opEquals should default to opCmp (was: Re: Associative arrays in D and default comparators)

[Kirk McDonald]

Walter Bright wrote:
> Although the current AA implementation only uses opCmp, having both 
> available means that an implementation could use both or either. 
> Sometimes opEquals can be computed a lot more efficiently than opCmp.

This brings up something that has always annoyed me about 
opCmp/opEquals. While it is true that sometimes opEquals can be computed 
more efficiently than opCmp, this is not always true. Sometimes there is 
only one operation for comparison that makes sense.

I think that Object's opEquals should simply call opCmp.

class Object {
     // ...
     int opEquals(Object o) {
         return this.opCmp(o);
     }
     // ...
}

This way, a class can simply overload opCmp to overload all comparison 
operations. If it can more efficiently overload opEquals, then it is 
free to do so.

-- 
Kirk McDonald
Pyd: Wrapping Python with D
http://pyd.dsource.org