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.

Coming from JS or Python, imports in Rust feel weird. They're entirely optional aliases for fully qualified symbols, which are always available. I don't know of many other languages where you can just start using libraries. Java is the only one I can think of.

Assertions are a surprisingly nuanced design space. In a test, if I assert `x < y`, I really want to see the values of x and y when it fails. Do you define an API for every possible predicate (Python's assertLess, expect.js) or try to support the native syntax (c.f. pytest)?