Attributes on Enum Members: Call for use cases.

[Steven Schveighoffer]

On 11/29/17 2:01 PM, Timon Gehr wrote:

OK, now I get what you are saying. In the same vein, I tested applying 
attributes to functions themselves:

@("a") int fun() { return 0; }
pragma(msg, typeof(&fun)); // int function()

@("b") int gun() { return 1; }
pragma(msg, typeof(&gun)); // int function()

void main()
{
   auto f = &fun;
   f = &gun; // works
}

Given that, it seems attributes play no part in the type itself, they 
are just metadata in the compiler.

I would say:

> 
> struct attribute1{}
> struct attribute2{}
> 
> int foo(@attribute1 int x){ return x; }
> int bar(@attribute2 int y){ return y; }
> 
> pragma(msg, typeof(&foo)); // int function(@attribute1 int x)?

int function(int)

> pragam(msg, typeof(&bar)); // int function(@attribute2 int x)?

same

> 
> auto apply(F,A)(F fun,A arg){
>      pragma(msg, F); // ? (instantiations below)

same

>      return fun(arg);
> }
> 
> void main(){
>      apply(&foo,1); // one instantiation
>      apply(&bar,1); // second instantiation, or same instance?

same instance

> }
> 
> auto weird(){
>      int x;
>      void foo(@x int y){}
>      return &foo;
> }
> 
> pragma(msg, typeof(weird())); // ?

void delegate(int)

-Steve