-- structural equality

type list {
  nil : list;
  cons : Any -> list -> list;
};

def writeLn := \x write x >> write "\n";

writeLn (1 = 1) >>
writeLn (0 = 1) >>
writeLn (nil = nil) >>
writeLn (cons 1 nil = nil) >>
writeLn (cons 1 nil = cons 2 nil) >>
writeLn (cons 1 nil = cons 1 nil) >>
writeLn (cons 1 nil = cons 1 (cons 2 nil)) >>
writeLn (cons 1 (cons 2 nil) = cons 1 (cons 2 nil))