Python: defining my own operators?

Question

I have a bot in python that allows the users to evaluate mathematical expressions (via a set of safe functions), but I would like to define my own operator. Does python support such a thing?

Answer 1

no, python comes with a predefined, yet overridable, set of operators.

Answer 2

No, you can't create new operators. However, if you are just evaluating expressions, you could process the string yourself and calculate the results of the new operators.

Answer 3

If you intend to apply the operation on a particular class of objects, you could just override the operator that matches your function the closest... for instance, overriding __eq__() will override the == operator to return whatever you want. This works for almost all the operators.

Answer 4

While technically you cannot define new operators in Python, this clever hack works around this limitation. It allows you to define infix operators like this:

# simple multiplication
x=Infix(lambda x,y: x*y)
print 2 |x| 4
# => 8

# class checking
isa=Infix(lambda x,y: x.__class__==y.__class__)
print [1,2,3] |isa| []
print [1,2,3] <<isa>> []
# => True