Something that drives me up the wall is just how sloppy math notation can be. Supposedly this pure discipline, but many authors use custom conventions all over the place, shorthand, skip steps, etc.

Give me some math code, where the end result has to compile. No sneaky tricks allowed.

You want mathlib, the lean library of established results: https://github.com/leanprover-community/mathlib4

They skip steps in writing because they can generally do them and it obscures the flow of the argument to have every thing spelled out.

There is also a book on mechanics by the authors of SICP: https://mitpress.mit.edu/9780262028967/structure-and-interpr...

Lean doesn't have expressiveness notation. It's like Perl line noise.

> They skip steps in writing because they can generally do them and it obscures the flow of the argument to have every thing spelled out.

They do that in lean too; that's the idea of simp.