How to port C++ std::is_reference<T> to D ?

[wjoe]

On Wednesday, 6 May 2020 at 16:01:37 UTC, Paul Backus wrote:
> On Wednesday, 6 May 2020 at 09:40:47 UTC, wjoe wrote:
>> yes, I did read the spec. I read the language spec on traits 
>> as well as std.traits docs as well as searching the internet 
>> for a solution since day before yesterday. But I couldn't 
>> bring it together because
>>
>>   } else static if (__traits(isRef, T)) {
>>
>> compiles, but e.g.
>>
>>    assert (modifier!(ref int) == "[out] ");
>>
>> doesn't.
>> Anyways, thanks for your reply.
>
> D doesn't have reference *types*, it only has reference 
> *parameters*. Here's an example:
>
> void fun(ref int r, int v) {
>     static assert(is(typeof(r) == int)); // note: not `ref int`
>     static assert(is(typeof(r) == typeof(v))); // `ref` makes 
> no difference to type
>
>     static assert(__traits(isRef, r)); // note: not 
> `__traits(isRef, typeof(r))`
>     static assert(!__traits(isRef, v));
> }

Hello Paul, thanks for the explanation. This is quite the dilemma 
then. What this guy does in his library is he builds a static 
array at compile time and populates it with const and ref type 
names.