Thank you very much for the info, Matthias. Although, I have to admit
I haven't been able to get it working properly, yet.
Is there a way to pass arguments when creating new instances using
this method? I'm running in to issues where I define the constructor
for a function:
... = FunctionTemplate::New(constructor_callback);
Handle<Value> constructor_callback(const Arguments& args[])
{
if (args.Length() != 3)
{
return throwArgLengthException(3);
}
}
------
Now, when I call NewInstance() on the ObjectTemplate, I guess it calls
the callback function. That in turn complains that the object needs 3
arguments (as it should).
On Jan 22, 3:53 pm, Matthias Ernst <[email protected]> wrote:
> Create a static ObjectTemplate for "Points" and set accessors and
> functions on it.
> From the function, you return an pointTemplate->NewInstance().
>
> Here's an example I have handy for "Prices", the object being backed
> by a C++ "Price" object:
>
> +Handle<ObjectTemplate> PriceTemplate() {
> + Handle<ObjectTemplate> result = ObjectTemplate::New();
> + result->SetAccessor(String::New("amount"), GetPriceAmount);
> + result->SetAccessor(String::New("currency"), GetPriceCurrency);
> +
> + result->SetInternalFieldCount(1);
> + return Persistent<ObjectTemplate>::New(result);
> +}
> +
> +Handle<Object> WrapPrice(const Price *p) {
> + static Handle<ObjectTemplate> price_template = PriceTemplate();
> +
> + Handle<Object> result = price_template->NewInstance();
> + result->SetInternalField(0, External::New(const_cast<Price *>(p)));
> + return result;
> +}
>
> On Thu, Jan 22, 2009 at 5:43 PM, vlad <[email protected]> wrote:
>
> > Also, I've been looking over the Google Chrome source code, but can't
> > find examples of this. If anyone knows where I can find example under
> > the Chrome source tree, please speak up.
>
> > On Jan 22, 10:56 am, vlad <[email protected]> wrote:
> >> I am still having problems returning an object from a getter, or from
> >> any function from that matter.
>
> >> I can't just call the same constructor callback that I use to create
> >> the object, because v8::Arguments constructor is private. And it
> >> doesn't seem like proper approach either.
> >> I also tried the solution that luiskarlos sudgested, but that's not it
> >> either. Some is returned, but there's no way to tell V8 that the
> >> return object is of X type -- it always seems to believe that the
> >> returned object is of the type doing the returning. Plus, if this were
> >> the way to return an object instance, then it would mean that you have
> >> to REdeclare destructor callbacks for those object instances.
> >> I would have though that FunctionTemplate would have some method of
> >> instantiating an instance, but I don't see any methods of doing this.
>
> >> Can someone please shine some light on this?
>
> >> How can one return an object instance of type X from a function or
> >> method?
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