Subj : Re: Properties not defined with JS_DefineProperty possible?
To   : netscape.public.mozilla.jseng
From : Thomas Sondergaard
Date : Sat Jan 15 2005 12:53 pm

On Sat, 08 Jan 2005 14:06:46 -0800, Brendan Eich wrote:

> Of course -- JSClass.getProperty and JSClass.setProperty can mirror 
> changes from and to your std::map.  You can set the JSClass.flags bit 
> JSCLASS_SHARE_ALL_PROPERTIES to avoid any parallel map being managed by 
> SpiderMonkey.  Then for each get or set, the appropriate JSClass hook 
> will be called and you can fetch or store using your map.

Hi Brendan,

Yes, I realize that I don't have to keep *values* in sync and that I can
have spidermonkey invoke the get/setProperty (JSPropertyOp) to get/set the
value from my native object, but can I avoid having to tell spidermonkey
what properties (names!) exist up front with
JSDefineProperty/JSDefineProperties?

As an example, let's say I have defined an object called 'data' and I want
the properties on it to reflect the contents of my c++ std::map<string,
string>. So if the expression "data['noOfImages']" (or "data.noOfImages")
is evaluated how does the js engine know which jsid to pass to my
getPropertyOp if I have not previously told the engine that the object has
a property with that name using JSDefinePropert*? Is this possible? What
I'm thinking of is a hook that the engine will call to lookup properties
on an object dynamically.

Cheers,

Thomas

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