On 11/29/17 4:46 PM, Timon Gehr wrote:
On 29.11.2017 20:49, Steven Schveighoffer wrote:
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.
Well, I think the case of UDAs on parameters is closer to:
struct S{
@("a") int x1;
@("b") int x2;
}
The attributes on x1 and x2 are indeed part of the type S, even if the
attributes on S itself are not.
Right, but unlike functions, you can't make another "overload" of a struct.
If we go with "UDAs on parameters are not part of the function type",
how to you get the UDAs of the parameters of some function?
Looking at std.traits, it looks like we use this mechanism to get
everything:
int func(int param1)
static if(is(typeof(func) F == __parameters))
{
static assert(is(typeof(F[0]) == int));
static assert(__traits(identifier, F[0]) == "param1");
}
This is how vibe.d associates the function-level attributes with the
name of the parameter.
It wouldn't be a giant leap to make this work with attributes as well.
-Steve
