Idea for more delegations in <algorithm>

[Paolo Carlini]

Gabriel Dos Reis wrote:

>| ... but, thinking more about this, probably the real issue is with
>| *defaults* not with __enable_if "per se".
>
>Yes.  Usually, the enable_if<> stuff is put in the return type.
>Constructors don't have return type, so you would have to stick it
>somewhere. 
>  
>
Right. However, if I'm not mistaken, even in case of constructors, you can
simply call from the constructor two helpers, with no added tags, and gain
one less level of unnecessary indirection and no annoying empty structs.

Paolo.