component GenericStack ( Stack, Element );
 type Stack;
      Stack (MaxSize = integer) -> Stack;
      Empty ( Stack )           -> boolean;
      Full ( Stack )            -> boolean;
      Push ( Stack, Element)    -> nothing;
      Pull ( Stack )            -> Element;
begin
      Stack(MaxSize) =
             Stack:[ MaxSize; index:=0; area=array (Element, MaxSize) ];
      Empty( stack ) = (stack.index <= 0);
      Full ( stack ) = (stack.index >= stack.MaxSize);
      Push ( stack, element ) =
                   [ exception (Full (stack), "Stack Overflow");
                     stack.index:=stack.index + 1;
                     stack.area[stack.index]:=element ];
      Pull ( stack ) =
                   [ exception (Empty (stack), "Stack Underflow");
                     stack.index:=stack.index - 1;
                     stack.area[stack.index + 1] ];
end component GenericStack;