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

• How and why I got started with Haskell by Shayne Czyzewski

  I decided I’d start learning it on the side and also look for a company that uses it as my next gig. That’s how my Haskell journey started, and how I got into Wasp a few months later.

• Memoization via Representables by Iago Leal de Freitas

  What is the most basic container type a language can have? Some people may answer vectors, others would go with hash tables, but in this post I am arguing in favor of functions.

• Named Routes in Okapi: Part III by Rashad Gover

  In the final post of this series, we’ll look at how to handle more complicated cases where we need to dispatch on other request information besides the path.

• The quantified constraint trick by Li-yao Xia

  My favorite Haskell trick is how to use quantified constraints with type families.

Jobs

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

In brief

• Everyday Applicatives! by Monday Morning Haskell

  I recently revised the Applicatives page on this site, and it got me wondering…when do I use applicatives in my code?

• Functional Futures: Dependent Types with David Christiansen by Jonn Mostovoy

  In this month’s episode of Functional Futures, our guest is David Christiansen, the Executive Director of the Haskell Foundation, a contributor to a number of dependently typed languages, and a dependent type advocate that has managed to introduce many people to the topic today through his work, talks, and texts.

• Hello World Haskell by Drew Olson

  No, there’s no need to worry about IO. In Haskell, when we want to perform an effect, we simply define a GADT to represent the capabilities of the effect.

• Leet Haskell-Style Lazy Evaluation In Python by X

  While lazy evaluation is very useful, the pervasive lazy evaluation in Haskell (rather than explicit lazy evaluation in other languages) probably causes more trouble than it’s worth.

Show & tell

• Automatic Differentiation in 38 lines of Haskell by Tammo Tesmer

  You can now differentiate (almost) any differentiable hyperbolic, polynomial, exponential, and/or trigonometric function.

• Stack version 2.9.1 by Mike Pilgrem

Call for participation

• cabal: cabal init fails when git not installed (regression in 3.8)
• hapistrano: Hapistrano can fail at rollback if ctoken points to a release that does not exists