[Python-3000] removing destructuring del

[Alexander Belopolsky]

Guido van Rossum <guido <at> python.org> writes:

> 
> On Thu, Feb 21, 2008 at 11:27 PM, Andrew Dalke
> <dalke <at> dalkescientific.com> wrote:
> .. I think this should not be legal
> >
> >  del a, (b, c)
> >
> >  That should raise
> >
> >    SyntaxError: can't delete tuple
..
> These all make sense to me, but at the same time it seems such a minor
> issue that I'm not sure we should bother. It would probably end up
> being more custom syntax -- right now it just uses exprlist in the
> grammar and is limited to assignment targets by the compiler.
> 

I was always wondering why both lists and tuples are allowed as
assignment targets.  As far as I can tell, the only difference is in
the corner cases such as

>>> del []
>>> del ()
  File "<stdin>", line 1
SyntaxError: can't assign to ()
>>> [] = ()
>>> () = ()
  File "<stdin>", line 1
SyntaxError: can't assign to ()

Maybe Py3k should eliminate the list form, but allow empty tuples
as useful in auto-generated code (deleting variable number of
names.)