bug in typeof or wrong enum specs?

[Jacob Carlborg]

On 2013-08-29 01:28, captaindet wrote:
> a recent discussion (
> http://forum.dlang.org/thread/kvje4r$1tff$1@digitalmars.com ) about the
> official enum dox ( http://dlang.org/enum.html ) was not conclusive whether
>
>      enum IDENTIFIER;
>
> is officially allowed/supported. jacob pointed out that it has an
> important use case in that it can serve as UDA. as UDAs are fairly new,
> this cannot be the reason why this syntax was allowed in the first place
> though, *if* it is allowed.

No, but now it's a useful use case.

> also, it might be used in meta stuff similar
> to "#define IDENTIFIER" in C - playing with this idea i run into this
> issue...
>
> while much code behaves with such an empty enum declaration,
>
>      writeln( __traits(compiles, IDENTIFIER) );    // true
>      writeln( is( IDENTIFIER == enum ) );            // true
>
> typeof() is not happy at all (DMD 2.063.2):
>
>      writeln( typeof(IDENTIFIER).stringof );
>      // Error: argument IDENTIFIER to typeof is not an expression
>
> typeof() expects an expression and a bare identifier is a
> "PrimaryExpression" ( http://dlang.org/expression.html#PrimaryExpression
> ) and hence a valid argument.
>
> either the empty enum declaration is not allowed (and should be removed
> from the dox and throw a compilation error) or there is a bug in typeof().

No, I previously misread your post.

enum foo;

The above declares a type, with the name "foo".

enum bar = 1;

Declares a manifest constant, short for:

enum int bar = 1;

The type is "int", the name of the constant is "bar".

typeof(bar); // ok, "bar" is not a type
typeof(int); // error, "int" is a type
typeof(foo); // error, "foo" is a type

Although I do think that typeof(type) should work and just return "type".

-- 
/Jacob Carlborg