• Martin (22/22) Mar 23 2013 module main;
• Andrej Mitrovic (3/4) Mar 23 2013 Try:
• Martin (3/7) Mar 23 2013 That actually works, thanks. I thought tuples were supposed be
• Philippe Sigaud (31/42) Mar 23 2013 They are, I think it's a bug.
• Martin (2/50) Mar 23 2013 I see, thanks a lot

"Martin" <martinbbjerregaard gmail.com> writes:

module main;

struct TestStruct
{
     int a;
     int b;
     int c;
}

template getSomeMember(T)
{

     enum allMembers = __traits(allMembers, T);
     enum getSomeMember = allMembers[0];

}

void main(string[] args)
{

     enum someMember = getSomeMember!TestStruct;

}

Gives me the following erorrs:
main.d(13): Error: variable _allMembers_field_0 cannot be read at 
compile time
main.d(21): Error: template instance 
main.getSomeMember!(TestStruct) error instantiating

Running dmd 2.062

"Andrej Mitrovic" <andrej.mitrovich gmail.com> writes:

On Saturday, 23 March 2013 at 10:46:11 UTC, Martin wrote:
     enum allMembers = __traits(allMembers, T);

Try:
      enum allMembers = [__traits(allMembers, T)];

"Martin" <martinbbjerregaard gmail.com> writes:

On Saturday, 23 March 2013 at 11:55:37 UTC, Andrej Mitrovic wrote:
 On Saturday, 23 March 2013 at 10:46:11 UTC, Martin wrote:
    enum allMembers = __traits(allMembers, T);

 Try:
      enum allMembers = [__traits(allMembers, T)];

That actually works, thanks. I thought tuples were supposed be 
indexable though

Philippe Sigaud <philippe.sigaud gmail.com> writes:

On Sat, Mar 23, 2013 at 12:57 PM, Martin <martinbbjerregaard gmail.com> wrote:
 On Saturday, 23 March 2013 at 11:55:37 UTC, Andrej Mitrovic wrote:
 On Saturday, 23 March 2013 at 10:46:11 UTC, Martin wrote:
    enum allMembers = __traits(allMembers, T);


 Try:
      enum allMembers = [__traits(allMembers, T)];


 That actually works, thanks. I thought tuples were supposed be indexable
 though

They are, I think it's a bug.

If the alias grammar was more open, we could do:

alias allMembers = __traits(allMembers, T);

but since __traits are not accepted as an alias target, we must use a
wrapping template as a workaround:

import std.stdio;

struct TestStruct
{
    int a;
    int b;
    int c;
}

/// Just to hide __traits:
template Alias(aliases...)
{
    alias Alias = aliases;
}

template getSomeMember(T)
{

    alias members = Alias!(__traits(allMembers, T));

    // now members is a tuple of members
    // perfectly indexable & slicable
    enum getSomeMember = allMembers[0];

}

void main(string[] args)
{
    enum someMember = getSomeMember!TestStruct;
    writeln(typeof(someMember).stringof);
    writeln(someMember);
}

"Martin" <martinbbjerregaard gmail.com> writes:

On Saturday, 23 March 2013 at 12:12:30 UTC, Philippe Sigaud wrote:
 On Sat, Mar 23, 2013 at 12:57 PM, Martin 
 <martinbbjerregaard gmail.com> wrote:
 On Saturday, 23 March 2013 at 11:55:37 UTC, Andrej Mitrovic 
 wrote:
 On Saturday, 23 March 2013 at 10:46:11 UTC, Martin wrote:
    enum allMembers = __traits(allMembers, T);


 Try:
      enum allMembers = [__traits(allMembers, T)];


 That actually works, thanks. I thought tuples were supposed be 
 indexable
 though

 They are, I think it's a bug.

 If the alias grammar was more open, we could do:

 alias allMembers = __traits(allMembers, T);

 but since __traits are not accepted as an alias target, we must 
 use a
 wrapping template as a workaround:

 import std.stdio;

 struct TestStruct
 {
     int a;
     int b;
     int c;
 }

 /// Just to hide __traits:
 template Alias(aliases...)
 {
     alias Alias = aliases;
 }

 template getSomeMember(T)
 {

     alias members = Alias!(__traits(allMembers, T));

     // now members is a tuple of members
     // perfectly indexable & slicable
     enum getSomeMember = allMembers[0];

 }

 void main(string[] args)
 {
     enum someMember = getSomeMember!TestStruct;
     writeln(typeof(someMember).stringof);
     writeln(someMember);
 }

I see, thanks a lot