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

[Georg Brandl]

Gerald Britton schrieb:
> Based upon Guido's post in this thread, I think the chances of getting
> such a warning are between slim and none.

I don't read the post that way.  Changing for/else's semantics, or removing
the else clause entirely won't happen, yes.  But

>  And, I'm very happy about
> that.  In fact, I would be extremely unhappy if a program that has
> worked for 20 years (Guido's number, not mine) would suddenly start to
> spurt warnings just because I upgraded Python.

Sorry, but that happens often enough, e.g. when new keywords are added.

> Bad idea all round.

That's a very presumptuous statement.  There is quite a heavy argument in
favor, namely prevention of bugs for people who misunderstand how for/else
works, see your initial examples.  These bugs can be nasty, because they are
triggered by a corner case.

An example from a different language is mixing of && and || without parens,
which GCC warns about.  The syntax is valid C, but I assume the warning exists
because the bugs it prevents weigh more than the irritation it causes in
some developers.

Georg


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