Re: [Ocaml-lib-devel] Filename and file manipulation

[<syl...@po...>]

Hello,

On Sun, Feb 01, 2004 at 11:22:14AM +0100, Nicolas Cannasse wrote:
> Just a little additionnal suggestion about SysUtil :
> 
> SysUtil is heavily relying on the Unix module for its implementation, and
> that's ok. But only one feature ( the Match pattern to match the filename
> using a regexp) is using the Str module. In order to reduce dependencies, I
> think you should abstract the Match, using an user define regexp matching.
> For exemple :
> 
> in SysUtil.mli :
> ---
> 
> val configure_regexp : make:(string -> 'a) -> test:('a -> bool) -> unit
> 
> in SysUtil.ml :
> -----
> let regexp_make= ref (fun _ -> failwith "Regexp is not configured")
> let regexp_test = ref (fun x _ -> failwith "Regexp is not configured"; x =
> 0) (* we need to give a type here for ungeneralized variables *)
> 
> let configure_regexp ~make ~test =
>     regexp_make := Obj.magic make; (* we need to cast here because the type
> we need is slighty different *)
>     regexp_test := Obj.magic test
> 
> * and in testing Match :
>     let reg = !regexp_make str in
>     fun x -> !regexp_test reg x
> 
> Then the user could write :
> 
> SysUtil.configure_regexp Str.regexp Str.string_match
> before making any Match
> 
> ( we can also use only one function with currying trick :
>     SysUtil.configure_regexp (fun reg -> let reg = Str.regexp reg in
> (Str.String.match reg))
> but it's then less comprehensible for the user )
> 
> Regards,
> Nicolas Cannasse
> 
> 
> 

Ok, you are perfectly right. I will remove the Str test and replace it
by a user provided test... But i won't use obj.magic to cast regexp... I
prefer let the user do some more work to have something fully ocaml
compliant than using a clever trick that is not documented ( personnal
point of view on obj.magic ). 

Thank you for your remark.
Kind regard
Sylvain LE GALL