On 5/18/06, David Abrahams <dave@boost-consulting.com> wrote: I imagine this sort of usage is pretty common. The problem is that it's hard to initialize this member efficiently: you have to build and copy too many compressed_pairs. I propose to extend compressed_pair with overloaded ctors, as follows: compressed_pair( first_param_type f , typename second_type::first_param_type sf , typename second_type::second_param_type ss); compressed_pair( first_param_type f , typename second_type::first_param_type sf , typename second_type::second_type::first_param_type ssf , typename second_type::second_type::second_param_type sss ); ... etc. If SFINAE doesn't take out these declarations when the second type is not a (compressed_)pair, we can always template them. ________ SFINAE would not come into play with just overloaded constructors, regardless of the fact that they are constructors of a template instantiation. The constructors would have to be templates themselves. Correct me if I'm missing something, but would it not be better to just have a compressed_tuple template, or are there reasons I am missing? -- -Matt Calabrese