From: ptkwt@...1.aracnet.com (Phil Tomson)
Date: 2002-01-31T11:24:57+09:00
Subject: Re: Newbie question about mixins

In article <a39k7j$jis$1@news.wrc.xerox.com>,
Mark Wilson <mwilson@crt.xerox.com> wrote:
>I have a module that I want to use as a mixin.  I have defined a method
>within the module that attempts to assign a value to a hash 'slot':
>
>    module myMod
First of all it should be:
     module MyMod
because module names should be capitalized.

>        def mixinMethod(param1, param2)
>            @hashVar[param1] = param2
>        end
>    end
>
>I include this module into my class, and call 'mixinMethod'.  I get a
>NameError because, apparently, I have not told the program that 'hashVar' is
>a hash table.  Where should I do a Hash.new() or other initialization?
>

Probably you should define it in your class's initialize:

   class
      include MyMod
      def initialize
         @hashVar = Hash.new()
      end
   end

OR you could do this:

     module MyMod

        def mixinMethod(param1, param2)
            unless defined? @hashVar
              @hashVar = {}
            end
            @hashVar[param1] = param2
        end
    end


>Thanks,
>Mark Wilson
>Xerox, The Document Company
>mwilson@crt.xerox.com
>

You're welcome.

Phil