On Sat, Oct 22, 2011 at 4:11 PM, Ron Adam
On Sat, 2011-10-22 at 13:32 -0700, Guido van Rossum wrote:
Thinking of str(x) as an API to get a certain value would lead there, yes. But thinking of str(x) as what gets printed by print(x), formatted by "{}.format(x)", and "%s" % s, changes things. When I am printing an object and I have no idea what type it is, I'll use repr() or "%r"; but when I know I am printing, say, an exception, I think it would be very nice if print(x) would just print its name. Just like print(None) prints 'None', it would make all the sense in the world if print(ZeroDivisionError) printed 'ZeroDivisionError', and print(type(42)) printed 'int'.
I like the part where you say...
"But thinking of str(x) as what gets printed by print(x)"
Which means (to me) that it should be what ever makes the most sense for that particular type or object. For some things, it makes sense to return __name__, while for other things, it makes sense to return something else.
There isn't a problem unless we are trying to apply a rule to *everything*.
Also it should be pointed out that not all objects have a __name__ attribute.
Correct, and that's why the proposal is strictly limited to changing str() for classes, functions and modules. (And I have to agree with Nick that it's best to just return __name__ in all three cases, rather than trying to be clever and use the qualified name.) -- --Guido van Rossum (python.org/~guido)