switch case for constants-only?

[BCS]

Hello Nick,

> "Sean Kelly" <sean at invisibleduck.org> wrote in message
> news:hfelka$rhf$1 at digitalmars.com...
> 
>> Nick Sabalausky Wrote:
>> 
>>> I just noticed in D1 that the values for the cases in a switch must
>>> be
>>> known
>>> at compile-time (btw, the docs don't seem somewhat vague on that).
>>> Is
>>> this
>>> also true in D2? If so, I don't suppose we could get that changed
>>> before
>>> the
>>> book? It's a real PITA for dynamic code.
>> int x = 1, y = 1;
>> 
>> switch( z )
>> {
>> case x:
>> ...
>> case y:
>> ...
>> }
>> What should this do?  Throw an exception perhaps?
>> 
> As I mentioned earlier, that should be semantically equivilent to:
> 
> int x = 1, y = 1;
> 
> if(z == x)
> { ... }
> else if(z == y)
> { ... }
> In fact, it's already semantically equivilent to that, except that x
> and y are currently required to be known at compile-time.
> 

Just jumping a ways down this rabbit hole...

struct S { int i; int opCmp(S s) { return i-- == s.i++; }

{
    S a,b,c,d,e; 
    ...
    switch(a)
    {
        case b: break;
        case c: break;
        case d: break;
        case e: break;
    }
}

Oh, boy. What the hack does the above do?