From: hmmm <netcam@...>
Date: 2006-01-11T04:12:04+09:00
Subject: included module and scope confusion

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I am confused about modules and scope.

Here is a module:

module Crumbs
  MAX_CRUMBS =3D 10

  def self.included(mod)
    def cookies
      return @cookies =3D=3D nil ? Hash.new : @cookies
    end
  end

  def crumb_new( controller, action, params )
    cstr =3D controller + "^" + action
    if params !=3D nil && params.keys !=3D nil
      params.keys.each {|p|
        if params[p] !=3D nil
          cstr << "^" << p << "^" << params[p]
        end
      }
    end
    return cstr
  end

  def crumb_add( bite )
    cbs =3D @cookies
    puts cbs.class
    cbs =3D cbs[:rdf_crumbs]
    if cbs =3D=3D nil
      puts "crumb_add::cbs is nil!"
      cbs =3D[bite]
    else
      puts "crumb_add::cbs is OK!"
      cbs =3D cbs.split("|")
      #don't add a redundant
      if cbs.last =3D=3D bite
        return
      end
      # add to
      cbs << bite
      # cap the cookie queue at 5 using fifo
      if cbs.length > @@MAX_CRUMBS
        cbs.delete_at(0)
      end
    end
    crumbs_set( cbs )
  end

  def crumbs_set( mouthful )
    cr =3D ""
    mouthful.each { |m|
      if cr =3D=3D ""
        cr =3D m
      else
        cr << "|" << m
      end
    }
    puts cookies.class
    cookies[:rdf_crumbs] =3D cr
  end

  def get_crumbs()
    crs =3D @cookies["rdf_crumbs"]
    if crs =3D=3D nil
      return []
    else
      return crs.split("|")
    end
  end

end
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D

Here is a unit test:
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D
class Bread
  include Crumbs
  def initialize
    @cookies =3D Hash.new
  end
end

class CrumbTest < Test::Unit::TestCase

  attr :bread

  def setup
    @bread =3D Bread.new
  end

  def test_crumbs_simple
    @params =3D Hash.new
    bite =3Dbread.crumb_new( "test1", "test_action", @params )
    bread.crumb_add(bite)
    puts bite
    bite =3Dbread.crumb_new( "test2", "test_action_2", @params )
    bread.crumb_add(bite)
    puts bite
    bite =3Dbread.crumb_new( "test3", "test_action_3", @params )
    bread.crumb_add(bite)
    puts bite
    assert bite =3D=3D "test3^test_action_3"
    bites =3Dbread.get_crumbs()
    puts bites.class
    assert_equal bites.length, 3
  end
end

Here is the output:
------------------------------------------
test cookies! on Bread
Hash
crumb_add::cbs is nil!
sets Hash with test1^test_action
has 1
test1^test_action
Hash
crumb_add::cbs is nil!
sets Hash with test2^test_action_2
has 1
test2^test_action_2
Hash
crumb_add::cbs is nil!
sets Hash with test3^test_action_3
has 1
test3^test_action_3
------------------------------------------

And:
------------------------------------------
Test::Unit::AssertionFailedError: <1> expected but was <3>.
test/unit/crumbs_test.rb:62:in `test_crumbs_simple'
------------------------------------------

I have tried different ways, but can't get the Correct Way to have a module
insert a variable into the Class that includes it.  In this case it should
inject a @cookies hash, but in tests @cookies always gets reset to
Hash.new...

Excuse the inconsistencies in the code (towards @cookies) b/c I can't seem
to figure out the proper way.

So how do you add instance vars to a class from a module and how to
reference that attribute?  Or is this not the Right Ruby Way?

I have a lot of confusion about modules... suppose its my java funk :/

Please point me to any more docs on modules besides the ruby-lang snippet.

-netcam

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