From: "Brian Schröder" <ruby.brian@...>
Date: 2005-11-16T19:20:14+09:00
Subject: Re: Nested classes

On 16/11/05, Groleo Marius <groleo@gmail.com> wrote:
> On 11/16/05, Brian Schr�der <ruby.brian@gmail.com> wrote:
> > On 16/11/05, Groleo Marius <groleo@gmail.com> wrote:
> > > On 11/16/05, Brian Schr�der <ruby.brian@gmail.com> wrote:
> > > >
> > > > What problem do you want to solve?
> > > >
> > > > Is this maybe nearer to you goals:
> > > >
> > > > class A
> > > >   class B
> > > >     def fun_b
> > > >       p "B"
> > > >     end
> > > >   end
> > > > end
> > > >
> > > > A::B.new.fun_b
> > > >
> > > > cheers,
> > > >
> > > > Brian
> > > >
> > >
> > > Consider the case when class B would have more member functions.
> > > In your example I would have to create a new object for each call to a
> > > B function.
> > > OTOH, a solution that I dont like :) could be :
> > >  class A
> > >    class B
> > >      def fun_b
> > >        p "B"
> > >      end
> > >      def other_b
> > >        p "_B"
> > >      end
> > >    end
> > >  end
> > > b = A::B.new
> > > b.fun_b
> > > b.other_b
> > >
> > > By the instantion of a new B object in the code from the first post,
> > > and refering to it, I was searching to keep a hierarchy inside a
> > > network protocol.
> > > I couldn't find any hint on google though :(
> > >
> >
> > Maybe you should look at the delegation pattern. That may be
> > applicable here. But I have not yet understood your use case. Could
> > you describe it in a bit more detail?
>
> Sure.
> Consider  a client script  that has to querry a server.
> The server operate on users/domains of a running qmail.
>
> So, I would have a class named Client, with the folowing members:
> login( user, pass ) logins to the remote administration server
> domain              an instantion of a domain class.
>
> OTOH Domain class has X member functions:
> add( domain_name)   adds a new domain
> remove
> update
>
> So a scenario would look like:
>
> c =Client.new     #creates a new Domain object
> c.login( "foo", "bar" )
> c.domain.add( "localdomain" )
>
> Now , back to the code ,the attr_reader was the magic word from what
> Pit posted .
> Maybe you too observed, but why in ruby
> this  attr_reader : b  is different from  attr_reader :b
>                    ^space                             ^no space
>

Because :b is the symbol :b while : b is a colon followed by a b which
is not allowed syntax here.

cheers,

Brian

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