% Simple list reversal in ABSYS
% Pattern matching and list processing example

REVERSE([]) = [];
REVERSE([H|T]) = APPEND(REVERSE(T), [H]);

APPEND([], L) = L;
APPEND([H|T], L) = [H|APPEND(T, L)];

% Test cases
TEST1 = REVERSE([1, 2, 3, 4, 5]);
TEST2 = REVERSE([A, B, C]);