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

[Florent Monnier <monnier.florent@gmail.com>]

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".


-- 
Regards