OSlash (Ø) is a library for learning and understanding functional programming in Python 3.12+. It re-implements concepts from Learn You a Haskell for Great Good! using Python with modern type ...

Note July 6th 2025: this post’s original title was “A list is a monad”. It has been changed to “List is a monad”. Note Sept 13 2025: this post has been revised based on the feedback from the Hacker ...

In functional programming, the Either monad serves a special purpose: it encapsulates a value that can be one of two types, traditionally called Left and Right. The ...

Rie Takumi is a freelance list writer. Aside from budgeting for gacha and vtuber superchats, they watch hockey and crochet to relax, which is ironic but that's how it goes. Perhaps the first thing ...