$date = "10-09-2004";

print &replace($date, q"(\d+)-(\d+)-(\d+)", q"$3-$2-$1"), "\n";

sub replace {

	my $value				= shift;
	my $this				= shift;
	my $with				= shift;
	my $modifiers			= shift;

	$this = &pattern($this, $modifiers);

	if ($modifiers =~ /g/) {
		$value =~ s/$this/qq{qq{$with}}/gee;
	} else {
		$value =~ s/$this/qq{qq{$with}}/ee;
	}

	return $value;

}

sub pattern {

	my $pattern				= shift;
	my $modifiers			= shift;

	if ($modifiers =~ /[^gism]/) {
		die "Only m, i, s and g are valid pattern modifiers.";
	}

	$modifiers =~ s/g//;

	return qr"(?$modifiers)$pattern";

}