Issue 159 2019-05-16

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

Functor-Of by Vladimir Ciobanu

Due to kind restrictions, the Haskell Functor cannot represent a lot of valid functors: functors of higher kinded types (higher than * -> *), contravariant functors, invariant functors, etc.
A Basis For Sequential Execution: Monads, Arrows, and More by Tyler

On the first day, there was light. On the second day, there was silicon. And on the third day, there was assembly.
Functional architecture is Ports and Adapters by Mark Seemann

Functional architecture tends to fall into a pit of success that looks a lot like Ports and Adapters.
Handling GHC parser errors right by Shayne Fletcher

Did you know, a POk parse result from the GHC parser doesn’t necessarily mean the parse was OK? This blog explains what’s up with that.
Haskell Showroom: Switching between different AWS accounts by Deni Bertović

Continuing this series, in this post I will talk about how to effectively switch between different AWS accounts.
How I wrote a proof of concept in five hours and launched a first version in a week by Tom Sydney Kerckhove

I had an idea, made a proof of concept, and then built it out over a week. This is the story of how that happened.
Implicit Corecursive Queues by Donnacha Oisín Kidney

I was looking again at one of my implementations of breadth-first traversals and I was wondering if I could fuse away the intermediate list.
Integrated versus Manual Shrinking by Edsko de Vries

Even with integrated shrinking, you still have to think about shrinking. There is no free lunch. Also, important new Hedgehog release!
Lightweight, efficiently sampleable enumerations in Haskell by Brent Yorgey

For another project I’m working on, I needed a way to enumerate and randomly sample values from various potentially infinite collections.
Shake with Applicative Parallelism by Neil Mitchell

Shake now does that Applicative trick from Haxl.

Jobs

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Including but not limited to: Software Engineers/Researchers, Project Managers, Hardware Engineers, Red Team Lead, Software Integration Engineer.

We collaborate with organizations like NASA, DARPA, and AWS 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, cryptographic algorithms, abstract interpretation, type theory, formal verification, reinforcement learning, autonomous systems assurance, communication security, cyber-deception for network defense, DDoS defense, provable hardware security, and statistical anomaly detection for detecting advanced persistent threats. We think working here is awesome; see lifeatgalois.com.
Engineers at Soostone in New York City
Haskell Developer at Select * in Stockholm

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

In brief

Package of the week

This week’s package of the week is dhall-to-cabal, a tool that generates Cabal files from Dhall expressions.

Call for participation

Events

North America

2019-05-16 in Raleigh, NC, USA by Raleigh Haskell Meetup: (hack . yack)
2019-05-16 in Las Vegas, NV, USA by Las Vegas Functional Programming User Group: Functional Programming Meetup
2019-05-16 in Boston, USA by Categorical Databases: Ryan Open Office Hours
2019-05-16 in Toronto, ON, Canada by Toronto Haskell Meetup: Haskell Meetup: From Beginner to Less Beginner
2019-05-18 in San Diego, CA, USA by San Diego Software Development Deep Dive: Diving deeper into software development discussions
2019-05-18 in Berkeley, CA by Code Self Study: Open Programming Session (Saturday Afternoon)
2019-05-18 in Harwich, USA by Cape Cod Functional Programming Meetup: Redux & Algebraic Data Types (ADTs)
2019-05-18 in Boston, MA, USA by Weekly Functional Programming Meetup: Hang out + short talk (Data types à la Carte by Jinxuan Zhu)
2019-05-18 in Bellevue, WA, USA by Seattle Area Haskell Users’ Group: General discussion
2019-05-19 in Des Moines, IA, USA by Des Moines Haskell Study Group: Week 1. Introduction. Lambda calculus. (Chapter 1)
2019-05-20 in Lehi, UT, USA by Utah Haskell: Utah Haskell Meetup | Book Club
2019-05-20 in Irvine, CA by Orange Combinator - Functional Programming In OC: Combinating - The Weekly Function
2019-05-21 in Brooklyn, NY, USA by New York Haskell Users Group: Parallel and Concurrent Haskell Reading Group
2019-05-21 in Minneapolis, USA by HaskellMN: HaskellMN Monthly Meetup
2019-05-21 in Carmel, USA by Indy FP: Einstein, Hats, and Propaganda: An Introduction to Distributed Systems
2019-05-22 in New York, NY, USA by New York Haskell Users Group: The Good, the Bad, and the Ugly: Haskell in Enterprise

Europe

2019-05-16 in Frankfurt, Germany by Frankfurt Haskell User Group: RIO eine neue Standard Library für industrielle Haskell Anwendungen
2019-05-16 in London EC2, United Kingdom by Skills Matter - X Matters Keynote Series - Developer Events: Keynote by George Adams on AdoptOpenJDK - And how it impacts you in 2019
2019-05-20 in Karlsruhe, Germany by Karlsruhe Haskell Meetup: Haskell Monday
2019-05-20 in London, United Kingdom by Skills Matter - X Matters Keynote Series - Developer Events: Skills Matter Open House May
2019-05-20 in London EC2, United Kingdom by Skills Matter - X Matters Keynote Series - Developer Events: Keynote by Noel Welsh on the Elements of Tagless Final Style
2019-05-20 in Zürich, Switzerland by HaskellerZ: Jonas Wälter - Functional Programming for Web and Mobile
2019-05-21 in Berlin, Germany by Berlin Haskell Users Group: Up to Your Elbows in GHC
2019-05-21 in Katowice, Poland by Functional Miners: Spotkanie 05.2019 (Functional Programming for Humans)
2019-05-21 in Lille, France by Lille FP: LilleFP15 : FP pure & applications multiplateformes avec Reason-React-Native
2019-05-21 in London EC2, United Kingdom by Skills Matter - X Matters Keynote Series - Developer Events: Keynote by Antony Marcano on 5 Mistakes Made in Agile Transformations

Oceania

2019-05-20 in Perth, Australia by Perth Functional Programmers: Cryptography in Haskell
2019-05-21 in Christchurch, New Zealand by Functional Christchurch: Functional Programming
2019-05-22 in Canberra, Australia by CanFP - The Canberra Functional Programming Group: CanFP Monthly meetup

South America

2019-05-16 in AAQ, Argentina by Buenos Aires Haskell Meetup: BAHM - Mayo 2019

Africa

2019-05-18 in Nairobi, Kenya by Nairobi JVM: CI/CD and Evolving a Stack from a Small Tight-knit Engineering Team