Ideally,
struct S { int a; int b; }
void foo(int p, int q);
S s;
foo(s);
should work (setting aside for the moment that they are
different types). Unfortunately, the variety of function
calling ABIs makes this impractical.
So tuples in a language like D that must conform to external
ABIs is that tuples will always have some rough edges.
Why not simply introduce an "expand" property for structs?
----
foo(s.expand) //equivalent to foo(s.a,s.b)
----
That would be the exact analogous of expand for tuples and would
maintain a sane type system .
