miniblog.

What types should you infer when code is invalid? In Garden, + only applies to integers. What should the type of "x" + "y" be? (1) Int: This produces cascading errors. (2) String: We've already emitted an error anyway. (3) Bottom. Opinions?

Counter-intuitively, if you're writing a parser for a programming language, you need it to be a total function. As soon as you build IDE tooling, you need ASTs from invalid or incomplete input. The parser should return (Ast, List<Error>) rather than Result<Ast, Error>.

I'm impressed by how many options I'm offered in Common Lisp (in this case sbcl on Sly) for a simple error like an invalid variable name!