Sorry for the no-op email, I don't know how it did get sent. Larry Evans wrote:
OOPS. Maybe you meant that although there were, e.g. 3 enumerators in the enumeration, the map was only defined for 2 or 1 or none. To be concrete, an example would be where enum_map<0> in the above vault code were:
template <
struct enum_map < 0
{ enum field_names { f_0 , f_1 , f_2 };
template<field_names FieldName> struct field_name {};
typedef mpl::map < mpl::pair<field_name<f_0>, type_i<0> > > field_map ; };
then I can see your point about "tuple might not map the whole enum set".
Exactly, and this is something i need (and probably is the only reason to use some kind of tag instead of indexes). In code that i wrote there were a set of functions that had similar effects and had multiple return values (as tuples). The return values weren't the same, but all of them had a common types. Some generic code had to work with this functions and needed to extract this common types from the tuples. A typed get was exactly what i needed. Fusion 'find' would probably have done the job as well, but i did not know it untill now. -- Giovanni P. Deretta Giovanni P. Deretta