Escape sequences in Ocaml

Question

Is there a standard way in Ocaml, to convert from (for example) a\n (a three byte string: 0x61,0x5c,0x6e) to a two byte string: 0x61,0x0a ?

My Ocaml program can receive strings with escaped characters, how to "unescape" them?

Answer 1

Nice solution from http://caml.inria.fr/mantis/view.php?id=3888:

let unescape s = Scanf.sscanf ("\"" ^ s ^ "\"") "%S%!" (fun u -> u)

Answer 2

If you are using OCaml 4.0.0 or later, you can use Scanf.unescaped.

Example:

# open Scanf
# Scanf.unescaped "a\\n";;
- : bytes = "a\n"      
# Scanf.unescaped "\\n\\t\\\\";;
- : bytes = "\n\t\\"

Interface: (via OCaml docs)

val unescaped : string -> string

Return a copy of the argument with escape sequences, following the lexical conventions of OCaml, replaced by their corresponding special characters. If there is no escape sequence in the argument, still return a copy, contrary to String.escaped.

Since 4.00.0