# Haskell

- tags :: {Programming Languages}

Haskell is the epitome of many of the successes of strong type systems and some of the worst programming language decisions made.

This is an [incredible breakdown of how GHC works]. Absolutely worth learning if you want to learn more about the language, but I'm not sure to what degree it's worth spending time on now.

[GitHub - thma/WhyHaskellMatters: In this article I try to explain why Haskell...] is an overview of the language and why it matters.

## Utilities

### Hoogle

Search for programs using their type. This is the aspect of Haskell that's most appealing: with more information encoded into the type system - safety guarantees aside - we get far, far better program search and reuse - because our types generally express the functionality of the program! Being able to reuse code is incredibly nice for lots of reasons.

[https://aaronguo1996.github.io/project/hoogleplus/]hoogle plus :: search for *combinations* of functions with hoogle! This is also at [https://hoogleplus.goto.ucsd.edu/.]

## Simple Haskell

is a movement to program in only a simple, disciplined subset of the language, in order to build a robust foundation of beginner-friendly code that's easy to onboard programmers to without digging into the weeds of scary monads and typeclasses. Simple Haskell preludes exist to replace the default prelude, and the discipline usually recommends a set of language extensions to get everyone started.

[Write Junior Code]: A plea for Haskell developers to actually write code that people can understand and hire for. [Boring Haskell Manifesto] also describes this, as does [Simple Haskell]. It's very possible that more time has been spent pontificating about Haskell than actually writing production code in the service... [My thoughts on Haskell in 2020 - Marco Sampellegrini].

[Haskell mini-patterns handbook :: Kowainik]: A book of Haskell design patterns. (I recall reading this on a particular lunch break out of the Skira office; the ideas sunk in at the time and could be applied to our class PL code. We should have used it).

There are many resources written with this practice in mind.

- [Real World Haskell]
- [The golden rule of software quality : haskell]
- [GitHub - graninas/software-design-in-haskell: Software Design in Haskell. A s...]
- [Appendix to Software Design in Haskell · GitHub]
- [Type Classes] : start learning haskell with good documentation, various inline demonstrations, and a book.
- [haskell competency matrix]: to identify where you're at with respect to your Haskell knowledge and figure out what you have left to learn.
- [adventures in uncertainty: Towards Faster Iteration in Industrial Haskell]

## GHC

[How Accursed and Unutterable is accursedUnutterablePerformIO?]

[Runtime Support for Multicore Haskell: a Retrospective | SIGPLAN Blog] : On multicore Haskell. One of the biggest benefits of pure functional programming is parallel computation, so this better work well.

[Type Technology Tree : ezyang’s blog]: How to consider different Haskell language extensions. What do they mean? How can they be applied? How do we determine when to use them?

[GHC.Generics]: Datatype-generic functions that programmers can use and reuse, parameterizing them.

### TemplateHaskell

- backlinks :: {Macros}

[An excellent Template Haskell Tutorial], and another: [https://github.com/leonidas/codeblog/blob/master/2011/2011-12-27-template-haskell.md]

## Interesting

[GitHub - tathougies/hos: The functional Haskell kernel]: a kernel for a Haskell operating system. (What?)

[Paweł Szulc - Maintainable Software Architecture in Haskell (with Polysemy) -...]

[Hasktorch: A Comprehensive Haskell Library for Differentiable Functional Prog...]

[Implementing Linear Haskell - YouTube]

[Lambda calculus on the type level with GHC 7.11.20151212. · GitHub]

## Categories

[Comonads | Bartosz Milewski's Programming Cafe]

[https://ncatlab.org/nlab/show/comonad#definition]{Math}

[Haskell and Category Theory] {Category theory}

[Category Theory | Haskell Language Tutorial]

[http://www.haskellforall.com/2013/02/you-could-have-invented-comonads.html]

## Getting Started

### Setting Up Stack

```
wget https://get.haskellstack.org/stable/linux-x86_64-static.tar.gz
rm -rf linux-x86_64-static.tar.gz
export PATH=$PATH:./s
```

#### Creating a project

creating project:

```
stack new Other simple
stack setup
getting ncurses5-compat-libs:
```

## Proofs in Haskell?

- [A casual guide to proving things in Haskell]
- [Dependent types in the context of Haskell (limited support)]
- [https://ucsd-progsys.github.io/liquidhaskell-blog/2020/04/12/polymorphic-perplexion.lhs/:] Expression of orderings with haskell dependent types, via liquidhaskell.
- [A more rigorous overview of dependently typed programming in Haskell]
- [Towards Tactic Metaprogramming in Haskell :: Reasonably Polymorphic]

## things to remake in haskell (and maybe racket!)

[https://m.youtube.com/watch?v=FYTZkE5BZ-0]:: make {music} with haskell from scratch

## etc

[GitHub - davdar/parsing-with-derivatives-haskell: The original parsing with d...] : Parsing with derivatives, as the parser maps to one! Very cool idea.

[Haskell for all: Introductions to advanced Haskell topics]

[djinn: Generate Haskell code from a type]! With an associated blog post: [Let’s play a game : ezyang’s blog].

[Conal Elliott » Blog Archive » “Everything is a function” in Haskell?]

[linear] algebra library implemented and experimented with in Haskell.

[accelerate: An embedded language for accelerated array processing]: