the import lens plugin, which can convert your import statements into qualified imports, or into an explicit import list.

• kmonad version 0.4.0 by David Janssen

  Welcome to KMonad, The Onion of Keyboard Management. Now on Windows, Linux and Mac!

• SBV version 8.8 by Levent Erkök

  SMT Based Verification in Haskell

Call for participation

• LambdaHack: Render the message log so that a full window of messages is visible when looking at the newest message
• ghcide: Encourage space-leak correct value storage