[Python-Dev] Adding a conditional expression in Py3.0
tjreedy at udel.edu
Sat Sep 24 03:48:39 CEST 2005
>> Need I continue? Or is the dead still dead?
Since 'a if b else c' is not obviously dead, I will summarize my argument
against it thusly:
It is ambiguous to people because it is can be parsed (by people, who are
not automatons) as either '(a if) b (else c)' or 'a (if b) (else c)'. The
first parsing, seeing a as the conditional rather than the consequent, as
in the the second, is at least as reasonable as the second given precedents
in both other algorithm languages and natural languages (in English, at
least, but I suspect others also).
Ambiguity sometimes leads to discomfort. As important, it sometimes leads
to bugs either in writing or reading. The impetus for this discussion was
a real-life buggy example of the and/or construct. Its replacement should
be something not similarly bug-prone, even if for a different reason.
Terry J. Reedy
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