Is it possible to evaluate an enum's base type? Ideally something like:

enum somestrs : string { ... }
enum d = 0.0;
template EnumBaseType(E) if (is(E==enum)) { ... }
unittest {
   static assert( is(EnumBaseType!somestrs == string) );
   static assert( is(EnumBaseType!d : float) );
   static assert(!is(EnumBaseType!d == float) );
}

A template like this would make at least my life easier.

On 2013-04-17, 19:15, Janissary wrote:

> Is it possible to evaluate an enum's base type? Ideally something like:
>
> enum somestrs : string { ... }
> enum d = 0.0;
> template EnumBaseType(E) if (is(E==enum)) { ... }
> unittest {
>     static assert( is(EnumBaseType!somestrs == string) );
>     static assert( is(EnumBaseType!d : float) );
>     static assert(!is(EnumBaseType!d == float) );
> }
>
> A template like this would make at least my life easier.

Whenever you want to do weird stuff with types, std.traits[1] should
be your #1 stop. And quite correctly, std.traits.OriginalType[2] does
what you want:

  enum E : int { a }
  typedef E F;
  typedef const F G;
  static assert(is(OriginalType!G == const int));

[1]: http://dlang.org/phobos/std_traits
[2]: http://dlang.org/phobos/std_traits#.OriginalType
-- 
Simen

On Wednesday, 17 April 2013 at 18:56:43 UTC, Simen Kjaeraas wrote:
> On 2013-04-17, 19:15, Janissary wrote:
>
>> Is it possible to evaluate an enum's base type? Ideally something like:
>>
>> enum somestrs : string { ... }
>> enum d = 0.0;
>> template EnumBaseType(E) if (is(E==enum)) { ... }
>> unittest {
>>    static assert( is(EnumBaseType!somestrs == string) );
>>    static assert( is(EnumBaseType!d : float) );
>>    static assert(!is(EnumBaseType!d == float) );
>> }
>>
>> A template like this would make at least my life easier.
>
> Whenever you want to do weird stuff with types, std.traits[1] should
> be your #1 stop. And quite correctly, std.traits.OriginalType[2] does
> what you want:
>
>   enum E : int { a }
>   typedef E F;
>   typedef const F G;
>   static assert(is(OriginalType!G == const int));
>
> [1]: http://dlang.org/phobos/std_traits
> [2]: http://dlang.org/phobos/std_traits#.OriginalType

Thanks, that's just what I needed.