From: Ara.T.Howard@...
Date: 2004-10-14T00:54:34+09:00
Subject: Re: Sharing variables across methods

On Thu, 14 Oct 2004, David Garamond wrote:

> When writing short scripts (several pages long) I often want to share
> some variables (like CGI object, DB connection object) in several
> methods. I often use globals for this:
>
>  $cgi = CGI.new('html3')
>  $conn = PGconn.connect(...)
>
>  def foo
>    $conn.exec(...)
>    $cgi.out { ... }
>  end
>
> When I don't want to see all those dollar signs, I use a wrapper method:
>
>  $_cgi = CGI.new('html3')
>  def cgi; $_cgi end
>
>  def foo
>    cgi.out { ... }
>  end
>
> But it still looks ugly to me. Any suggestion to make it more elegant?

what you are saying is that you want something that shares state and methods -
this is a perfect oportunity to create a class:

   class CGIApp
     def initialize opts = {}
       @cgi = CGI::new 'html3'
       @pgconn = PGconn::connect(*opts['pgconn'])
     end
     def foo
       @pgconn.exec ...
       @cgi.out ...
     end
   end

if you also need a global handle on the object created and, like in this case,
there can be only one of them extent at a time, you can hang some class
methods of the class to retrive the object - for instance use the multiton
pattern:

   class CGIApp
     class << self
       attr :instance
       def new(*a,&b); @instance ||= super; end
     end
   end

kind regards.

-a
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