Re: [Caml-list] String.(r)index_from

[Francois Berenger <berenger@riken.jp>]

Hi Florent,

If you find yourself doing non trivial things with
the String module, maybe it means you should use another
module which works at a higher level.
Str for example, or some other module from extended
versions of the stdlib.

Regards,
F.

On 8/21/13 12:53 AM, Florent Monnier wrote:
> 2013/08/12, Gerd Stolpmann wrote:
>> IMHO, this is the right behavior. When walking over strings, it is often
>> practical to consider the position after the last character as legal
>> position. So far I see, this is consistent in the String module, e.g.
>> you can also do String.sub "abc" 3 0.
>>
>> It's a bit like considering 0 as natural number.
>
> Hi Gerd,
>
> Well I can understand that there is some kind of logic there, even if
> the logic is different than the one that I expected at the beginning.
> But it doesn't seem to be very consistent with the functions that
> perform searches from right to left:
>
> # let s = "012";;
> val s : string = "012"
>
> # let n = String.length s ;;
> val n : int = 3
>
> # String.sub s n 0 ;;
> - : string = ""
>
> (* OK, so why is n valid for String.sub, but not for these below? *)
>
> # String.rcontains_from s (n-1) '2' ;;
> - : bool = true
>
> # String.rcontains_from s n '2' ;;
> Exception: Invalid_argument "String.rcontains_from".
>
> # String.rindex_from s (n-1) '2' ;;
> - : int = 2
>
> # String.rindex_from s n '2' ;;
> Exception: Invalid_argument "String.rindex_from".
>
>