• kenji hara (11/11) May 09 2011 I have tried to implement multiple inheritance in D.
• Andrei Alexandrescu (10/21) May 09 2011 This is very interesting. I don't understand the example though (some is...
• kenji hara (13/15) May 10 2011 I posted 'Issue 5973 - alias this is not considered with superclass
• Jacob Carlborg (4/15) May 09 2011 Why not emulate it with interfaces and template mixins?
• kenji hara (3/4) May 10 2011 Interfaces? I don't understand what you mean.
• Jacob Carlborg (16/20) May 10 2011 interface Super {

kenji hara <k.hara.pg gmail.com> writes:

I have tried to implement multiple inheritance in D.

My first idea is binary inheritance tree with using alias this, but
current dmd doesn't look alias this on superclasses.
So I have tried to fix this behavior.
-> https://github.com/9rnsr/dmd/tree/MultiInheritPatch

Result:
-> http://ideone.com/iD4JE

Some issues:
- Calling constructors of superclasses syntax.
- Object layout (share __monitor object? reduce overhead?)

Do you think?

Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:

On 5/9/11 12:43 PM, kenji hara wrote:
 I have tried to implement multiple inheritance in D.

 My first idea is binary inheritance tree with using alias this, but
 current dmd doesn't look alias this on superclasses.
 So I have tried to fix this behavior.
 ->  https://github.com/9rnsr/dmd/tree/MultiInheritPatch

 Result:
 ->  http://ideone.com/iD4JE

 Some issues:
 - Calling constructors of superclasses syntax.
 - Object layout (share __monitor object? reduce overhead?)

 Do you think?

This is very interesting. I don't understand the example though (some is 
commented out, some is in, and I'm unclear on what didn't use to work 
and what works). Also I can't find the important commits in your branch, 
so it may be best to organize those as one pull request for the dmd 
mainline.

Could you please provide more detail on what you fixed and what the 
resulting context is?


Thanks,

Andrei

kenji hara <k.hara.pg gmail.com> writes:

Thanks for your comment.

 Could you please provide more detail on what you fixed and what the
 resulting context is?

I posted 'Issue 5973 - alias this is not considered with superclass
lookup' for dmd issue.
http://d.puremagic.com/issues/show_bug.cgi?id=5973
The issue is that dmd does not consider alias this in super classes on
member lookup.

More clean code: https://github.com/9rnsr/scrap/blob/master/multiInherit.d
New feature:
- Support class that have explicit constructor.
  See X.this code with -version=ExplicitCtor.

May not support:
- Diamond inheritance

Kenji Hara

Jacob Carlborg <doob me.com> writes:

On 2011-05-09 19:43, kenji hara wrote:
 I have tried to implement multiple inheritance in D.

 My first idea is binary inheritance tree with using alias this, but
 current dmd doesn't look alias this on superclasses.
 So I have tried to fix this behavior.
 ->  https://github.com/9rnsr/dmd/tree/MultiInheritPatch

 Result:
 ->  http://ideone.com/iD4JE

 Some issues:
 - Calling constructors of superclasses syntax.
 - Object layout (share __monitor object? reduce overhead?)

 Do you think?

Why not emulate it with interfaces and template mixins?

-- 
/Jacob Carlborg

kenji hara <k.hara.pg gmail.com> writes:

 Why not emulate it with interfaces and template mixins?

Interfaces? I don't understand what you mean.
So please give me a example code.

Kenji Hara

Jacob Carlborg <doob me.com> writes:

On 2011-05-10 10:14, kenji hara wrote:
 Why not emulate it with interfaces and template mixins?

 Interfaces? I don't understand what you mean.
 So please give me a example code.

 Kenji Hara

interface Super {
     void foo ();
}

template SuperImpl {
     void foo () { /* do something */ }
}

class Sub : Super {
     mixin SuperImpl;

     void bar () { /* do something else */ }
}

This might not be the best solution, it won't work with existing class 
hierarchies. I've actually tried this now and it won't work, you cannot 
override the methods coming from the mixin.

-- 
/Jacob Carlborg