mixin template seems to allow only declarations so if I put a if
or case-statement in the body it doesn't work. I'd like to make
something like this work:
```d
switch(code) {
case X, Y: // that specific case repeats alot in
the code in different procedures
mixin handleXY;
default:
}
```
then
```d
mixin template foo()
{
auto c = arr[i]; // arr and i are available at
switch(code)'s scope
auto m = Message(...);
switch(code)
{
case BAA_A: c.doSomething(m); break;
case BAA_B: c.doSomething(m); break;
default: assert(0, "error");
}
}
```