Hi,
It's certainly an interesting approach. :-) Some observations:
1. It works; kudos. It's a bit like a dog riding a bicycle, but
still...
2. You'd have to document like *crazy* the fact that the code passed
to the Class function *isn't* evaluated in the apparent lexical scope,
but rather in the really very special lexical scope created within the
Class function. (Well, actually, it's evaluated in both, but the
second is the one that will get used.) Users failing to appreciate
the subtleties related to that would tend to run into difficult-to-
track-down bugs, particularly related to closures. And *they'd* have
to document it like crazy in their own code, as well, so anyone
picking it up is forewarned. Maintenance nightmares loom.
3. Debugging would tend to be fairly difficult, what with the class
and all of its member functions being within the eval, not (again)
actually where they appear to be. I expect over time that JavaScript
debuggers will handle debugging eval'd code more and more elegantly
(certainly there is effort being made there), but for the moment...
4. The code for classes defined in this way is evaluated twice, once
in the course of the main script being evaluated, and then again when
Class is called. Given that page load times are king, this isn't
ideal although I'm sure it happens fairly quickly.
5. Regarding this:
> ret.prototype=Initalizer.prototype;
>
> for(var p in
> Initalizer.prototype)ret.prototype[p]=Initalizer.prototype[p];
Given the assignment in the first line, what is the purpose of the
loop following it? Genuine question, not a dig -- am I missing a
subtlety? Seems likely I am.
6. Style point: You declare 'p' at least three times, which various
lint tools may complain about although it's allowed by the ECMA spec.
(It Really Shouldn't Be, but it is.)
Thanks for the post -- it's interesting. Very much about tradeoffs,
cost/benefit. For me, most of the time, I think the cost would tend
to be too high, but it's still an interesting approach to the old
problem.
--
T.J. Crowder
tj / crowder software / com
On May 13, 7:22 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote:
> /*author:[EMAIL PROTECTED]/
> function Class(Initalizer,SuperClasses)
> {
> if(!SuperClasses)SuperClasses=[];
> var ret=function(){
> for(var i=0;i<SuperClasses.length;i++)
> {
> SuperClasses[i].call(this);
> }
>
> var $private={};
> var $public=this;
> var $static=ret;
>
> with($static){
> with($private){
> with($public){
>
> eval("("+Initalizer+").apply(this,arguments)");
> }
> }
> }
> return this;
> }
>
> ret.prototype=Initalizer.prototype;
>
> for(var p in
> Initalizer.prototype)ret.prototype[p]=Initalizer.prototype[p];
> for(var p in Initalizer)ret[p]=Initalizer[p];
> for(var i=0;i<SuperClasses.length;i++)
> {
> for(var p in SuperClasses[i].prototype)
> {
> ret.prototype[p]=SuperClasses[i].prototype[p]
> }
> }
> return ret;
>
> }
>
> /*
> function alert(s)
> {
> WScript.echo(s);}
>
> */
>
> /***********************************************
> Example：public static private
> ************************************************/
>
> var test1=new Class(function(){
>
> //v1 is public
> $public.v1=1;
>
> //v2 is private
> $private.v2=2;
>
> //define public variable with this
> this.vv1=2;
>
> //public function member
> $public.show=function(){
> //visit public and private variable
> alert(v1);
> alert(v2);
> }
> $public.set_static=function(v){
> $static.v3=v;
> }
>
> });
>
> var obj=new test1();
>
> //visit public variable
> alert(obj.v1);
> alert(obj.vv1);
>
> //try to visit private variable
> alert(obj.v2);
>
> //call public member function
> obj.show();
>
> //set static variable
> obj.set_static(10);
> //visit static variable from class
> alert(test1.v3);
>
> /***********************************************
> Example:multi-inherit
> ************************************************/
> var parent=function(){this.v4=6};
> parent.prototype.v5=1000;
>
> var test2=new Class(function(){
> $public.show2=function(){
> alert(this.v1);
> alert(v4);
> alert(v5);
> }
>
> },[test1,parent]);
>
> var obj=new test2();
> obj.show2();
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