Ruby語言 (三)

#=> class more

    #繼承怎麼實現:

    class LittleBird < Bird
      def initialize name
        super(name)
      end
    end        

    #特殊屬性訪問控制:

    attr_reader :name
    attr_writer :sex
        
#=> module

    #interface怎麼寫:
    #ruby沒有interface,只有比interface更強大的module與mixin機制       

#=> module

    #"有邏輯實現的interface":

    module Eat
      def eat
        p "i can eat"
      end
    end

    module Sleep
      def sleep
        p "i can sleep"
      end
    end

    class Pig
      include Eat
      include Sleep
    end

    Pig.new.eat
    Pig.new.sleep
        
#=> module constants

    # module constants訪問:


    module Math
      PI = 3.14
    end

    Math::PI
        
#=> module more

    # module namespace:

    module Foo
      module Bar
        def self.say
          p "Hi"
        end
      end
    end

    Foo::Bar.say
            
	# another module namespace:

    module Foo
      class Bar
        def say
          p "Hi"
        end
      end
    end

    Foo::Bar.new.say
        
#=> module singleton

   # module的特殊用法singleton:


    module Item
      extend self
      
      def name
        p "i'm item"
      end
    end

    Item.name
        
#=> ruby more

    # monkey patch:


    class Fixnum
      def plus n
        self + n
      end
    end

    1.plus 3