Re: [Caml-list] Pattern matching and strings

[Sven Luther <luther@lambda.u-strasbg.fr>]

On Wed, Oct 02, 2002 at 04:12:34PM +0200, Alessandro Baretta wrote:
> I have to do a little bit of pattern matching on strings. My 
> first instict was to write something like the following.
> 
> let foo x = ...
> let bar x = ...
> ... = function
> | "foo" ^ rest -> foo rest
> | "bar" ^ rest -> bar rest
> | _ -> raise Unrecognized

What about :

... = function
  | str when String.sub str 0 3 = "foo" -> foo (String.sub str 2 (String.length str - 3))
  | str when String.sub str 0 3 = "bar" -> bar (String.sub str 2 (String.length str - 3))
  | _ -> raise Unrecognized

Sure, this code is not very optimal, i guess you could write a nicer
function which will test the string incrementally using just String.get
or something such, but i suppose it will do the thing you want.

Friendly,

Sven Luther
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