Steven D'Aprano wrote: > I thought that overflow errors would be a thing of the past now that > Python automatically converts ints to longs as needed. Unfortunately, > that is not the case. > >>>> class MyInt(int): > ... pass > ... >>>> MyInt(sys.maxint) > 2147483647 >>>> MyInt(sys.maxint+1) > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > OverflowError: long int too large to convert to int > > > How do I subclass int and/or long so that my class also auto-converts > only when needed? > > >
Use __new__. py> import sys py> py> class MyLong(long): ... pass ... py> class MyInt(int): ... def __new__(cls, *args, **kwargs): ... try: ... return int.__new__(cls, *args, **kwargs) ... except OverflowError: ... return MyLong(*args, **kwargs) ... py> MyInt(sys.maxint**2) 4611686014132420609L py> type(_) <class '__main__.MyLong'> James -- http://mail.python.org/mailman/listinfo/python-list
