Re: [Ocaml-lib-devel] Re: [Caml-list] String to list to string

[Richard J. <ri...@an...>]

On Tue, Feb 15, 2005 at 08:34:03AM -0500, Eric C. Cooper wrote:
> On Tue, Feb 15, 2005 at 10:33:16AM +0000, Richard Jones wrote:
> > If you can suggest suitable fold_left and fold_right functions, then
> > they can be added to ExtLib.
> 
> Here's what I use:
> 
> val string_fold_left : ('a -> char -> 'a) -> 'a -> string -> 'a
> val string_fold_right : (char -> 'a -> 'a) -> 'a -> string -> 'a
> 
> let string_fold_left f init str =
>   let n = String.length str in
>   let rec loop i result =
>     if i = n then result
>     else loop (i + 1) (f result str.[i])
>   in
>   loop 0 init
> 
> let string_fold_right f init str =
>   let n = String.length str in
>   let rec loop i result =
>     if i = 0 then result
>     else
>       let i' = i - 1 in
>       loop i' (f str.[i'] result)
>   in
>   loop n init

No one had any objections, so I added these and implode/explode to
ExtString.

Rich.

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Richard Jones, CTO Merjis Ltd.
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