fetch_named_pos

Description:

public bool fetch_named_pos (string name, out int start_pos, out int end_pos)

Retrieves the position in bytes of the capturing parentheses named name.

If name is a valid sub pattern name but it didn't match anything (e.g. sub pattern `"X"`, matching `"b"` against `"(?P<X>a) ?b"`) then start_pos and end_pos are set to -1 and true is returned.

As end_pos is set to the byte after the final byte of the match (on success), the length of the match can be calculated as `end_pos - start_pos`.

Parameters:

this	MatchInfo structure
name	name of the subexpression
start_pos	pointer to location where to store the start position, or null
end_pos	pointer to location where to store the end position (the byte after the final byte of the match), or null

Returns:

true if the position was fetched, false otherwise. If the position cannot be fetched, start_pos and end_pos are left unchanged.