[Python-Dev] Multiple expression eval in compound if statement?

[Anthony Baxter]

On Monday 13 June 2005 21:14, Skip Montanaro wrote:
>     Raymond> I think it unwise to allow x to be any expression.
>
> How do you decide what's "too complex"?  Even an apparently simple variable
> can have side effects, so the semantic change bit is important no matter
> how complex the expression.  (Consider the builtin help object.  Type it at
> the prompt with no parens.)

Note also that saying 'just a simple local variable' doesn't cut it, either, 
because you will break on something like:

class stupid:
    v = 0
    def __eq__(self, other):
        self.v += 1
        return self.v == other

Really, you'd have to make sure you didn't optimise any LHS that defined
a comparision operator (I _think_ that covers all the cases).

Anthony
-- 
Anthony Baxter     <anthony at interlink.com.au>
It's never too late to have a happy childhood.