From: Robert Klemme <bob.news@...>
Date: 2006-01-11T18:53:06+09:00
Subject: Re: included module and scope confusion

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hmmm wrote:

</snip>

> 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...

Of course because you assign it in initialize.

Two options:

1 Lazy init: You need to define cookies differently and access it always
through the getter method (attachment ex1.rb)

2 Init during constructor: you need to define #initialize in the module
and either leave initialize out of Bread or use super (attachment ex2.rb)

Module#included is completely wrong here as you do not want to do anything
to the class that uses the mod.

> 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 :/

Apparently. :-)

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



HTH

Kind regards

    robert

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	name="ex1.rb"
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	filename="ex1.rb"

module Crumbs=0A=
  MAX_CRUMBS =3D 10=0A=
=0A=
  def cookies=0A=
    # lazy init=0A=
    @cookies ||=3D {}=0A=
  end=0A=
=0A=
  def crumb_new( controller, action, params )=0A=
    cstr =3D controller + "^" + action=0A=
    if params !=3D nil && params.keys !=3D nil=0A=
      params.keys.each {|p|=0A=
        if params[p] !=3D nil=0A=
          cstr << "^" << p << "^" << params[p]=0A=
        end=0A=
      }=0A=
    end=0A=
    return cstr=0A=
  end=0A=
=0A=
  def crumb_add( bite )=0A=
    cbs =3D cookies=0A=
    puts cbs.class=0A=
    cbs =3D cbs[:rdf_crumbs]=0A=
    if cbs =3D=3D nil=0A=
      puts "crumb_add::cbs is nil!"=0A=
      cbs =3D[bite]=0A=
    else=0A=
      puts "crumb_add::cbs is OK!"=0A=
      cbs =3D cbs.split("|")=0A=
      #don't add a redundant=0A=
      if cbs.last =3D=3D bite=0A=
        return=0A=
      end=0A=
      # add to=0A=
      cbs << bite=0A=
      # cap the cookie queue at 5 using fifo=0A=
      if cbs.length > @@MAX_CRUMBS=0A=
        cbs.delete_at(0)=0A=
      end=0A=
    end=0A=
    crumbs_set( cbs )=0A=
  end=0A=
=0A=
  def crumbs_set( mouthful )=0A=
    cr =3D ""=0A=
    mouthful.each { |m|=0A=
      if cr =3D=3D ""=0A=
        cr =3D m=0A=
      else=0A=
        cr << "|" << m=0A=
      end=0A=
    }=0A=
    puts cookies.class=0A=
    cookies[:rdf_crumbs] =3D cr=0A=
  end=0A=
=0A=
  def get_crumbs()=0A=
    crs =3D cookies["rdf_crumbs"]=0A=
    if crs =3D=3D nil=0A=
      return []=0A=
    else=0A=
      return crs.split("|")=0A=
    end=0A=
  end=0A=
=0A=
end=0A=
=0A=
=0A=
class Bread=0A=
  include Crumbs=0A=
end=0A=

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module Crumbs=0A=
  MAX_CRUMBS =3D 10=0A=
=0A=
  attr_reader :cookies=0A=
=0A=
  def initialize(*a,&b)=0A=
    super=0A=
    @cookies =3D {}=0A=
  end=0A=
=0A=
  def crumb_new( controller, action, params )=0A=
    cstr =3D controller + "^" + action=0A=
    if params !=3D nil && params.keys !=3D nil=0A=
      params.keys.each {|p|=0A=
        if params[p] !=3D nil=0A=
          cstr << "^" << p << "^" << params[p]=0A=
        end=0A=
      }=0A=
    end=0A=
    return cstr=0A=
  end=0A=
=0A=
  def crumb_add( bite )=0A=
    cbs =3D @cookies=0A=
    puts cbs.class=0A=
    cbs =3D cbs[:rdf_crumbs]=0A=
    if cbs =3D=3D nil=0A=
      puts "crumb_add::cbs is nil!"=0A=
      cbs =3D[bite]=0A=
    else=0A=
      puts "crumb_add::cbs is OK!"=0A=
      cbs =3D cbs.split("|")=0A=
      #don't add a redundant=0A=
      if cbs.last =3D=3D bite=0A=
        return=0A=
      end=0A=
      # add to=0A=
      cbs << bite=0A=
      # cap the cookie queue at 5 using fifo=0A=
      if cbs.length > @@MAX_CRUMBS=0A=
        cbs.delete_at(0)=0A=
      end=0A=
    end=0A=
    crumbs_set( cbs )=0A=
  end=0A=
=0A=
  def crumbs_set( mouthful )=0A=
    cr =3D ""=0A=
    mouthful.each { |m|=0A=
      if cr =3D=3D ""=0A=
        cr =3D m=0A=
      else=0A=
        cr << "|" << m=0A=
      end=0A=
    }=0A=
    puts cookies.class=0A=
    cookies[:rdf_crumbs] =3D cr=0A=
  end=0A=
=0A=
  def get_crumbs()=0A=
    crs =3D @cookies["rdf_crumbs"]=0A=
    if crs =3D=3D nil=0A=
      return []=0A=
    else=0A=
      return crs.split("|")=0A=
    end=0A=
  end=0A=
=0A=
end=0A=
=0A=
=0A=
class Bread=0A=
  include Crumbs=0A=
  # if initialize is used you must use super=0A=
  # otherwise just leave out initialize=0A=
  def initialize=0A=
    super=0A=
    # initialization specific to Bread here=0A=
  end=0A=
end=0A=

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