Hi Bradley,
thanks for the reply, but maybe I have not expressed clearly: I don't want
to *convert* my c++ classes to javascript.
Instead, I create a *custom module* with *node::ObjectWrap*
class AnimalWrap : public node::ObjectWrap {
public:
static Handle<Value> sound(const Arguments &args);
static Persistent<FunctionTemplate> constructor_tpl;
protected:
int typeId;
}
Now, the Dog, that inherits from Animal should also have a Wrapper.
*Option (1):*
class DogWrap : public AnimalWrap, public Dog {
protected:
bool houseTrained;
}
*Option (2):*
template <class A> class AnimalWrap {...};
template <> AnimalWrap<Dog> {
protected:
bool houseTrained;
};
With multiple inheritance (1), I would not know how to check if Dog is a
Dog but not any other animal, since "constructor_tpl" would not be
specialized for Dog. Also, I cannot overwrite sound() in Dog, because it is
static and would not be virtually evaluated to Dog::sound() if called from
other functions in Animal::*.
With template specialization (2), all the static code, like sound() would
have to be reimplemented in AnimalWrap<Dog>.
tl;rt
Wrapping one class with ObjectWrap is perfectly fine, but how to wrap an
existing C++ class hierarchy?
Am Montag, 10. Dezember 2012 20:40:11 UTC+5:30 schrieb Bradley Meck:
>
> Encapsulated bindings.
>
> Make all bindings available w/ some naming convention for the namespaces.
> Have a constructor function per type
> * Have Animal.prototype be the members of Animal::
> * Have Dog.prototype be the members of Dog::
> Attach the static functions to constructor functions
>
> Add sugar if you need a destructor / be sure to call the parent function
> constructor inside of subclasses:
>
> function Dog() {
> Animal.call(this);
> return this;
> }
>
> Checking for instance type:
>
> // since people should be using our constructor that maps to an instance
> via ObjectWrap....
> if (spot instanceof Dog) { ... }
>
> When using virtual static functions [ :-( ] you can add them to the
> constructor (this pattern is highly discouraged generally):
>
> function Dog() { ... }
> var DogStatics = Object.create(AnimalStatics)
> ...
> Object.keys(DogStatics).forEach(function (key) {
> Dog[key] = DogStatics[key]
> });
>
> In general however, directly mapping C++ onto JS will meet with some
> confusion as the mentalities of the languages are vast, so be sure that
> this is what you want to do.
>
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