On Jun 10, 7:32 am, RobG <[EMAIL PROTECTED]> wrote:
> On Jun 10, 5:05 am, PragueExpat <[EMAIL PROTECTED]> wrote:
>
> > I posted this in comp.lang.javascript also, but would like to hear
> > from the jQuery group.
>
> Multi-posting is not liked:
>
> <URL:http://groups.google.com.au/group/comp.lang.javascript/browse_frm/thr...
>
>
>
> > I (think) that I've come up with a pattern that I haven't seen in any
> > publications so far and I would like some feedback. Basically, I was
> > looking for a way to inherit private functions and I came up with
> > this:
>
> > //base private object constructor
>
> > function priv(){
> > this.a = 1;
> > this.b = 2;
> > }
>
> That doesn't create any "private" variables, a and b will be public
> properties of the object returned when new priv() is called. It is
> also customary for constructor names to start with a capital letter,
> so:
>
the resulting object is contained in a private variable only, making
it private to the test variable - I didn't mean to imply that a,b,c
and d are themselves private - rather that the resulting object is
used in a private var and can be cloned and extended in a private
variable in a subclass
> function Priv(){ ... }
>
>
>
> > //private object constructor that inherits from base private object
>
> > function priv2(){
> > this.c = 3;
> > this.d = 4;}
>
> > priv2.prototype = new priv();
>
> It doesn't inherit anything from Priv, it inherits from
> priv.prototype.
>
> > //constructor that uses private object in private namespace
>
> > function ob(){
> > var _ = new priv2();
> > return {
> > go:function(){
> > alert(_.a);
> > }
> > }
> > }
>
> > var test = new ob();
>
> A pointless use of new since ob() returns a different object to that
> referenced by its this keyword. All of the properties of
> priv2.prototype are public, the only "private" variable is _ (a poor
> choice of variable name) as a result of the closure.
>
> As you were told in clj, the only effective way to make private
> variables in javascript is to use closures.
>
> > //returns 1
>
> > test.go();
>
> And this returns foo:
>
> priv2.prototype.a = 'foo';
> test.go();
>
> > //only go() is public
>
> The point of private variables is that you can only access them via
> privileged methods. Being able to set (or mask) a property using a
> public a access method means they aren't displaying the properties
> normally attributed to private variables.
>
> > test;
>
> ?
>
> > First of all, is this a known pattern? If so, sorry for the redundant
> > information. If not, are there any drawbacks that you can see?
>
> Yes, it doesn't do what you think it's doing.
>
> > The
> > advantage, as I see it, is that inherited objects can also inherit
> > private functions and properties for use.
>
> The "pattern" you've used does no such thing. The only private
> variable created is the one using a closure, which is a well known
> pattern.
>
> <URL:http://crockford.com/javascript/private.html>
> <URL:http://www.jibbering.com/faq/faq_notes/closures.html>
>
> --
> Rob
Although you make several valid points, your tone throughout is
unnecessarily abrasive. I was simply asking for feedback from other js
programmers about a possible new way of thinking about inheritance.
You might think about anger management therapy.
