Universal virtual PDA. A pushdown automaton adds a stack to a DFA and the ability to, on a...

Universal virtual PDA. A pushdown automaton adds a stack to a DFA and the ability to, on any transition, push and pop symbols from the stack. Specifically, each transition has an additional label x/y that says to pop the stack and push y if the symbol returned was x, with /y meaning just push y without popping anything, x/ meaning pop without pushing if the symbol returned was x, and / meaning just pop the stack. Develop a program analogous to PROGRAM 5.1.3 that can simulate the operation of any PDA.

Program 5.1.3 Universal virtual DFA