miniblog.

Type signatures are optional in Haskell, but in OCaml you can even specify partial signatures (e.g. just one parameter). Maybe return types are more valuable to annotate? I can often guess params based on the name, but I have to read the function body for the result.

I like Common Lisp's ability to annotate functions with types *for performance*. It removes much of the dynamic typing overhead.

Emacs tip of the day: annotate your functions! The byte compiler can replace entire function calls at compile time if your function is pure.