Tobias Schwinger wrote: [1]
For now (C++89) it might be good enough to just have operator() take its arguments by non-const reference. As usually the call will be deferred and as long as the arguments are L-Values they will be deduced even if const qualified (this might break the code of the first use case above - wrapping the factory specialization into a Boost.Bind function object without actually binding anything will work around the problem, though).
[2]
Alternatively we could solve the forwarding problem (within the function object itself) using a "hammer and crowbar utility" in Fusion (overloading operator() with all combinations of templatized const/non-const reference parameters) until we have better means to do so. I personally prefer the former because it's more lightweight and might allow us to be more portable than Fusion is, however.
Have [2] for a predefined limit (say 3) and do the rest [1] for more (e.g. 3 or more). Isn't that how you did it with the fusion functional stuff? Anyway, yeah, I need such a utility, especially if it is lighweight. Regards, -- Joel de Guzman http://www.boost-consulting.com http://spirit.sf.net