Overloaded '<' operator in subsets.Range class

[meshtag]

I am trying to add support for memlet range overlap warning(in context of #424) and my solution involves sorting a list of elements of type subsets.Range. For using python's inbuilt sorting function, I can overload '<' operator for subsets.Range class or provide a custom compare function specifically for that call site. Which one is more feasible?

[tbennun]

Great idea, thanks. I see two issues with the check as it is implemented right now:

1. there needs to be some exception raised if the ranges are symbolic and cannot be compared (this is likely already happening)
2. Since comparing 2-tuples is not well defined, I personally think that ranges should be compared by their starting element and then their ending element, rather than end element only.

[meshtag]

For the second point, do you mean something like this :

def __lt__(self, other):
        if (self.min_element() < other.min_element()):
            return 1
        elif (self.min_element() > other.min_element()):
            return 0
        else:
            if (self.max_element() < other.max_element()):
                return 1
            else:
                return 0

[tbennun]

yes, though comparisons should return boolean values.