On 1/28/2010 3:37 AM, Paul Rubin wrote:
Jonathan Gardner<jgard...@jonathangardner.net> writes:
If you're going to have statements, you're going to need the null
statement. That's "pass".
Why? Expressions are statements, so you could just say "pass" (in
quotes, denoting a string literal), or 0, or None, os anything else like
that, instead of having a special statement.
As Python is currently compiled, you are right, pass is not needed.
A string becomes the doc attribute, and becomes local var 0, but 0 is
just ignored. I actually expected a load_const but that is now optimized
away. I am not sure this was always true. Perhaps 'pass' is easier than
'0' for mewcomers reading the tutorial, but I have no data.
>>> def f(): ''
>>> def g(): pass
>>> def h(): 0
>>> from dis import dis
>>> dis(f)
1 0 LOAD_CONST 1 (None)
3 RETURN_VALUE
>>> dis(g)
1 0 LOAD_CONST 0 (None)
3 RETURN_VALUE
>>> dis(h)
1 0 LOAD_CONST 0 (None)
3 RETURN_VALUE
>>> f.__doc__
''
>>> g.__doc__
>>>
Terry Jan Reedy
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