putStack :: GmStack -> GmState -> GmState
putStack stack' (i, stack, heap, globals, stats)
  = (i, stack', heap, globals, stats)
putStack :: GmStack -> GmState -> GmState
putStack stack' (i, stack, heap, globals, stats)
  = (i, stack', heap, globals, stats)
putStack stack' (i, stack, heap, globals, stats)
  = (i, stack', heap, globals, stats)