ProtoObject and comparison for equality and ordering

[Noob]

Any thoughts about the spaceship operator design as accepted for 
C++20?

Not invented here, but there seems to be room for improvement:

https://stackoverflow.com/q/47485803

On Wednesday, 15 May 2019 at 00:32:32 UTC, Andrei Alexandrescu 
wrote:
> ---
> import std.stdio;
>
> struct OverengineeredCmpResult {
>     enum R { lt, eq, gt, ionno }
>     private R payload;
>     int opCmp(int alwaysZero) {
>         writeln("b");
>         return 0;
>     }
> }
>
> struct A {
>     OverengineeredCmpResult opCmp(A rhs) {
>         writeln("a");
>         return 
> OverengineeredCmpResult(OverengineeredCmpResult.R.ionno);
>     }
> }
>
> void main() {
>     A a, b;
>     if (a < b) {}
> }
> ---