Inter-class use of variables in ruby -

i'm trying create class instance variables can linked , manipulated separate class. here's code:

class product   attr_accessor :name, :quantity   def initialize(name, quantity)     @name = name     @quantity = quantity   end end  class production   def initialize(factory)     @factory = factory   end   def create     "#{@name}: #{@factory}"   end end 

basically, i'd able use attributes instance of product class in production class. if = product.new('widget', 100), want able call a.name variable in instance of production. test have:

a = product.new('widget', 100) b = production.new('building 1') puts b.create('building 1') 

however, it's returning following:

: building 1 

instead of

widget: building 1 

any ideas what's going wrong? i'd add, subtract, etc. quantity. i'm hoping if figure out how link name property can same quantity pretty easily.

first of all, want produce product during production, production must know product. can example pass product argument create:

class production   def initialize(factory)     @factory = factory   end    def create(product)     "#{product.name}: #{@factory}"   end end  product = product.new('thingy', 123) production = production.new('acme') puts production.create(product) #=> "thingy: acme" 

or store in instance variable if need across entire production class:

class production   def initialize(factory, product)     @factory = factory     @product = product   end    def create     "#{@product.name}: #{@factory}"   end end  product = product.new('thingy', 123) production = production.new('acme', product) puts production.create #=> "thingy: acme"