Re: Extend D's switch statement?

[Timon Gehr via Digitalmars-d]

On 07/08/2015 10:31 AM, Martin Nowak wrote:
On Wednesday, 8 July 2015 at 07:15:27 UTC, Yuxuan Shui wrote:
I think it will be useful to extent switch statement to support any
type that implements opEquals and opHash.
Is there any technical difficulties to implement this?

Hardly anyone wants switch to be a better if-else ladder.
https://issues.dlang.org/show_bug.cgi?id=5862

I don't think this is what is being asked for.

switch(x){
    case a:
        ...;
        break;
    case b:
        ...;
        break;
    default: break;
}

->

switch(x.toHash()){
    case a.toHash():
        if(x!=a) goto default;
        ...;
        break;
    case b.toHash():
        if(x!=b) goto default;
        ...;
        break;
    default: break;
}

(a and b are known at compile time here, and so are their hash values. 
Hash collisions between e.g. a and b would need to be dealt with of course.)