README.md

Quchen's articles

This repository is filled with articles I have written and needed online for various reasons. Below is a short summary of the articles available publically; the repository may contain files not mentioned below, in which case they're probably unfinished or otherwise not worth reading at this point.

Haskell related

General, tutorials

• Algebraic blindness is about how algebraic data types sometimes make Boolean Blindness even more complex.
• The build function explained, which is an important piece in a popular optimization technique
• The Cont monad explained
• Some lazy IO pitfalls
• The fix function, one possible fundamental building block of recursion
• Frequently Brought Up Topics in Freenode's #haskell channel
• Basic Haskell functions written in easily comprehensible notation. Nice for explaining e.g. sequence.
• What I thought was cool about Haskell some time ago. I should update this one day.
• Equality table of Haskell values. (live version) Created in a time where it seemed to be en vogue to create tables for the == operator in various languages. Spoiler, it's terribly boring, because it should be.
• How to fix, or avoid fixing, certain warnings
• My Haskell code style and the rationale behind it
• Informal description of class instances gives non-technical descriptions of various common class instances.
• An extensive tutorial on the Hindley-Damas-Milner type inference algorithm
• Lens infix operators cheat sheet provides an overview of what the individual symbols in infix operators of the lens library stand for.
• Löb/Möb is about an interesting, simple, complicated and quirky recursive function.
• Reader instance derived shows how to write the usual Reader monad instance starting from something readable and comprehensible.
• The second Functor law is redundant
• Tag, don't type is about avoiding type synonyms, and using Data.Tagged instead.
• How to write unmaintainable Haskell, inspired by How to write unmaintainable code
• Useful techniques I've found over the years and haven't seen described elsewhere
• Write yourself a Brainfuck in an hour implements a very simple Brainfuck interpreter in Haskell, with plenty of room to go on afterwards.
• Make macros mean something – readable backwards compatibility with CPP talks about how to define readable macro synonyms for writing backwards compatible libraries.

Proposals

• Applicative-Monad proposal (AMP) is the original text of the 2013 Applicative-Monad proposal, which was the starting point for Applicative becoming a superclass of Monad in GHC 7.10.

• Rules for typeclass laws wasn't proosed yet

• The MonadFail proposal is a proposal similar to the AMP, with the goal of removing fail from the Monad typeclass.

  • Original text
  • Update after one week of discussion.