• John Colvin (7/7) Oct 16 2013 It seems that __traits(getAttributes, T) returns an empty tuple
• Dicebot (9/16) Oct 16 2013 I think this gets re-written like this:
• Dicebot (3/3) Oct 16 2013 (quick experiments show that one can't attached UDA to template
• Max Samukha (6/9) Oct 16 2013 It is understandable why the attribute is transferred to the
• Max Samukha (2/4) Oct 16 2013 Impossible, ignore
• Max Samukha (7/12) Oct 16 2013 @(1)
• Dicebot (10/16) Oct 16 2013 @(1)
• Max Samukha (4/24) Oct 16 2013 That sucks. Then, getAttributes (and other traits dealing with
• Jacob Carlborg (5/8) Oct 16 2013 Currenrly one need to call __traits(getOverloads) and then iterate of

"John Colvin" <john.loughran.colvin gmail.com> writes:

It seems that __traits(getAttributes, T) returns an empty tuple 
for any template (or template function) T, no matter what UDAs T 
has been given.

Am I doing something wrong?

 (1) void foo(T)(){}

pragma(msg, __traits(getAttributes, foo)); // tuple()
pragma(msg, __traits(getAttributes, foo!int)); // tuple(1)

"Dicebot" <public dicebot.lv> writes:

On Wednesday, 16 October 2013 at 12:26:34 UTC, John Colvin wrote:
 It seems that __traits(getAttributes, T) returns an empty tuple 
 for any template (or template function) T, no matter what UDAs 
 T has been given.

 Am I doing something wrong?

  (1) void foo(T)(){}

 pragma(msg, __traits(getAttributes, foo)); // tuple()
 pragma(msg, __traits(getAttributes, foo!int)); // tuple(1)

I think this gets re-written like this:

template foo(T)
{
      (1) void foo() {}
}

..which does explain the observed behavior. As a workaround you 
can define some default guard value of T and assert inside foo() 
call if it is actually ever used.

"Dicebot" <public dicebot.lv> writes:

(quick experiments show that one can't attached UDA to template 
symbol itself by any means - weird limitation, don't know the 
rationale behind this)

"Max Samukha" <maxsamukha gmail.com> writes:

On Wednesday, 16 October 2013 at 12:37:23 UTC, Dicebot wrote:
 (quick experiments show that one can't attached UDA to template 
 symbol itself by any means - weird limitation, don't know the 
 rationale behind this)

It is understandable why the attribute is transferred to the 
instantiation of the function template, though I'd rather have 
the same set of attributes on both the template and its 
instantiations in this case. There is no reason why attributes 
cannot be applied to templates themselves. I think that's a bug.

"Max Samukha" <maxsamukha gmail.com> writes:

On Wednesday, 16 October 2013 at 13:12:39 UTC, Max Samukha wrote:
 I'd rather have the same set of attributes on both the template 
 and its instantiations

Impossible, ignore

"Max Samukha" <maxsamukha gmail.com> writes:

On Wednesday, 16 October 2013 at 13:14:31 UTC, Max Samukha wrote:
 On Wednesday, 16 October 2013 at 13:12:39 UTC, Max Samukha 
 wrote:
 I'd rather have the same set of attributes on both the 
 template and its instantiations

 Impossible, ignore

 (1)
template Foo(T : int) {}

 (2)
template Foo(T : short) {}

__traits(getAttributes, Foo) == ?

The current semantics seems quite reasonable.

"Dicebot" <public dicebot.lv> writes:

On Wednesday, 16 October 2013 at 13:24:59 UTC, Max Samukha wrote:
  (1)
 template Foo(T : int) {}

  (2)
 template Foo(T : short) {}

 __traits(getAttributes, Foo) == ?

 The current semantics seems quite reasonable.

 (1)
void foo(int) {}

 (2)
void foo(double) {}

pragma(msg, __traits(getAttributes, foo));

void main() {}

// Compilation output:
//
// tuple(1)

"Max Samukha" <maxsamukha gmail.com> writes:

On Wednesday, 16 October 2013 at 13:38:44 UTC, Dicebot wrote:
 On Wednesday, 16 October 2013 at 13:24:59 UTC, Max Samukha 
 wrote:
  (1)
 template Foo(T : int) {}

  (2)
 template Foo(T : short) {}

 __traits(getAttributes, Foo) == ?

 The current semantics seems quite reasonable.

  (1)
 void foo(int) {}

  (2)
 void foo(double) {}

 pragma(msg, __traits(getAttributes, foo));

 void main() {}

 // Compilation output:
 //
 // tuple(1)

That sucks. Then, getAttributes (and other traits dealing with 
overload sets) should return an empty set, a union or accept a 
pattern to match against the members of the overload set.

Jacob Carlborg <doob me.com> writes:

On 2013-10-16 16:05, Max Samukha wrote:

 That sucks. Then, getAttributes (and other traits dealing with overload
 sets) should return an empty set, a union or accept a pattern to match
 against the members of the overload set.

Currenrly one need to call __traits(getOverloads) and then iterate of 
the result and call __traits(getAttributes) on each item.

-- 
/Jacob Carlborg