why pass statement?

M-a-S NO-MAIL at hotmail.com
Wed Sep 17 00:30:03 CEST 2003


"Hans Nowak" <hans at zephyrfalcon.org> wrote in message news:mailman.1063743501.23038.python-list at python.org...
> 'pass' is a no-op statement that, according to the tutorial, is used when a
> statement is required syntactically but the program requires no action.

I know. I just state that there is NO need for it. Just define in __builtins__
pass = None and that's it.

BTW Algol-68 used 'skip' for both purposes (no action and no data).


> Your code, using None, has the same effect.  However, there's a slight
> difference in the bytecode that is generated:
>
>  >>> def f(): pass
> ...
>  >>> def g(): None
> ...
>  >>> import dis
>  >>> dis.dis(f)
>    1           0 LOAD_CONST               0 (None)
>                3 RETURN_VALUE
>  >>> dis.dis(g)
>    1           0 LOAD_GLOBAL              0 (None)
>                3 POP_TOP
>                4 LOAD_CONST               0 (None)
>                7 RETURN_VALUE
>
> This is probably irrelevant, but it wouldn't be correct to say that using pass
> is exactly the same as using None.
>
> HTH,
>
> -- 
> Hans (hans at zephyrfalcon.org)
> http://zephyrfalcon.org/


That's just a question of optimization.

And thank you for showing me how to dig to the code!

M-a-S






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