miniblog.

TIL Rust has an ambiguity `if Foo {}` -- is `Foo` a value of type bool, or a struct? Rust solves this by defining a grammar production 'any expression except struct literals' and using it in this position. https://rust-lang.github.io/rfcs/0092-struct-grammar.html

There are *so many* ways that reading a text file can fail. Maybe it doesn't exist, it's a broken symlink, it's actually a directory, it's not the encoding you expected, or perhaps you just don't have the correct permissions. Reporting good errors is surprisingly labour intensive.

I regularly see the phrase "all Xs are Ys, but not all Ys are Xs" in teaching material. Even material for children! I have to re-read it every time. I very much prefer "Y is a more general category than X" or "X is a subset of Y". Do people find this phrasing helpful, or is it poor pedagogy?