###8. module intro
####8.1 Getting Modular
module only hold behaviour,unlike class which hold both behaviour and state
a module can not be instantiated, but can be included in a class
module WarmUp
def push_ups
"Ha Ha Ha,I am learning !"
end
end
class Gym
include WarmUp
def pp
"I am pp"
end
end
class Dojo
include WarmUp
def teng
"Bo zi Teng!"
end
end
p Gym.new.push_ups #Ha Ha Ha,I am learning !
p Dojo.new.push_ups #Ha Ha Ha,I am learning !
Module is the superclass of Class, so this means that all classes are also modules, and can be used as such
module WarmUp
end
puts WarmUp.class #Module
puts Class.superclass #Module
puts Module.superclass #Object
module Perimeter
def perimeter
sides.inject(0) { |sum, side| sum + side }
end
end
class Rectangle
include Perimeter
def initialize(length, breadth)
@length = length
@breadth = breadth
end
def sides
[@length, @breadth, @length, @breadth]
end
end
class Square
include Perimeter
def initialize(side)
@side = side
end
def sides
[@side, @side, @side, @side]
end
end
####8.2 Modules as Namespaces
利用namespace避免命名冲突
Module Perimeter
class Array
def initialize
@size = 400
end
end
end
our_array = Perimeter::Array.new
ruby_array = Array.new
p our_array.class #Perimeter::Array
p ruby_array.class #Array
Constant lookup (module 中的常量访问)
module Dojo
A = 4
module Kata
B = 6
module Rou
class ScopeIn
def push
8
end
end
end
end
end
A = 14
B = 16
C = 18
puts "A - #{A}" # A - 14
puts "Dojo::A - #{Dojo::A}" # Dojo::A - 4
puts "B - #{B}" # B - 16
puts "Dojo::Kata::B - #{Dojo::Kata::B}" # Dojo::Kata::B - 6
puts "C - #{C}" # C - 18
puts "Dojo::Kata::Rou::ScopeIn.new.push - #{Dojo::Kata::Rou::ScopeIn.new.push}" # Dojo::Kata::Rou::ScopeIn.new.push - 8
module Kata
A = 5
module Dojo
p A
B = 9
A = 7
class ScopeIn
def push
A
end
end
end
end
p Kata::Dojo::ScopeIn.new.push #先输出5 然后输出7
Kata::Dojo::ScopeIn::A = 10
p Kata::Dojo::ScopeIn.new.push #10
