uda pattern foo and foo(val)

[Steven Schveighoffer]

On Wednesday, 23 September 2020 at 01:57:08 UTC, Adam D. Ruppe 
wrote:
> On Wednesday, 23 September 2020 at 01:45:46 UTC, Steven 
> Schveighoffer wrote:
>> @foo int z; // Error: cannot interpret foo(T)(T val) at 
>> compile time
>
> Where do you get that error? Is it from phobos' thing? cuz I 
> copy/pasted your code and it compiled.
>
> You can also just use a struct as the uda if your detection 
> function checks for both the type and a value of the type, so 
> it really depends on which search method you using.

I just said pragma(msg, __traits(getAttributes, z))

Well actually the thing I tried is slightly different. As usual I 
dumbed it down to post here (maybe was a bad idea).

A struct won’t work because the foo(val) form needs to hold any 
type and ifti doesn’t work on constructors.

-Steve