[Issue 24540] Add order/index to enum member to return its position

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24540

Nick Treleaven <nick at geany.org> changed:

           What    |Removed                     |Added
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                 CC|                            |nick at geany.org

--- Comment #2 from Nick Treleaven <nick at geany.org> ---
(In reply to apham from comment #0)
>   void set(Foo e)
>   {
>      v |= 1 << e.order;
>   }
>   
>   bool isSet(Foo e)
>   {
>     return (v & (1 << e.order)) != 0;
>   }

It's not possible to take a runtime enum value and produce its index in an enum
without some runtime overhead.

Another issue is that `e.order` is already valid code, meaning call `order(e)`.

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