---------------------------------------------------------------------
-------------------------- The Evaluator ----------------------------
---------------------------------------------------------------------

evalVar x ((y, v):sto) 
  | x == y
  = v
  | otherwise
  = evalVar x sto
evalVar x ((y, v):sto) 
  | x == y
  = v
  | otherwise
  = evalVar x sto
evalVar x ((y, v):sto) 
  | x == y
  = v
  | otherwise
  = evalVar x sto