Custom attributes (again)

[Piotr Szturmaj]

Andrei Alexandrescu wrote:
> On 4/6/12 1:47 AM, Walter Bright wrote:
>> __traits(hasAttribute, x, foo)
>>
>> would return true, and:
>>
>> __traits(getAttribute, x, foo)
>>
>> would return the expression (bar+1). The expression would be
>> compile-time only, evaluated at the point of declaration.
>
> You also need means to enumerate attributes.

Minimalistically getAttribute*s* should be enough:

__traits(getAttributes, x)

would return all attributes of x.

The rest can be implemented as library templates in std.traits.