In article <4e77eae1$0$29978$c3e8da3$54964...@news.astraweb.com>,
Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> wrote:
> Westley MartÃnez wrote:
>
> > def __radd__(self, other):
> > return self.__add__(self, other)
>
> Which, inside a class, can be simplified to:
>
> __radd__ = __add__
Ooh, I could see that leading to some weird diagnostics. For example:
class Foo:
def __add__(self, other):
raise Exception
__radd__ = __add__
f1 = Foo()
print 1 + f1
produces:
./add.py
Traceback (most recent call last):
File "./add.py", line 11, in <module>
print 1 + f1
File "./add.py", line 5, in __add__
raise Exception
Exception
which leaves the user wondering why __add__() was called when clearly
__radd__() should have been. The way Westley wrote it (modulo fixing
the __add__() call signature) produces:
./add.py
Traceback (most recent call last):
File "./add.py", line 11, in <module>
print 1 + f1
File "./add.py", line 8, in __radd__
return self.__add__(other)
File "./add.py", line 5, in __add__
raise Exception
Exception
which at least is a stack trace that shows that __radd__() was called.
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