Format strings in OCaml

OCAML doesn't have string interpolation, but it does have C-style format strings (but type-safe). Here's an example:

let hello name = Printf.printf "Hello, %s!\n" name
(* Can be written as: let hello = Printf.printf "Hello, %s!" *)

This is type-safe in an almost magical way (example REPL session):

# hello 1;;
Error: This expression has type int but an expression was expected of type
         string

It can however be a little tricky to wrap your head around:

# let bob …

error example format hello ocaml session string strings style type