• sigod (14/14) May 07 2014 void registerAll(alias module_)()
• Philippe Sigaud via Digitalmars-d-learn (18/22) May 08 2014 It's a syntax limitation for alias. That bites us from time to time.
• sigod (4/11) May 08 2014 Oh, thank you.

"sigod" <sigod.mail gmail.com> writes:

void registerAll(alias module_)()
{
      foreach (m; __traits(derivedMembers, module_)) {
          regInner!(__traits(getMember, module_, m)); // compiles

          alias a = __traits(getMember, module_, m); // fails
          //Error: basic type expected, not __traits
          //Error: semicolon expected to close alias declaration
      }
}

void regInner(alias T)()
{
      // ...
}

Is this a bug or I've missed something?

Philippe Sigaud via Digitalmars-d-learn writes:

          alias a = __traits(getMember, module_, m); // fails
          //Error: basic type expected, not __traits
          //Error: semicolon expected to close alias declaration

 Is this a bug or I've missed something?

It's a syntax limitation for alias. That bites us from time to time.
A workaround is to wrap it into another template, to 'hide' __traits.

Like this:

alias Alias(alias a) = a; // A bit circular, I know.

void registerAll(alias module_)()
{
     foreach (m; __traits(derivedMembers, module_)) {
         regInner!(__traits(getMember, module_, m));

         alias a = Alias!(__traits(getMember, module_, m)); // compiles
     }
}

void regInner(alias T)()
{
     // ...
}

void main(){}


I think there is bug report / enhancement for this. I find it a bit
annoying, since aliasing a __traits expression is quite common.

"sigod" <sigod.mail gmail.com> writes:

On Thursday, 8 May 2014 at 07:33:34 UTC, Philippe Sigaud via 
Digitalmars-d-learn wrote:
 A workaround is to wrap it into another template, to 'hide' 
 __traits.

 Like this:

 alias Alias(alias a) = a; // A bit circular, I know.

Oh, thank you.

 I think there is bug report / enhancement for this. I find it a 
 bit
 annoying, since aliasing a __traits expression is quite common.

This one https://issues.dlang.org/show_bug.cgi?id=7804, I believe.