Operator commutativity
Henrik Faber
hfaber at invalid.net
Mon Sep 19 07:11:51 EDT 2011
Hi there,
when I have a python class X which overloads an operator, I can use that
operator to do any operation for example with an integer
y = X() + 123
however, say I want the "+" operator to be commutative. Then
y = 123 + X()
should have the same result. However, since it does not call __add__ on
an instance of X, but on the int 123, this fails:
TypeError: unsupported operand type(s) for +: 'int' and 'X'
How can I make this commutative?
Best regards,
Henrik
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