Greetings All

Can you help me with this code? I could not find any traits or other way to get me outer object of a given inner object. As for the context, I am fiddling with D trying to write a (domain specific) generic baseclass library. InnerBase is part of the library I write and the end user would be coding Outer and Inner classes. I do not want to force him to write getOuter kind of function. I would prefer not to ask him to add a mixin as well.

Is that possible, or is forcing the user to add a mixin the only way out?

Regards
- Cherry

////////////////////////////////////////////////////

class InnerBase{}
class Outer {
  class Inner: InnerBase {}
}
void main() {
  Outer outer = new Outer;
  auto inner = outer.new Outer.Inner();
  foo(inner);
}
void foo(T)(T t) {
  // somehow access inner.outer -- inner -> this.outer
  // Can not change Inner class to introduce getOuter functionality
  // I have access to InnerBase though and can add code there
}

How about having traits like hasOuter and getOuter (analogous to hasMember and getMember)?

I can give it a shot to add these traits to D compiler. But would such a pull request be accepted? I mean of course the code in the pull-request has to meet review expectations, but would such a PR be accepted from required feature perspective?

On 2016-08-30 04:43, Cherry wrote:
> Greetings All
>
> Can you help me with this code? I could not find any traits or other way
> to get me outer object of a given inner object.

Use the ".outer" property [1].

[1] http://dlang.org/spec/class.html#nested

-- 
/Jacob Carlborg

On Tuesday, 30 August 2016 at 02:43:16 UTC, Cherry wrote:

> Can you help me with this code?

class InnerBase { int a = 1; }
class Outer {
    int b = 2;
    class Inner: InnerBase { int c = 3; }
}

void main() {
    Outer outer = new Outer;
    auto inner = outer.new Outer.Inner();
    foo(inner);
}

void foo (T) (T t) {
    import std.stdio : writeln;
    writeln(t.a);           // prints 1
    writeln(t.outer.b);     // prints 2
    writeln(t.c);           // prints 3
}

dmd v2.071.2-b2

This should be posted in Learn at http://forum.dlang.org/group/learn