// the take
A draft book by Evan Czaplicki (Elm's creator) covering functional programming techniques — recursion, binary trees, graph traversal, tail-call elimination — built on top of what the official Elm guide already teaches. It's for developers who've finished the Elm guide and want a second pass on actually using FP idioms instead of just the language syntax.
Written by the person who designed the language, so the explanations of why certain patterns fit Elm (not just how to write them) are unusually well-grounded. The recursion section works through binary trees, merge sort, and tail-call elimination with actual diagrams (SVGs, GIFs) rather than just prose. Scoped narrowly to one audience (post-guide Elm learners) instead of trying to be a general FP reference, which keeps the content coherent.
It's an explicitly unfinished draft — the README says so outright — and the last commit was in 2022, so there's no indication it'll ever be completed. Coverage is thin: only two real chapters (recursion, graphs) exist, so anyone hoping for a full FP curriculum will hit a wall fast. The author has stated structural PRs won't be accepted (only typo fixes), so this is a frozen, non-collaborative artifact rather than a living resource — treat it as a read-once reference, not something to track for updates.
We read the README, the directory tree and a key source file in October 2026. Nobody pays to be listed. How we judge →