miniblog.

I'm having fun writing a simple type checker, but I'm learning firsthand why syntax-directed checking doesn't work. It prevents inference. My checker catches real bugs, but it can't handle cases like this: [1, 2].map(fun(x) { x + 1; }) I think I need bidirectional checking.

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

Really cute approach to reporting type errors: when there's a type error, show an example of a runtime error that the type check has prevented! Data-Driven Techniques for Type Error Diagnosis https://escholarship.org/uc/item/59s4h4pv