• d coder (8/8) Dec 16 2010 Greetings
• Michal Minich (7/17) Dec 16 2010 you can iterate all modules to find base classes. see object_.d file to
• =?ISO-8859-1?Q?Pelle_M=E5nsson?= (2/10) Dec 16 2010 I'm curious, why do you need that?
• d coder (16/17) Dec 16 2010 It is a long story.
• Simen kjaeraas (26/32) Dec 16 2010 No.

d coder <dlang.coder gmail.com> writes:

Greetings

I need a way to know (using traits or other compile time constructs)
all the types derived from a given type.
Is it possible in D?

Is it possible to get a list of all the user-defined classes? I could
use that to filter out the classes that I need.

Regards
Cherry

Michal Minich <michal.minich gmail.com> writes:

V Thu, 16 Dec 2010 18:46:41 +0530, d coder wrote:

 Greetings
 
 I need a way to know (using traits or other compile time constructs) all
 the types derived from a given type. Is it possible in D?
 
 Is it possible to get a list of all the user-defined classes? I could
 use that to filter out the classes that I need.
 
 Regards
 Cherry

you can iterate all modules to find base classes. see object_.d file to 
see sturcture of TypeInfo_Class or ModuleInfo.

     foreach(m; ModuleInfo)
        foreach (c; m.localClasses)
            if (c.base !is null)
                writefln(c.base.name);

=?ISO-8859-1?Q?Pelle_M=E5nsson?= <pelle.mansson gmail.com> writes:

On 12/16/2010 02:16 PM, d coder wrote:
 Greetings

 I need a way to know (using traits or other compile time constructs)
 all the types derived from a given type.
 Is it possible in D?

 Is it possible to get a list of all the user-defined classes? I could
 use that to filter out the classes that I need.

 Regards
 Cherry

I'm curious, why do you need that?

d coder <dlang.coder gmail.com> writes:

 I'm curious, why do you need that?

It is a long story.

But basically I am creating a platform wherein the users would be
deriving classes from some base classes that I write as part of the
platform. And the users would often be deriving many such classes.

The end-users would often not be programmers and would know little D
(as you can see I am also learning D :-). I want to automate some code
generation for them and I hope to do that by creating wrapper classes
that would shadow the classes that the end-users have written. Since
the and users would be instantiating these classes only inside a
particular class scope, I wanted to create some code inside that class
scope. Right now I am forcing the end-users to insert some mixin for
every class that they code. I wanted to automate that process.

Hope what I said makes sense to you.

Regards
Cherry

Hope what I said makes sense.

"Simen kjaeraas" <simen.kjaras gmail.com> writes:

d coder <dlang.coder gmail.com> wrote:

 Greetings

 I need a way to know (using traits or other compile time constructs)
 all the types derived from a given type.
 Is it possible in D?

No.

 Is it possible to get a list of all the user-defined classes? I could
 use that to filter out the classes that I need.

No.


However, it is possible at run-time to iterate through all classes and
at that time compare them to the base class:

T[] getDerivedClasses( T )( ) if ( is( T == class ) ) {
     T[] result;
     foreach ( mod; ModuleInfo ) {
         foreach ( cls; mod.localClasses ) {
             if ( mod.name == "object" ) {
                 break;
                 }
             auto cls_base = cls;
             do {
                 if ( cls_base.name == T.classinfo.name ) {
                     if ( T tmp = cast(T)cls.create( ) ) {
                         result ~= tmp;
                     }
                 }
             } while ( ( cls_base = cls_base.base ) != Object.classinfo );
         }
     }
     return result;
}


-- 
Simen