can't rebind magic methods

Michael Tobis mtobis at gmail.com
Tue Mar 21 00:48:17 CET 2006


Still a bit confused actually. Any explanation of the following?

mt

####

def getf(method,name):
    def f(self, *a, **k): return method(self.val, *a, **k)
    f.func_name = name
    return f

class myint(object):
    def __init__(self, val):
        self.val = int(val)

for spec in 'str repr hash hex oct pow add'.split():
    name =  '__%s__' % spec
    method = getattr(int, name)

    # comment this out to get the non-working case

    setattr(myint,name,getf(method,name)) # works


    # uncomment three lines to get the non-working case
    # raises TypeError: "expected 1 arguments, got 0" at method
invocation
    # why isn't this equivalent to the setattr above?

    # def f(self, *a, **k): return method(self.val, *a, **k)

    # f.func_name = name

    # setattr(myint,name,f) # doesn't work


if __name__ == "__main__":
   a = myint(42)
   print a
   print oct(a)




More information about the Python-list mailing list