Issue 193 2020-01-09
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.
Five benefits to using
StandaloneKindSignaturesby Ryan Scott
GHC 8.10.1 is slated to be released soon, and among the improvements that it offers is the new
StandaloneKindSignatureslanguage extension. Standalone kind signatures (or “SAKS” for short) are like type signatures, except that they describe type-level declarations instead of term-level values.
Plucking Constraints by Matt Parsons
There’s a Haskell trick that I’ve observed in a few settings, and I’ve never seen a name put to it. I’d like to write a post about the technique and give it a name. It’s often useful to write in a type class constrained manner, but at some point you need to discharge (or satisfy?) those constraints. You can pluck a single constraint at a time.
Dhall - Year in review (2019-2020) by Gabriel Gonzalez
The Dhall configuration language is now three years old and this post reviews progress in 2019 and the future direction of the language in 2020.
I’ll first go over CPS basics, followed by discussing some use cases of CPS, and only in the end will I briefly touch upon the
Struggling to forget by Mark Karpov
In this post I show a use case and a way to implement conditional fixing of existentially quantified variables by universally quantified variables.
Formatting code in CodeWorld by Chris Smith
On Halloween, I switched CodeWorld’s Haskell formatter from hindent to Ormolu. I suppose I should say something about the reasons for the change.
18.S097: Programming with Categories by Brendan Fong, Bartosz Milewski, and David Spivak
In this course we explain how category theory has become useful for writing elegant and maintainable code. In particular, we’ll use examples from the Haskell programming language to motivate category-theoretic constructs, and then explain these constructs from a more abstract and inclusive viewpoint.
Organizing Our Package by Monday Morning Haskell
To start off the new year, we’re going to look at the process of creating and managing a new Haskell project. After learning the very basics of Haskell, this is one of the first problems you’ll face when starting out.
Semigroup resonance FizzBuzz by Mark Seemann
You can implement the FizzBuzz kata using the fundamental concepts catamorphism, semigroup and monoid. No if-then-else instructions or pattern matching is required. Instead, you use the string concatenation semigroup to enable resonance between two pulses, and the maybe catamorphism to combine with the list of numbers.
Tweeting a Blog Post via command line by Riccardo Odone
In the previous post we have seen how to scaffold a blog post with a Haskell script. Today, we are going to automate tweeting.
- Interos is Hiring Full Stack Haskell Software Engineers (ad)
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- BazQux Reader — your friend for reading feeds (ad)
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Optics By Example Cheat Sheets by Chris Penner
The following are appendices from Optics By Example, a comprehensive guide to optics from beginner to advanced!
Basic error reporting for optics by Yair Chuchem
Nothing, it is often desired to know why. Let’s define a
^??operator which returns an
Eitherinstead of a
Package of the week
This week’s package of the week is
cayley-client, a Haskell client for the Cayley graph database.