NAME
	extract - extract a subpart of a string

SYNOPSIS
	string extract(string str, void|int start, void|int to)

DESCRIPTION
	Get a subpart of a string. Both 'start' and 'to' is a position in
	'str'. If the position(s) is negative then it is counted from the
	end of the string.
	If the 'start' is bigger than 'to' then an empty string is
	returned. An empty string is also returned if the subpart is
	outside the string in its entirety.
	Both positions is optional. If no position is given then 'str' is
	returned.
	If only 'start' is given then a string from 'start' to the end of
	'str' is returned.

SEE ALSO
	capitalize, lower_case, explode, implode