a = b = 1 just syntactic sugar?

[Ed Avis]

Robin Munn <rmunn at pobox.com> writes:

[example of a = b = [] versus separate assignments]

>It seems the RHS is only evaluated once in chained assignment, at
>least as of Python 2.2.2.

Yes, it has to be this way.  You can think of [] as a function which
returns a new list.  If the RHS were evaluated twice in

    a = b = []

then [] would be called twice and you'd get two different lists (as
happens when there are two different assignment statements).

-- 
Ed Avis <ed at membled.com>