// Substitution when subexpression isn't found
	{"(x)?", "$1", "123", "123"},
	{"abc", "$1", "123", "123"},

	// Substitutions involving a (x){0}
	{"(a)(b){0}(c)", ".$1|$3.", "xacxacx", "x.a|c.x.a|c.x"},
	{"(a)(((b))){0}c", ".$1.", "xacxacx", "x.a.x.a.x"},
	{"((a(b){0}){3}){5}(h)", "y caramb$2", "say aaaaaaaaaaaaaaaah", "say ay caramba"},
	{"((a(b){0}){3}){5}h", "y caramb$2", "say aaaaaaaaaaaaaaaah", "say ay caramba"},
}