[Python-Dev] SyntaxError: can't assign to function call
Guido van Rossum
guido at python.org
Wed Aug 9 22:41:07 CEST 2006
On 8/9/06, Georg Brandl <g.brandl at gmx.net> wrote:
> Terry Reedy wrote:
> > "Neal Becker" <ndbecker2 at gmail.com> wrote in message
> > news:ebd2sp$nnv$1 at sea.gmane.org...
> >> class X (object):
> >> pass
> >> X() += 2
> >>> SyntaxError: can't assign to function call
> >> Suppose I actually had defined __iadd__ for class X. Python says this
> >> syntax is invalid. I wish is wasn't.
> > If you translate to x() = x() +2, with x called just once, it does not make
> > sense. You can bind to names and slots in compound objects, but not to
> > objects.
> This is similar to
> x = (, 2)
> x += 
> which doesn't currently work either, though it could.
No it couldn't. You can't assign to x. L += R is defined as L =
L.__iadd__(R) so L must be a valid assignment target.
--Guido van Rossum (home page: http://www.python.org/~guido/)
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