Rails spinoffs - Feb 2008 - inheriting static/class methods with new prototype.js class creation

Hey all.

I want something like this to work:

var Foo = Class.create();
Foo.myStaticMethod = function(){alert("I''m a static
method!")};
Foo.myStaticMethod(); // works
var f = new Foo();
f.myStaticMethod(); // doesn''t work, but that''s good--I
don''t want it
to
var Bar = Class.create(Foo);
Bar.myStaticMethod(); // doesn''t work, undefined :(


I''ve seen a lot of posts on creating private instance methods and
class methods that don''t inherit, but I haven''t found anything
on
this.

Thanks in advance.
-Ian
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Spinoffs" group.
To post to this group, send email to
rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-spinoffs?hl=en
-~----------~----~----~----~------~----~------~--~---

Ian,

Object.extend(Bar, Foo) should do the trick.

- kangax

On Feb 18, 5:47 pm, "I. E. Smith-Heisters"
<i...-ZMJO0lPjCCA@public.gmane.org> wrote:
> Hey all.
>
> I want something like this to work:
>
> var Foo = Class.create();
> Foo.myStaticMethod = function(){alert("I''m a static
method!")};
> Foo.myStaticMethod(); // works
> var f = new Foo();
> f.myStaticMethod(); // doesn''t work, but that''s good--I
don''t want it
> to
> var Bar = Class.create(Foo);
> Bar.myStaticMethod(); // doesn''t work, undefined :(
>
> I''ve seen a lot of posts on creating private instance methods and
> class methods that don''t inherit, but I haven''t found
anything on
> this.
>
> Thanks in advance.
> -Ian
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Spinoffs" group.
To post to this group, send email to
rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-spinoffs?hl=en
-~----------~----~----~----~------~----~------~--~---

On Feb 19, 8:47 am, "I. E. Smith-Heisters"
<i...-ZMJO0lPjCCA@public.gmane.org> wrote:
> Hey all.
>
> I want something like this to work:
>
> var Foo = Class.create();
> Foo.myStaticMethod = function(){alert("I''m a static
method!")};
> Foo.myStaticMethod(); // works
> var f = new Foo();
> f.myStaticMethod(); // doesn''t work, but that''s good--I
don''t want it
> to
You added a property to Foo called myStaticMethod.  When you use the
new keyword, the object returned is constructed by Foo, it is not an
"instance" of Foo as you might expect in classic inheritance (although
it is still called an instance).

When you create f, Foo is not on it''s inheritance chain or in scope,
so neither is any property of Foo, including  myStaticMethod.

> var Bar = Class.create(Foo);
> Bar.myStaticMethod(); // doesn''t work, undefined :(
In classic prototype inheritance you would do:

  function Foo() {}
  Foo.prototype.myStaticMethod = function(){}

  var bar = new Foo();

  bar.myStaticMethod();  // ta da

> I''ve seen a lot of posts on creating private instance methods and
> class methods that don''t inherit, but I haven''t found
anything on
> this.
Javascript closures (and just about everything you need to know about
Identifier Resolution, Execution Contexts and Scope Chains):
<URL: http://www.jibbering.com/faq/faq_notes/closures.html >

JavaScript Inheritance articles (and other stuff):
<URL: http://javascript.crockford.com/ >


When you''re done with that, go over  the Class.create code in
Prototype.js.


--
Rob
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Spinoffs" group.
To post to this group, send email to
rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-spinoffs?hl=en
-~----------~----~----~----~------~----~------~--~---

It does indeed! Thanks.

On 2/18/08, kangax <kangax-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
>
> Ian,
>
> Object.extend(Bar, Foo) should do the trick.
>
> - kangax
>
> On Feb 18, 5:47 pm, "I. E. Smith-Heisters"
<i...-ZMJO0lPjCCA@public.gmane.org> wrote:
> > Hey all.
> >
> > I want something like this to work:
> >
> > var Foo = Class.create();
> > Foo.myStaticMethod = function(){alert("I''m a static
method!")};
> > Foo.myStaticMethod(); // works
> > var f = new Foo();
> > f.myStaticMethod(); // doesn''t work, but that''s
good--I don''t want it
> > to
> > var Bar = Class.create(Foo);
> > Bar.myStaticMethod(); // doesn''t work, undefined :(
> >
> > I''ve seen a lot of posts on creating private instance methods
and
> > class methods that don''t inherit, but I haven''t
found anything on
> > this.
> >
> > Thanks in advance.
> > -Ian
> >
>
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Spinoffs" group.
To post to this group, send email to
rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-spinoffs?hl=en
-~----------~----~----~----~------~----~------~--~---

On Feb 20, 4:02 am, "Ian Smith-Heisters"
<i...-ZMJO0lPjCCA@public.gmane.org> wrote:
> It does indeed! Thanks.

Now I''m confused, I thought you were after some kind of inheritance.
What kangax''s suggestion effectively does simply assigne a value to a
property:

  var Bar = Class.create(Foo);
  Bar.myStaticMethod = Foo.myStaticMethod;


Is that inheritance?


--
Rob
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Spinoffs" group.
To post to this group, send email to
rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-spinoffs?hl=en
-~----------~----~----~----~------~----~------~--~---

Rob,
This can hardly be called inheritance, indeed, but rather a naive way
of somewhat simulating it (manually copying "parent" object methods
into the "child"). There''s a patch in a trac [1] which
provides a much
more robust solution - Class.addClassMethods - it ensures that all
subclasses are extended with class (static) methods (when added via
addClasMethods).

[1] http://dev.rubyonrails.org/ticket/10089

Best,
kangax


On Feb 20, 1:56 am, RobG <rg...-AFFH1GffN5hPR4JQBCEnsQ@public.gmane.org>
wrote:
> On Feb 20, 4:02 am, "Ian Smith-Heisters"
<i...-ZMJO0lPjCCA@public.gmane.org> wrote:
>
> > It does indeed! Thanks.
>
> Now I''m confused, I thought you were after some kind of
inheritance.
> What kangax''s suggestion effectively does simply assigne a value
to a
> property:
>
>   var Bar = Class.create(Foo);
>   Bar.myStaticMethod = Foo.myStaticMethod;
>
> Is that inheritance?
>
> --
> Rob
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Spinoffs" group.
To post to this group, send email to
rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-spinoffs?hl=en
-~----------~----~----~----~------~----~------~--~---

agreed. But it works without requiring me to do any hackery to
Class.create() to do it implicitly.

On 2/19/08, RobG <rgqld-AFFH1GffN5hPR4JQBCEnsQ@public.gmane.org>
wrote:
>
>
>
>  On Feb 20, 4:02 am, "Ian Smith-Heisters"
<i...-ZMJO0lPjCCA@public.gmane.org> wrote:
>  > It does indeed! Thanks.
>
>
>  Now I''m confused, I thought you were after some kind of
inheritance.
>  What kangax''s suggestion effectively does simply assigne a value
to a
>  property:
>
>
>   var Bar = Class.create(Foo);
>
>   Bar.myStaticMethod = Foo.myStaticMethod;
>
>
>  Is that inheritance?
>
>
>
>  --
>  Rob
>
> >
>
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Spinoffs" group.
To post to this group, send email to
rubyonrails-spinoffs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-spinoffs-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-spinoffs?hl=en
-~----------~----~----~----~------~----~------~--~---