Tuples and the ''C++ tuple protocol'' build upon variadic arguments
and are thus rather tedious to handle, especially in this situation here,
where the argument can ''sometimes be a tuple...''
Several years ago I made the observation that processing by explicit ''type sequences''
(Loki-style) is much simpler to handle and easier to lift to a generic level of processing.
Thus I'll attempt now to extract the ''iteration and extraction part'' of the logic into a new helper.
`lib::meta::ElmTypes<TUP>` allows to process all ''tuple-like types'' and generic ''type sequences'' uniformely
and enables to use both styles interchangably (btw, it is quite common to ''abuse'' `std::tuple` as a type sequence).
With this helper, we can now
- build a ''type sequence'' from any ''tuple-like'' object (and vice-versa)
- re-bind (i.e. transfer the template parameters to another template)
- apply some wrapper
- create AND / OR evaluations over the types
Ichthyostega
844aa7f3d7