Hi,

I was able to reach all the fields in a subclass using foreach and BaseClassesTuple, but is there a way to do this using functional programming primitives, but in compile time for tuples?

private template FieldNameTuple2(T) {
  enum FieldNameTuple2 = BaseClassesTuple!T.map!(S => FieldNameTuple!S).join;
}

This is obviously wrong, but is there a way to do it?

I've searched for FieldNameTuple and BaseClassesTuple, but without luck. It's weird because it seems like a common thing to do.

Thanks in advance!

On Tuesday, 19 May 2020 at 23:15:45 UTC, realhet wrote:
> Hi,
>
> I was able to reach all the fields in a subclass using foreach and BaseClassesTuple, but is there a way to do this using functional programming primitives, but in compile time for tuples?
>
> private template FieldNameTuple2(T) {
>   enum FieldNameTuple2 = BaseClassesTuple!T.map!(S => FieldNameTuple!S).join;
> }
>
> This is obviously wrong, but is there a way to do it?
>
> I've searched for FieldNameTuple and BaseClassesTuple, but without luck. It's weird because it seems like a common thing to do.
>
> Thanks in advance!

I think what you want is `std.meta.staticMap`. Something like this:

alias FieldNameTuple2(T) = staticMap!(FieldNameTuple, BaseClassesTuple!T);

On Wednesday, 20 May 2020 at 01:18:24 UTC, Paul Backus wrote:
> On Tuesday, 19 May 2020 at 23:15:45 UTC, realhet wrote:
> I think what you want is `std.meta.staticMap`. Something like this:
>
> alias FieldNameTuple2(T) = staticMap!(FieldNameTuple, BaseClassesTuple!T);

class A { int a, a1; }
class B : A { int b; }
class C : B { int c, c1; }

alias AllClasses(T) = Reverse!(AliasSeq!(T, BaseClassesTuple!T[0..$-1]));
alias AllFieldNames(T) = staticMap!(FieldNameTuple, AllClasses!T);

void main(){
  static foreach(T; "ABC") mixin("AllFieldNames!"~T~".stringof.writeln;");
}

That statticMap unlike the normal map, it also joins the AliasSeq at the end. Just what I needed.

Thank You!

On Wednesday, 20 May 2020 at 09:03:51 UTC, realhet wrote:
> On Wednesday, 20 May 2020 at 01:18:24 UTC, Paul Backus wrote:
>> On Tuesday, 19 May 2020 at 23:15:45 UTC, realhet wrote:

With this mod it also works with structs:

template AllClasses(T){
    static if(is(T == class))
        alias AllClasses = Reverse!(AliasSeq!(T, BaseClassesTuple!T[0..$-1]));
    else
        alias AllClasses = T;
}

On 5/20/20 12:03 PM, realhet wrote:
> On Wednesday, 20 May 2020 at 01:18:24 UTC, Paul Backus wrote:
>> On Tuesday, 19 May 2020 at 23:15:45 UTC, realhet wrote:
>> I think what you want is `std.meta.staticMap`. Something like this:
>>
>> alias FieldNameTuple2(T) = staticMap!(FieldNameTuple, BaseClassesTuple!T);
> 
> class A { int a, a1; }
> class B : A { int b; }
> class C : B { int c, c1; }
> 
> alias AllClasses(T) = Reverse!(AliasSeq!(T, BaseClassesTuple!T[0..$-1]));
> alias AllFieldNames(T) = staticMap!(FieldNameTuple, AllClasses!T);
> 
> void main(){
>    static foreach(T; "ABC") mixin("AllFieldNames!"~T~".stringof.writeln;");
> }
> 
> That statticMap unlike the normal map, it also joins the AliasSeq at the end. Just what I needed.
> 
> Thank You!

Just in case - you can avoid mixin using:
```D
  static foreach(T; AliasSeq!(A, B, C))
      AllFieldNames!T.stringof.writeln;
```

https://run.dlang.io/is/Q6omgL