[Python-Dev] pre-PEP: Resource-Release Support for Generators (original) (raw)

Phillip J. Eby pje at telecommunity.com
Mon Sep 15 11:26:27 EDT 2003

At 11:48 AM 9/15/03 +0100, Armin Rigo wrote:

Hello Samuele,

On Sat, Sep 13, 2003 at 04🔞51PM +0200, Samuele Pedroni wrote: > OTOH conflating 'with' and 'for' just for generators seems a rather ad-hoc > breaking of > orthoganility of the two, you could not write anymore code like this: > > g = gen() > for v in g: > ... do something up to a point ... > ... > for v in g: > ... I had thought about this. This occurs when you 'break' out of the first loop. I would say that NOT calling the exit() method in this specific case seems quite intuitive, the 'break' meaning 'just exit from the loop now without any further processing, skipping the 'else' part if present'.

Hmmm... You realize this is also going to break the similarity between:

i = iter(something) while 1: try: j=i.next() except StopIteration: break

and

for j in iter(something): pass

The former is already complex enough as a mental model. I think it gets altogether too complex if one also has to consider the enter/leave issue. This strikes me as an area like try/except vs. try/finally: it really should be a separate block, just for the sake of explicitness. As much as it would be cool to have the automatic release, I think I'd rather use:

with i = iter(something): for j in i: ...

And make the resource management very visible.

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