From: Don French <dhf0820@...>
Date: 2010-04-27T06:35:07+09:00
Subject: Re: Semi global variables

On Apr 26, 9:02 am, Robert Klemme <shortcut...@googlemail.com> wrote:
> 2010/4/26 Don French <dhf0...@gmail.com>:
>
>
>
> > On Apr 25, 9:16 pm, Intransition <transf...@gmail.com> wrote:
> >> On Apr 25, 9:00 pm, Don French <dhf0...@gmail.com> wrote:
>
> >> > I have an application where multiple objects are created processing
> >> > different sets of data based upon a configuration specified. Each
> >> > object uses several other objects but those objects must use the
> >> > configuration initially set up in the first primary object.  Each of
> >> > the primary objects maintain their own configuration.
>
> >> > How can you have variables defined in the primary object that are
> >> > visible to the other objects it creates?
>
> >> Well, we would need to know more to be sure. But one possibility is to
> >> pass a reference to the primary object to all subsequent objects.
>
> > That is an option but I hate to pass around that to every object.
>
> You might hate it initially but you'll be glad when coming back to the
> code months later for maintenance.  Using global variables of any form
> makes code a) harder to read and understand and b) less flexible
> (because you are bound to that exact global variable).  Explicit
> passing of data is the better alternative most of the time.  You can
> still organize it in a way that it's not too much typing overhead.
>
> > class Driver
> >  def initialize
> >    live_data_handler = Handler.new('live')
> >    test_data_handler = Handler.new('test')
> >  end
>
> >  def handle_command
> >     do
> >       command, data = queuemanager.wait
> >       case command
> >         when 'processlive'
> >           live_data_handler.handle(data)
> >         when 'processtest'
> >           live_data_handler.handle(data)
>
> Shouldn't that read
>
> test_data_handler.handle(data)
>
> ?
>
> >       end
> >    until command == 'quit'
> >  end
> > end
>
> > class Handler
> >  def initialize(config)
> >   @config = getconfig(config)
> >   @otherconfiginfo = other
>
> Where do you get that "other" from?
>
> >  end
>
> >  def handle(data)
> >    lots_of_different_objects_created(data)
> >  end
> > end
>
> > this is an example of the structure.  same handler code but config
> > determines what to do and how.
>
> Kind regards
>
> robert
>
> --
> remember.guy do |as, often| as.you_can - without endhttp://blog.rubybestpractices.com/

Thanks.  Looks like I will just create a configuration object and pass
it around.

Other is just a place holder instead of showing more of the code.
There are lots of config things that are initialized.

Don Frenc