Hi Matthieu, On Wed, Feb 11, 2009 at 09:22:47AM +0100, Matthieu Brucher wrote:
template<class Child> struct MyfStruct { typename boost::enable_if<has_i<Child>::type, ...>::type f() { // Do some stuff, but I don't know how to call i(), you will have to test :| } };
where has_i<> tests if the child has the method i().
Then, if you find how to call i() from the f() method, you just have to write:
class MyClass: public MyfStruct<MyClass> { void i(); // f() will be callable now };
Thanks for your example. Yet I believe, that the solution you propose does not solve the underlying problem: as the compiler errors indicate, struct bar (or in your example, class MyClass) is incomplete at the time when has_i<Child> [*] is called. Hence, bar/MyClass cannot use CRTP to automatically derive functions from foo/MyfStruct. I will have to use a different approach to inject functions conditionally. Matthias [*] This would factor out the code that checks whether T has i(): template <typename T> struct has_i : boost::mpl::bool_<boost::is_function<typename T::i>::value> {}; -- Matthias Vallentin vallentin@icsi.berkeley.edu http://matthias.vallentin.cc