Shane Hathaway wrote:
> For each block statement, it is necessary to create a *new* iterator,
> since iterators that have stopped are required to stay stopped. So at a
> minimum, used-defined statements will need to call something, and thus
> will have parentheses. The parentheses might be enough to make block
> statements not look like built-in keywords.
Definitely true for generators. Not necessarily true for iterators in
general::
class Example(object):
value = 0
result = False
def __iter__(self):
return self
def next(self):
self.result = not self.result
if self.result:
self.value += 1
return self.value
else:
raise StopIteration()
::
>>> e = Example()
>>> list(e)
[1]
>>> list(e)
[2]
>>> list(e)
[3]
It might actually be workable in the transaction scenario, as well as
others. I'm not sure if I love or hate the idea though.
Another thing. In the specification of the Anonymous Block function, is
there a reason that "itr = EXPR1" instead of "itr = iter(EXPR1)"? It
seems to be a dis-symmetry with the 'for' loop specification.
Thanks,
-Shane (Holloway) ;)
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