Larry Hastings wrote:
> The control-flow exclusion is for /module//attribute/ or /class
> attribute/ annotations:
> class C:
> if random.random() > 0.5:
> my_attr:int=3
> else:
> my_attr2:float=3.5
That very example would be helpful in the FAQ, though I understand if you're
concerned about making a minor sub-section seem too long.
If I understand correctly, the problem is that you can't store multiple
alternative annotations on my_attr. Therefore:
class C:
my_attr:(int if random.random > 0.5 else float)
should be OK, because there is only a single annotation.
What about optional attributes, like:
class C:
if random.random() > 0.5:
my_attr:int=3
Also, would (conditionally defined) function variable attributes become a
problem if they were actually stored? (Take Larry's class example, and make if
a def instead of a class statement.)
My (weakly held, personal) opinion is that these restrictions would be
reasonable, and a single release of deprecation would be enough, but it would
be better if that code could trigger a deprecation warning during that release,
even for code that hasn't done the future import. It would also be OK to just
say "implementation-defined behavior; CPython 3.x ignores the annotation"
instead of banning them.
-jJ
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