List of derived types?
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
Re: List of derived types?
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);
Re: List of derived types?
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?
Re: List of derived types?
d coder dlang.co...@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
Re: List of derived types?
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.
