[Python-3000] __nonzero__ vs. __bool__

[Walter Dörwald]

tomer filiba wrote:
> patch updated

You're fast! ;)

AFAICT now we have the following problem: If
Objects/typeobject.c::slot_nb_bool() falls back to using __len__(), the
return value of __len__() must be a bool.

Servus,
   Walter

> On 11/21/06, *Guido van Rossum* <guido at python.org
> <mailto:guido at python.org>> wrote:
> 
>     I think it would set a good example if __bool__ was *required* to
>     return exactly True or False and no other object, not even int
>     instances equal to 0 or 1. Surely that can't be much of a burden. Feel
>     free to upload an improved patch.
> 
>     On 11/21/06, Walter Dörwald <walter at livinglogic.de
>     <mailto:walter at livinglogic.de>> wrote:
>     > Guido van Rossum wrote:
>     > > On 11/21/06, Ivan Krstić < krstic at solarsail.hcs.harvard.edu
>     <mailto:krstic at solarsail.hcs.harvard.edu>> wrote:
>     > >> Guido van Rossum wrote:
>     > >>> Can anyone help out evaluating this patch? If it has to wait
>     for me
>     > >>> it's gonna be a looooooong wait...
>     > >> Looks fine to me functionally, although it seems to
>     gratuitously retab
>     > >> some code that used to be aligned with tabstop 8 to a tabstop of 4.
>     > >
>     > > Thanks! I hope you meant "indentation level" instead of "tabstop".
>     > > Tomer, can you fix the indentation to be whatever's prevailing
>     in the
>     > > file you're editing?
>     >
>     > Another question is whether __bool__() should be allowed to return an
>     > int (or any other object), or if it *must* be a bool. (The patch
>     > currently allows ints). What if __bool__() returns subclasses of int,
>     > that overwrite __bool__() themself?
>     >
>     > Servus,
>     >    Walter
>     >
>     >
> 
> 
>     --
>     --Guido van Rossum (home page: http://www.python.org/~guido/)
> 
>