ah yes, in chromium (and v8) we compile without RTTI, so we can't rely on
dynamic_cast. But yes, you can store a AnyBase* in the internal field and
then use a huge type switch to figure out the actual class.

Note that you still need a function that knows about all types you possible
have in your system (the typeswitch)..

On Fri, Feb 5, 2016 at 1:53 PM Zac Hansen <[email protected]> wrote:

> I think I did find it in WrapperTypeInfo.h.   And while I don't understand
> exactly how it works, I'm guessing it requires each class that contains a
> static WrapperTypeInfo to configure it in such a way that it can retrieve
> information like what derived classes are and such?
>
> I'm trying to write something that can work with arbitrary classes.. my
> current solution is to allow users to make an explicit list if which
> classes can be substituted in when a certain type is wanted.   It uses
> sfinae to make sure the specified types are derived types.
>
> Basically wrap_class_for_js<MyClass>().add_compatible_types<MyClassChild,
> MyClassGrandChild>();
>
> so when you say "some_function(new MyClassChild())" in javascript, my
> callback says "Is the GetInternalField of the v8::Object a MyClass?   No?
> Then let me try the compatible types.   Is it a MyClassChild?  Yes.  Ok,
> send the pointer in".   If it makes it to the end of the compatible type
> list without a match, it throws an exception (which is wrapped in a
> isoalte->ThrowException() before control returns to V8).
>
> The thing I put int the InternalField v8::External is actually an
> "AnyBase*" which is a base class of all Any<T> objects.. so I can use
> dynamic_cast to do the testing of whether the type is a desired type or not.
>
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