Yury Selivanov wrote:
On 2012-02-03, at 1:20 PM, Guido van Rossum wrote:
Please. Let's stop this. There is no known use case to ever write
that. We're just not putting specific measures to prevent it. Writing
a = ...
Is likewise cute but not very informative. But it is valid syntax.
Well, right now you'll get TypeError if you want to raise an exception
from something that is not an exception. 'raise from None' will
loosen the check allowing None values, in the 'raise from' statement,
but that should be it.
To achieve the same effect as 'raise from ...' just do
'e.__cause__ = ...'.
On the question of using Ellipsis instead of some new singleton like
__NoContext__: how's Ellipsis semantically related to exceptions after
all?
Merrian Webster says:
---------------------
el·lip·sis
noun \i-ˈlip-səs, e-\
plural el·lip·ses\-ˌsēz\
Definition of ELLIPSIS
1
a : the omission of one or more words that are obviously understood but
that must be supplied to make a construction grammatically complete
---------------------
Relation to exceptions:
Two places to look: __context__ and __cause__
Priority? __cause__
When do we check __context__? if __cause__ is omitted (or Ellipsis)
~Ethan~
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