Problem extending (adding methods) to class

ruby-talk
21

So my question again is: are classes declared within a module
typically/always factory classes like this -- i mean with singleton new
methods?

Singleton new methods are rare (IO.new, Class.new, Struct.new ..) and
out of these only IO gives the expected behavior when you subclass i.e
Subclass.new.class == Subclass.
Classes defined inside modules are primarily for namespacing.

Perhaps I should look thru the source code of Facets or some other
project to jump-start my ruby. Any suggestions?

Sure Facets has plenty of code samples. RubyQuiz is another.

--Cheers
--Ragav

22

David A. Black wrote:

Why not use a module?

module MyForm
   attr_accessor :myfields
   def get_fields
     @myfields
   end
end

class Ncurses::Form::FORM
   include MyForm
end

Interesting. But sorry if I am missing something. as I understand it, i
can't subclass a module, nor class Ncurses::Form::FORM. So i wont be
able to subclass this, right ?

···

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23

Hi --

···

On Fri, 3 Oct 2008, Nit Khair wrote:

David A. Black wrote:

Why not use a module?

module MyForm
   attr_accessor :myfields
   def get_fields
     @myfields
   end
end

class Ncurses::Form::FORM
   include MyForm
end

Interesting. But sorry if I am missing something. as I understand it, i
can't subclass a module, nor class Ncurses::Form::FORM. So i wont be
able to subclass this, right ?

It would still have the same 'new' issue. I'm suggesting, though, that
modules might be a good alternative to subclassing.

David

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24

It would still have the same 'new' issue. I'm suggesting, though, that
modules might be a good alternative to subclassing.

David

But modules can't maintain state, right.

While refactoring, i began dumping a lot of methods in a Module.

Then i needed differential behavior based on "kind_of", e.g. a basic
key_handler, a key_handler for tabular forms etc. The cleanest way that
i could think of was having the form objects having their own key
handling.
So i needed to differentiate forms based on behaviour. Thus I have a
heirarchy of forms and applications. The appropriate handler is called
based on what kind of form was created.

I am really new here, and struggling with concepts, but i understand
that yuo can have only one parent/super class, so modules help out in
acquiring more behavior (sort of multiple inheritance).

I'm suggesting, though, that
modules might be a good alternative to subclassing.

However, in the subclassing I am doing, the objects my application
consists of (composition) are descending from their own super-classes.
Yes, they still call "static" methods of the original module i created
(i mean convenience methods like printing errors, statuses etc).

This is why i was asking (on another thread, too) of actual projects
whose source one can learn these things from ( as against books,
samples, examples etc of which i have read enough - but will keep
reading!).

Perhaps the ruby source itself will be good quality - i really need to
see how real-life medium size projects in ruby are organized, classed
etc.

···

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