title: Procedure Recursion and Stacking
body: <p>To model the run-time semantics of procedures, it is known that a stack is generally needed. 
  1. If the language does not allow procedure recursion, do we have to have stacks? 
  2. If the language does allow procedure recursion, but a recursive call can only happen at the end of a procedure, do we have to have stacks?</p>