+ elif opcode == 147: # decrement
+ value = stack.pop()
+ assert isinstance(value, int)
+ stack.append(value - 1)
+ elif opcode == 149: # typeof
+ value = stack.pop()
+ return {
+ _Undefined: 'undefined',
+ compat_str: 'String',
+ int: 'Number',
+ float: 'Number',
+ }[type(value)]