Since the method in the Stack class are all offered by nature Array class in ruby standard lib, why would we need to implement a “Stack”? Maybe Array.new() is already a full-functioned stack =)

if you return self in “push” and “pop” like
def push(item)
@the_stack.push item
return self
end
you can do interesting things like

stack.push(3).push(5)

and test stack laws like

stack.push(3).pop() == stack

OK, for the latter equality you also need an equals-method for the stack class.
By the way, do you see a “correct” way to restrict stacks to certain data types, like e.g. in Java: Stack?

klaus

Thanks,

–James