WAT: opCmp and opEquals woes

[via Digitalmars-d]

On Monday, 28 July 2014 at 00:23:36 UTC, H. S. Teoh via 
Digitalmars-d wrote:
> On Sun, Jul 27, 2014 at 07:04:08PM +0000, Fool via 
> Digitalmars-d wrote:
>> Similarly, the user is free to define opCmp without 
>> restriction. In
>> practice, however, it does not seem to make any sense if <= 
>> does not
>> even model a preorder (reflexive and transitive) or one of >, 
>> <=, <
>> does not match.
>
> The problem with imposing these kinds of restrictions, is that 
> they are
> generally not enforceable (at least, not without significantly 
> crippling
> legitimate use cases). At some point, we have to stop 
> babysitting the
> programmer and trust that he's competent enough to not try to 
> subvert
> the language to make it do stuff it wasn't intended to do.

That's missing the point completely. If the compiler cannot 
obtain meta information about the properties of relations then 
you cannot introduce high level optimization and generic 
programming becomes crippled and a second rate citizen.