# gosub(regexp, replacement [, target])
# Aka global original sub
# Behaves like gsub, however doesn't try regexp on previoud replacements
# and returns the result string, rather than doing it inplace.
function gosub(regexp, replacement, target) {
	if (!length(target)) {
		target = $0;
	}

	result = "";
	matched = "";
	while (match(target, regexp)) {
		result = result substr(target, 1, RSTART - 1);
		matched = substr(target, RSTART, RLENGTH);
		target = substr(target, RSTART + RLENGTH);

		sub(regexp, replacement, matched);
		result = result matched;
	}

	return result target;
}

# gesub(regexp, exregexp, replacement [, target])
# Aka global excluding sub
# Behaves like gsub, however substitutes only where exregexp doesn't match
# and returns the result string, rather than doing it inplace.
function gesub(regexp, exregexp, replacement, target) {
	if (!length(target)) {
		target = $0;
	}

	result = "";
	while (match(target, exregexp)) {
		beg = substr(target, 1, RSTART - 1);
		exclude = substr(target, RSTART, RLENGTH);
		target = substr(target, RSTART + RLENGTH);
		gsub(regexp, replacement, beg);
		result = result beg exclude;
	}

	gsub(regexp, replacement, target);

	return result target;
}