Re: [boost] Reflection?

Subject: Re: [boost] Reflection?
From: Jeremy Pack (rostovpack_at_[hidden])
Date: 2008-11-01 10:47:47

I'm working on Boost.Reflection - see http://boost-extension.blogspot.com. I
gave a presentation on it at BoostCon this year.

Jeremy Pack

On Fri, Oct 31, 2008 at 9:20 PM, Jean-Louis Leroy <jl_at_[hidden]> wrote:

> Is runtime reflection going to be available in boost soon? The last I have
> found on the subject is
> http://lists.boost.org/Archives/boost/2007/08/126006.php but I see nothing
> in the sandbox nor the vault.
>
> I have toyed with an implementation myself. It supports member variables
> and functions, multiple and virtual inheritance and object creation.
>
> Here is what it looks like.
>
> First a small hierarchy:
>
>  class animal { /* ... */ };
>  class mammal : public virtual animal { /* ... */ };
>  class carnivore : public virtual animal{ /* ... */ };
>  class dog : public mammal, public carnivore{ /* ... */ };
>
> Reflection info is filled like this:
>
>  reflection_class<animal>::name("animal");
>  reflection_class<animal>::variable("age", &animal::age);
>  // etc
>
>  reflection_class<mammal>::name("mammal");
>  reflection_class<mammal>::base<animal>(virtual_);
>  // etc
>
>  reflection_class<carnivore>::name("carnivore");
>  reflection_class<carnivore>::base<animal>(virtual_);
>  // etc
>
>  reflection_class<dog>::name("dog");
>  reflection_class<dog>::base<mammal>();
>  reflection_class<dog>::base<carnivore>();
>  // a function
>  reflection_class<dog>::function("bark", &dog::bark);
>  // overloaded functions
>  reflection_class<dog>::function<string (dog::*)(void) const>("name",
> &dog::name);
>  reflection_class<dog>::function<void (dog::*)(const string&)>("name",
> &dog::name);
>  // constructor
>  reflection_class<dog>::constructor<void* (*)()>();
>  // etc
>
> And here how it's used:
>
>  animal* pa(new dog);
>
>  object o(downcast(pa)); // recover dynamic type
>
>  // access member variable inherited from virtual base `animal'
>  member_variable<int> dog_age(o, "age");
>  int age = o[dog_age];
>
>  // call member function
>  member_function<string (object::*)() const> dog_name(o, "name");
>  string name = o[dog_name]();
>
>  // create a dog using default ctor
>  object o("dog");
>
> Ok, there is a bit more to it (e.g. support macros, ambiguity detection,
> handling of shadowed members, overloaded ctors) but the important part is
> shown above. All in all it is a foundation upon which one can build
> multimethods, generic object processing (like Perl's data::Dumper),
> serialization, object-relational mapping and all sorts of nice tools.
>
> Does anybody see interest in this work?
>
> Jean-Louis
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