On Dec 4, 2008, at 2:05 PM, Simonson, Lucanus J wrote:
These operators are overloaded with SFINAE on return type such that three intersection operators are sufficient to cover all valid combinations of any geometry type, rectangle, six flavors of polgyons with and without holes in the manhattan, 45, or general domains, and std containers thereof as well as my data structures that serve as the inputs to the boolean algorithms
Gordon wrote:
This approach leads to an combinatorial number of overloads, does it not? Surely there must be a way to do static multiple dispatch using metaprogramming instead.
No, there are three algorithms and three overloads. Any combination of many possible inputs resolves to the correct algorithm through metaprogramming. This operator API is concepts based. Previously I had a real problem with tag dispatching leading to exactly the problem you call out where a combinatorial number of overloads was required. Concepts is much more powerful than tag dispatching and got the number of functions I needed to type down to linear to the number of algorithms I wanted to expose. As it is I got a repetitive stress injury from typing typename, typedef ::type the < > and _ chars and saving ever twenty seconds with :w because I'm a vi user. Regards, Luke