!macro a @r {
		!if @r != 1 {
			!error "assertion failed"
		}
	}

	squares = [1, 4, 9]
	emptylist = []
	primes = [2, 3, 5, 7]
	+a primes + emptylist + squares == [2,3,5,7,1,4,9]

	somestring = "Arthur"
	emptystring = ""
	otherstring = "Ford"
	+a otherstring + emptystring + somestring == "FordArthur"

	collection = []
	!for c in "Trillian" {
		!set collection = collection + [c]
	}
	+a collection == [84, 114, 105, 108, 108, 105, 97, 110]