Hello.

I want to create some finite algebra, where the elements are enumerated but operations on them are defined (with composition tables).

e.g.:

enum color = { white, yellow, red, blue, orange, violet, green, black };

color a = blue;
a += yellow;
assert(a == green);

is this possible in D?

Because, if I define a struct, I can define operation overloads, but then I have no enumeration of possible values. But if I enumerate, I cannot
overload operations.
What have I missed?

On Monday, 26 May 2014 at 16:54:02 UTC, Dominikus Dittes Scherkl wrote:
> Hello.
>
> I want to create some finite algebra, where the elements are enumerated but operations on them are defined (with composition tables).
>
> e.g.:
>
> enum color = { white, yellow, red, blue, orange, violet, green, black };
>
> color a = blue;
> a += yellow;
> assert(a == green);
>
> is this possible in D?
>
> Because, if I define a struct, I can define operation overloads, but then I have no enumeration of possible values. But if I enumerate, I cannot
> overload operations.
> What have I missed?

You can make an enumeration of structs:

struct S
{
  int i;
}

enum E
{
  Something = S(1),
  SomethingElse = S(2)
}