Brett C. wrote:
> Guido van Rossum wrote:
>>PEP 340 is still my favorite, but it seems there's too much opposition
>>to it, so I'm trying to explore alternatives; at the same time I
>>*really* dislike the complexities of some of the non-looping
>>counterproposals (e.g. Nick Coghlan's PEP 3XX or the proposals that
>>make every keyword associated with 'try' a method).
>>
>
>
> Nick's was obviously directly against looping, but, with no offense to Nick,
> how many other people were against it looping? It never felt like it was a
> screaming mass with pitchforks but more of a "I don't love it, but I can deal"
> crowd.
PEP 340 is very nice, but it became less appealing to me when I saw what
it would do to "break" and "continue" statements.
text = 'diamond'
for fn in filenames:
opening(fn) as f:
if text in f.read():
print 'I found the text in %s' % fn
break
I think it would be pretty surprising if the break didn't stop the loop.
Here's a new suggestion for PEP 340: use one keyword to start a block
you don't want to loop, and a different keyword to start a block that
can loop. If you specify the non-looping keyword but the block template
produces more than one result, a RuntimeError results. Here is example
A, a non-looping block statement using "try":
text = 'diamond'
for fn in filenames:
try opening(fn) as f:
if text in f.read():
print 'I found the text in %s' % fn
break
In example A, the break statement breaks the "for" loop. If the
opening() iterator returns more than one result, a RuntimeError will be
generated by the Python interpreter.
Here is example B, a looping block statement using "in", adapted from
PEP 340:
in auto_retry(3, IOError) as attempt:
f = urllib.urlopen("http://python.org/peps/pep-0340.html";)
print f.read()
Note that I introduced no new keywords except "as", and the syntax in
both cases is currently illegal.
Shane
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