[webkit-dev] JS: Getter/Setter callbacks at Property level

[Brian Barnes]

In SpiderMonkey, you can create an object, and that object has a 
callback to a getter or a setter in C.  You get the name, look it up, 
return or set a value.  Nitro has that same functionality.

On SpiderMonkey, though, when creating a property, you can also do this:

JS_DefineProperty(context,object,name,value,getter,setter,flags);

Where "getter" and "setter" are direct calls for the property, for only 
that property.  There's no lookup logic in my code.

So, in pseudo code, at object level, we'd have a single getter:

void getMyObjectValues(.... name ...)
{
   if (name == 'red') return(red)
   if (name == 'green') return(green)
   if (name == 'blue') return(blue)
}

And property level, we'd have 3 getters:

void getMyObjectRed(...)
{
  return(red);
}

void getMyObjectGreen(...)
{
  return(green);
}

void getMyObjectBlue(...)
{
  return(blue);
}

[>] Brian

Geoffrey Garen wrote:
> Hi Brian.
>
> I don't understand the distinction you're drawing between "the 
> property level" and "the object level". Can you explain what those 
> mean and give an example of each?
>
> Thanks,
> Geoff
>
> On Jul 20, 2009, at 9:14 AM, Brian Barnes wrote:
>
>> I was getting ready to try the first move from SpiderMonkey to Nitro, 
>> and ran into a large problem.  Right now, all my getters and setters 
>> are at the property level.  In the documentation I have, Nitro only 
>> seems to put them at the object level.  This would force a huge 
>> refactoring of my code (which I'm willing to do if I have to, I would 
>> just like to avoid it as I have hundred or so objects.)
>>
>> Is my documentation old, did I miss something, or am I stuck?  If I'm 
>> stuck, is there any call to have this put into Nitro at some time in 
>> the future?
>>
>> [>] Brian
>>
>>
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>
>