Lazy evaluation of enum members

[Jonathan M Davis]

On Friday, September 20, 2013 09:10:10 Walter Bright wrote:
> Enum member forward references now work:
> 
> void main()
> {
>      enum E
>      {
>          A = B,
>          E = D + 7,
>          B = 3,
>          C,
>          D,
>      }
> 
>      assert(E.A == 3);
>      assert(E.B == 3);
>      assert(E.C == 4);
>      assert(E.D == 5);
>      assert(E.E == 12);
>      assert(E.max == 12);
> }
> 
> https://github.com/D-Programming-Language/dmd/pull/2568
> 
> Once this is pulled, I intend to extend it so that enum members for imports
> are not semantically evaluated at all unless they are used. This is a first
> step to making all semantic evaluation of imports lazy, which should give
> us a big boost in compilation speed, as well as do a much better job at
> handling forward references.
> 
> I've been meaning to do this for some time, starting with enums because they
> are the easiest.

But if you make the compiler too fast, then this XKCD won't be true anymore! 
;)

http://xkcd.com/303/

- Jonathan M Davis