Peter Otten <[EMAIL PROTECTED]> writes:
> > all_heights = (block.height for block in stack if block.is_marked())
> > if is_empty(all_heights):
> > raise SomeError("No marked block")
>
> Such a function would have to rebind the generator:
Yeah, that's what I mean about generators not working the right way.
> You can make it work, but the result tends to be messy:
I think it's better underneath, but still syntactically ugly, to just
defer the generator creation:
all_heights = lambda:
(block.height for block in stack if block.is_marked())
if is_empty(all_heights ()):
raise SomeError("No marked block")
height = sum(all_heights ())
Now sum and is_empty see two separate generators, so is_empty is
straightforward:
def is_empty(gen):
try:
gen.next()
return True
except StopIteration:
return False
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