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

• Become a Better Haskeller by Learning About Inductive Types by Marko Dimjašević

  While we usually and easily see the benefits of having a static type system on simple types such as integers, we might fail to see the benefits of applying the same principles to user-defined data types.

• The Rubik’s Cube Group by Jared Corduan

  Permutations and symmetry are central themes of group theory, so it is perhaps not surprising that the Rubik’s Cube has a nice algebraic description.

• A Type of Programming by Renzo Carbonara

  Computers blindly follow orders, and at some fundamental level, programming is about giving computers orders to follow.

• Announcing Polysemy by Sandy Maguire

  I want to announce my new library polysemy — it’s higher-order, no-boilerplate, zero-cost free monads.

• Applicative Regular Expressions using the Free Alternative by Justin Le

  Today, we’re going to implement applicative regular expressions and parsers (in the style of the regex-applicative library) using free structures!

• Data Science in Haskell: An example using temperature data from Thailand and Myanmar by Dominic Steinitz

  I have just returned from a cycling trip from Bangkok to Yangon. It was pretty hot.

• Finding Property Tests by Hillel Wayne

  This was a pretty short dive into what makes a good property or contract. It also focused on just pure functions.

• GHC 8.8 Status by Ben Gamari

  Needless to say, bringing this migration to a close ultimately required that we compromise on the 8.8.1 release schedule.

• ghcid for Web App Development by Dennis Gosnell

  One of the downsides of developing web applications in Haskell is the long recompilation cycle.

Jobs

• Galois is Hiring! (ad)

  Galois is looking for Software Engineers/Researchers and Project Managers! We collaborate with organizations like NASA, DARPA, and Amazon Web Services to explore blue sky ideas and turn them into usable technology. Some of the things we’ve worked on in the past: Formal methods, static analysis, binary analysis, cryptographic algorithms, domain specific languages, programming languages theory, abstract interpretation, type theory, formal verification and software correctness, reinforcement learning, autonomous systems assurance, communication security, cyber-deception for network defense, DDoS defense, provable hardware security, statistical anomaly detection for detecting advanced persistent threats. We think working here is awesome (see https://lifeatgalois.com).

• Haskell programmers at Co-Star in New York

In brief

• A gentle introduction to symbolic execution
• A pure Test Spy
• Announcing DAML - a Haskell-based smart contract development language
• Announcing ghc-lib 0.20190404
• bitvec - memory-efficient bit vectors
• Call for Papers: Workshop on Functional High-Performance Computing 2019 at ICFP
• Code Review: Approve with Suggestions
• Deli: A performance modeling tool
• Generating More Difficult Mazes!
• GHC 8.6.5-rc1 released
• Hedgehog: Exercising your software in ways human testers would never imagine
• λauncher: GTK launcher application
• New release of FLTKHS with much better control over memory, tons of bug fixes and refactoring
• PureScript compiler release v0.12.4
• Summoner v1.3.0
• To Kata Haskellen Evangelion
• Web engines in Haskell

Package of the week

This week’s package of the week is gitlab-haskell, a library that queries and updates the database of a GitLab instance using the GitLab web API.

Call for participation

• hledger-flow: Change the version subcommand into a –version option
• unison: Make file watching robust to emacs .# files