switch case for constants-only?

[Don]

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. 

Switch with constant values is completely different to a switch 
statement with variables -- it's reasonable to expect O(1) case 
comparisons if all the values are known at compile time, but I think 
that's impossible with variable cases.
Allowing switch with variable cases at the expense of constant cases 
would be a real PITA for non-dynamic code. You'd need some way of 
handling both.