Re: "ocaml_beginners"::[] Get all w ords between two markers in a string

On 2016-07-15 10:57, [email protected] [ocaml_beginners] wrote:
> I need to get the list of all value names in a given module.
> So I put the contents of the mli in a string, and now I need
> to do some regexp manipulation on it, selecting all
> words between "val" and ":"  that's the part where
> I'm stuck.
>
> So what would be nice here is a grab_value_names:string->string
> function, such that
>
> grab_value_names "**** val get : ***** val set : **** val make : ***"
>
> returns ["get";"set";"make"].
>
>
> I'm not sure about how to do this with the Str module. I thought 
> first
> of cleaning everything between a ":" and "val" ; I tried the 
> following
> which doesn't work :
>
> let cleanup s=Str.global_replace (Str.regexp ":[.]+val") ":\nval" s;;

The best "hack" solution (that is w/o using a real parser of the real 
grammar), could be something like this:

1. Split the contents by whitespace

let words = Str.split (Str.regexp "[ \t]+") file_contents


2. Fold over this string list, searching for "val"/something/":" 
sequences

let check (had_val, had_str, names) str =
   match (str, had_val, had_str) with
   | (":", true, Some name) -> (false, None, name::names) (* saw a "val" 
and a name-string, now the ":"; add name to names, reset iterator *)
   | ("val", _, _) -> (true, None, names) (* just saw a "val" *)
   | (s, true, None) -> (true, Some s, names) (* saw a name-string after 
seeing a "val"; remember that string *)
   | _ -> (false, None, names) (* throw away everything else, reset the 
iterator *)

let _, _, names = List.fold_left check (false, None, []) words


The above code is not tested in any way.  ;)

regards
Markus

-- 
Markus Weißmann, M.Sc.
Technische Universität München
Institut für Informatik
Boltzmannstr. 3
D-85748 Garching
Germany
http://wwwknoll.in.tum.de/