constructed variadic call

[Erik Smith via Digitalmars-d-learn]

Is there way to construct an "argument pack" from a non-static 
array (like the switch below)?  I need to transport a variadic 
call through a void*.

switch (a.length) {
   case 1: foo(a[1]); break;
   case 2: foo(a[1], a[2]); break;
   case 3: foo(a[1], a[2], a[3]); break;
...
}