[Python-ideas] SyntaxWarning for for/while/else without break or return?

Terry Reedy tjreedy at udel.edu
Sun Oct 11 06:09:40 CEST 2009

Nick Coghlan wrote:
> Steven D'Aprano wrote:
>>> The point of a warning is very much that the code works and is legal,
>>>   but *in most case* is not what people would want. 
>> Can you give any examples in the Python standard library where code 
>> raises a warning on such a basis?
>> I would be shocked if you can give any examples.
> See my other post - there are currently 3 in the 2.x branch. Two of them
> are pure style warnings strongly encouraging people to put their global
> statements at the beginning of the function,

If it is perfectly legal to put global statements anywhere in the 
function, and there is no intention to tighten the rule to disallow that 
(which would be ok with me), then I am against the warning. It suggests 
that one has done something wrong, when one has not.

A global statement as module level has no effect, even though some 
newbies think it does (else why would they write it when they do?). 
Perhaps we should add a warning for *that*, especially given that it is 
more likely to indicate a real error of thinking rather and simply 
making the 'wrong' stylistic choice.

> In this thread, the proposal is that we encourage people to only use the
> else clause on loops containing at least one break statement.

Whereas I want to be able to use while/else and for/else in didactic 
code without having to warn people against a spurious warning.

Terry Jan Reedy

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