Joaquin wrote (y escribio):
Please correct if I'm wrong, but I'd say the official definition for a MPL lambda expression:
http://boost.org/libs/mpl/doc/refmanual/lambda-expression.html
actually encompasses both metafunction classes and placeholder expressions ("proper" lambda expressions, if you wish), so "lambda expression" is the common name you're after. Am I missing something? (I've got the hunch I am, actually.)
Ok, two interpretations: 1. (Mine) What the MPL documentation calls a "lambda expression" (as of the refered page) is either "placeholder expression" or meta function classes *generated* by the application of mpl::lambda, i.e., *just* the meta function classes generated in that specific way. 2. (Yours) All metafunction classes are "lambda expressions." I am admittedly biased, but I think my interpretation is the most sound one ;-) The reason for that is that I would hesitate to call an explicitly defined metafunction class, such as struct MyMeta { template<class T> apply { typedef int type; } }; a lambda expression. I still want to tell my "students" that they should implement a "metafunctor" rather than a "lambda expression," which I consider to be a proper sub set of the former :-) /David