#include SEQ.cam

; Creation date: Fri Dec 12 10:56:58 WET 1997

STATE st   : A-seq;

FUNC ENQ(a: A): VOID
STATE  st    <- st    ^ <a>;

FUNC FRONT(): A
PRE st   !=<>
RETURN hd(st   );

FUNC DEQ(): A
PRE st   !=<>
STATE  st    <- tl(st   );