Using a Stack with Ruby
by John Muchow
Although an array within Ruby supports all the operations you need for working with a stack (push, pop, etc), the problem is, Ruby does not offer a “formal” stack object and therefore the flexibility of the Ruby array can present problems. For instance, even if you intend to treat an array as a stack, nothing will stop you (or another developer using your code) from inserting or deleting anywhere within the stack.
We can work around this by creating a simple Stack class as follows:
class Stack def initialize @the_stack =  end def push(item) @the_stack.push item end def pop @the_stack.pop end def count @the_stack.length end end
Here is how you might use the stack:
stack = Stack.new stack.push('abc') stack.push(100) stack.count stack.pop()
If need be, you could also add a few convenience methods such as clearing the stack or looking at the last element (without popping it off the stack):
def clear @the_stack.clear end def look @the_stack.last end
Give this a try if you need to work with an array as a stack and want to play within the rules of how a stack is implemented as a traditional data structure.