module Ordered_collection_common:sig..end
normalize length_fun thing_with_length i is just i, unless
i is negative, in which case it's length_fun thing_with_length + i.
This is used by various python-style slice functions.val normalize : length_fun:('a -> int) -> 'a -> int -> intval slice : length_fun:('a -> int) ->
sub_fun:('a -> pos:int -> len:int -> 'a) -> 'a -> int -> int -> 'aval get_pos_len_exn : ?pos:int -> ?len:int -> length:int -> int * intget_pos_len and get_pos_len_exn are intended to be used by functions
that take a sequence (array, string, bigstring, ...) and an optional pos
and len specifying a subrange of the sequence. Such functions should call
get_pos_len with the length of the sequence and the optional pos and
len, and it will return the pos and len specifying the range, where
the default pos is zero and the default len is to go to the end of the
sequence.
It should be the case that:
0 <= pos <= length len >= 0 pos + len <= length
Note that this allows pos = length and len = 0, i.e. an empty subrange
at the end of the sequence.
get_pos_len returns (pos', len') specifying a subrange where:
pos' = match pos with None -> 0 | Some i -> i
len' = match len with None -> length - pos | Some i -> i
val get_pos_len : ?pos:int -> ?len:int -> length:int -> (int * int, string) Result.t