On Wed, Oct 8, 2008 at 12:15 PM, Kris Zyp <[EMAIL PROTECTED]> wrote:
> Peter,
> I believe the primary purpose for this design is to preserve the
> correct |this| for setters. For example:
> p = {set a(value){ console.log(this.id) }, id: 1};
What is the above syntax with "set"? Is that a JavaScript-specific or
a Rhino-specific extension to the language?
Thanks,
Peter
> P = function(){};
> P.prototype = p;
> o = new P;
> o.id = 2;
> o.a = 3;
> This should log the value 2 (not 1), and so basically the start
> parameter is passed around with the put calls as
> ScriptableObject.getProperty(obj,name) traverses the prototype chain
> so if and when a setter is hit it can be called with the correct |
> this|.
> Kris
>
> On Oct 8, 10:26 am, "Peter Michaux" <[EMAIL PROTECTED]> wrote:
>> The documentation for Scriptable "put"
>>
>> http://www.mozilla.org/rhino/apidocs/org/mozilla/javascript/Scriptabl...)
>>
>> describes the second parameter "start"
>>
>> > Note that if a property a is defined in the prototype p
>> > of an object o, then evaluating o.a = 23 will cause set
>>
>> What does "set" mean specifically? I don't think "set" is referring to
>> some ECMA property that are usually in double brackets.
>>
>> > to be called on the prototype p with o as the start
>> > parameter. To preserve JavaScript semantics, it is the
>> > Scriptable object's responsibility to modify o.
>>
>> "the Scriptable object" refers to "o" or "p"? They could both be
>> ScriptableObject instances, yes?
>>
>> I don't understand what the above is trying to say. To me, evaluating
>> "o.a = 23" should set a value on "o" itself and not on o's prototype.
>> If objects "n" and "o" both share the same prototype "p", then
>> evaluating "o.a = 23" should not set the value "a" on prototype "p" as
>> that would affect "n". I imagine that Rhino is doing the right thing
>> but the above documentation seems misleading/confusing to me.
>>
>> > This design allows properties to be defined in prototypes
>> > and implemented in terms of getters and setters of Java
>> > values without consuming slots in each instance.
>>
>> Equally confused by this second paragraph.
>>
>> If someone explains what the documentation is trying to explain, I'll
>> submit a documentation patch.
>>
>> Thanks,
>> Peter
>
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