As far as I can tell, this code should compile:

class B       { int a; }
class D1 : B  { int b; }
class D2 : D1 { int c; }

template TupleOf(Classes...)
{
    static if(Classes.length > 1)
        alias TupleOf = AliasSeq!(Classes[0].tupleof, TupleOf!(Classes[1..$]));
    else static if(Classes.length == 1)
        alias TupleOf = AliasSeq!(Classes[0].tupleof);
    else
        alias TupleOf = AliasSeq!();
}

int main(string[] argv)
{
    alias allClasses = AliasSeq!(D2, BaseClassesTuple!D2);
    alias allFields = TupleOf!allClasses;
    return 0;
}


But I get this:

Error: template instance AliasSeq!(b, a) AliasSeq!(b, a) is nested in both D1 and B
Error: template instance main.TupleOf!(D1, B, Object) error instantiating
instantiated from here: TupleOf!(D2, D1, B, Object)

Any ideas?

  Thanks

On 9/29/17 11:39 PM, bitwise wrote:
> As far as I can tell, this code should compile:
> 
> class B       { int a; }
> class D1 : B  { int b; }
> class D2 : D1 { int c; }
> 
> template TupleOf(Classes...)
> {
>      static if(Classes.length > 1)
>          alias TupleOf = AliasSeq!(Classes[0].tupleof, TupleOf!(Classes[1..$]));
>      else static if(Classes.length == 1)
>          alias TupleOf = AliasSeq!(Classes[0].tupleof);
>      else
>          alias TupleOf = AliasSeq!();
> }
> 
> int main(string[] argv)
> {
>      alias allClasses = AliasSeq!(D2, BaseClassesTuple!D2);
>      alias allFields = TupleOf!allClasses;
>      return 0;
> }
> 
> 
> But I get this:
> 
> Error: template instance AliasSeq!(b, a) AliasSeq!(b, a) is nested in both D1 and B
> Error: template instance main.TupleOf!(D1, B, Object) error instantiating
> instantiated from here: TupleOf!(D2, D1, B, Object)
> 
> Any ideas?
> 
>    Thanks

I think the problem may be that derived classes' tupleof has some of the same variables as the base class?

I agree it should work, but I think if it did work, it may not be what you want. You would see a lot of repeats.

BTW, AliasSeq!(x.tupleof) is redundant, x.tupleof is already an AliasSeq.

-Steve

On Saturday, 30 September 2017 at 12:42:17 UTC, Steven Schveighoffer wrote:
>
> I think the problem may be that derived classes' tupleof has some of the same variables as the base class?
>
> I agree it should work, but I think if it did work, it may not be what you want. You would see a lot of repeats.

.tupleof doesn't return fields from base classes.

assert(D2.tupleof.stringof == "tuple(c)");

On Saturday, 30 September 2017 at 12:42:17 UTC, Steven Schveighoffer wrote:
> [...]

https://issues.dlang.org/show_bug.cgi?id=17870