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Traits

NOTE: These examples use embedded-friendly estd::basic_ostream. Don't be afraid of the out reference!

Traits: single PGN

template <pgns pgn>
void print_pgn_name()
{
    out << embr::j1939::pgn::traits<pgn>::name() << endl;
}

Traits: multiple SPNs (fold expression)

template <spns spn>
void print_spn_name()
{
    out << embr::j1939::spn::traits<spn>::name() << endl;
}

Traits: multiple SPNs (estd::variadic)

Since c++11 doesn't have fold expressions, a different approach is required to compile-time iterate. Fortunately, estd::variadic::values helps with this.

template <spns spn>
void print_spn_name()
{
    out << embr::j1939::spn::traits<spn>::name() << endl;
}

template <pgns pgn>
void print_spn_names()
{
    using pgn_spns = embr::j1939::pgn::traits<pgn>::spns;
    
    out << embr::j1939::spn::traits<spn>::name() << endl;
}

See TBD for estd documentation on the subject (malachi-iot/estdlib#44 )

Dispatch

What amounts to a tuned switch statement, the dispatch mechanism is a convenient way to translate a run time PGN# into a compile time PDU.

be careful, Dispatch can produce a lot of code spew

See Concepts for breakdown of internal Dispatch behavior

Dispatch: to_string