Suggestions for 2002

[Mark McEahern]

> "Raymond Hettinger" <othello at javanet.com> writes:
> Suggestion #1:   Issue a dubious syntax warning for multiple
> assignments where there are overlaps between the assigned-to
> variables:
>
> >>> a = ['cat','dog']
> >>> i = 1
> >>> i, a[i] = 0, 'boo'
> >>> a
> ['boo', 'dog']        # not ['cat','boo'] which was expected
>
> I'd call this an outright Python bug even if it's documented in the
> reference manual.  What's the justification?  From the doc, it appears
> that even x,y=y,x only works for fairly subtle reasons.  This seems
> bogus.  It would be better if assigning a sequence made a temporary
> sequence of the target values before assigning.

What would you expect here (breaking the multiple assignment up into
separate assignment)?

>>> a = ['cat','dog']
>>> i = 1
>>> i = 0
>>> a[i] = 'boo'
>>> a

Clearly, you'd expect ['boo', 'dog'].

So where's the problem?

// mark