[EMAIL PROTECTED] a écrit :
Bruno Desthuilliers dixit :
Boris Borcic a écrit :
Given the ABC innovation, maybe an infix syntax for isinstance() would
be good.
Possibilities :
- stealing "is" away from object identity. As a motivation, true use
cases for testing object identity are rare;
"x is None" is a *very* common test. Using a _marker object as default
arg value when you want to accept None as a meaningfull value is pretty
common.
(a) Okay, 3to2 can take care of "x is NoneType" and/or "x == None".
The latter could also be a compiler optimization.
(b) Give me None==False
Why so ?
and in exchange I will adopt "x is None" as
sacred forever :)
(not quite BTW, how much future do you think is there in turning 2to3
into some usable 3to2 ? What about "NtoM" as a more generic Python
project ?)
Testing a class identity often happens when writing metaclasses
This kind-of-talks for Terry's proposition : adding a __contains__ to
type,
I said "type identity testing", not isinstance() or issubclass() testing.
(snip)
A intriguing wider proposition would be to transpose Ruby's notion of
"Open Classes" to Python built-in metaclasses (or just to type
itself ?).
No, thanks. Even the Ruby guys start to think making evrything open may
not be such a good idea after all.
And anyway, I don't see how any of the above address the point that your
premise that "true identity testing is rare" is just wrong...
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