"David Abrahams" <dave@boost-consulting.com> wrote
Joel de Guzman <joel@boost-consulting.com> writes:
Doug Gregor wrote:
result_of<Op(A, B)>::type
I think this is the best interface I've seen so far. The result_of_plus is just a temporary solution while waiting for Doug's result_of work which was not available at the time.
...which is just a temporary solution while we wait for decltype?
Apologies, its not clear from the subject. I am referring to operations, which have more attributes than just the type of the result. For example a multiplication maybe commutative in one context, but not in another. This sort of information could be used by an optimizer walking about in an expression template for example. stream output of the symbol for the particular operator provides a simple way of debugging in generic code. A "super-functional" functor with specialisable traits would provide a common mechanism for specializing operations for UDT's. IOW A way for the UDT designer to communicate their intent to users of operations on their types and how they interact with other types. At the simplest level for example, communicating whether an operation between two types from different libraries is supported. So there is more to it than just decltype. I am talking about operations rather than types after all. regards Andy Little