Return enum-templated struct based on runtime value

[Sebastian Graf]

Hi,

I wonder if there is a good way to dry up this:
    enum Machine
    {
        I386,
        AMD64
        // , ...
    }

    template machineWord(Machine machine)
    {
        static if (machine == Machine.I386)
        {
            alias machineWord = uint;
        }
        static if (machine == Machine.AMD64)
        {
            alias machineWord = ulong;
        }
    }

    ulong foo(Machine machine)
    {
        if (machine == Machine.I386)
        {
            machineWord!(Machine.I386) m = (1 << 32)-1;
            m++;
            return m;
        }
        else // assume AMD64
        {
            machineWord!(Machine.AMD64) m = (1 << 32)-1;
            m++;
            return m;
        }
    }

Essentially, I am doing the same with each machine type, but it 
has different semantics for each of them. I hope you see this is 
a valid use case and a way to remove duplication.
Something à la specify the enum members to switch on to a 
template together with a templated function and then do some 
compile time magic to expand the code to invoke the appropriate 
specialization.