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

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

2013/08/19, Damien Doligez wrote:
> Hi,
Hi,

> Indeed, it was carefully designed this way. When you're doing
> index_from s 3 '3', you're looking for the character 3 in the empty
> string.

OK, I do understand now that the offsets don't really point to cells
but on the interval (or separations) between cells. So 0 points to the
left part of the first char, and the offset = length points to the
right part of the last char, but I still don't catch the logic for the
functions that operates from right to left:

# let s = "012";;
val s : string = "012"

# String.rindex_from s 0 '0' ;;
- : int = 0

# String.rindex_from s (-1) '0' ;;
Exception: Not_found.

# String.rcontains_from s 0 '0' ;;
- : bool = true

# String.rcontains_from s (-1) '0' ;;
Exception: Invalid_argument "String.rcontains_from".

For the functions that operates from left to right, the ranges are
then consistently always the same, but not for the functions that
operates from right to left.

-- 
Regards