if statement, with function inside it: if (t = Test()) == True:

[MRAB]

Rhodri James wrote:
> On Mon, 04 May 2009 15:25:44 +0100, Antoon Pardon 
> <apardon at forel.vub.ac.be> wrote:
> 
>> On 2009-04-24, Steven D'Aprano <steve at REMOVE-THIS-cybersource.com.au> 
>> wrote:
>>> On Fri, 24 Apr 2009 03:00:26 -0700, GC-Martijn wrote:
>>>
>>>> Hello,
>>>>
>>>> I'm trying to do a if statement with a function inside it. I want to 
>>>> use
>>>> that variable inside that if loop , without defining it.
>>>>
>>>> def Test():
>>>>     return 'Vla'
>>>>
>>>> I searching something like this:
>>>>
>>>> if (t = Test()) == 'Vla':
>>>>     print t # Vla
>>>>
>>>> or
>>>>
>>>> if (t = Test()):
>>>>     print t # Vla
>>>
>>> Fortunately, there is no way of doing that with Python. This is one
>>> source of hard-to-debug bugs that Python doesn't have.
>>
>> I think this is an unfortunate consequence of choosing '=' for the
>> assignment. They could have chosen an other token to indicate an
>> assignment one that would have made the difference between an
>> assignment and a comparison more visually different and thus
>> bugs by using one while needing the other less hard to track
>> down.
> 
> What token could be used and still be meaningful, though?  Algol
> used ":=", which has most of the same problems as "=" (more, in my
> opinion, since it fools the eye more easily if you're scanning
> printed code quickly).  Easily constructed arrows like "<=" or
> "<-" collide with different comparators.  About all that's left
> that even vaguely implies assignment is "~", and it's no better.
> 
If you're not limited to ASCII then there's '←' (U+2190, 'LEFTWARDS
ARROW'). It's a little too late now, though.