The document discusses refactoring code by replacing methods with method objects. Specifically, it talks about extracting the body of a long or complex method into a new class, making the method body smaller and easier to understand. Instance variables can be used to share state between the original method and new method object. The goal is to break apart methods to make the code more readable and maintainable through refactoring.

1. RAILS CODE CLUB #2
+ Rails Tuesday
+ Rails Bridge 自主練習
+ BOARD GAME
19:20 開始

2. 上期回顧
• 1 - Intention revealing method
• 簡單來說就是註解變成 method
• 2 - Special case objects
• 從源頭解決 nil 要特殊處理的問題

3. 3 - REPLACE METHOD WITH
METHOD OBJECT
• 主要⺫⽬目的是關進去 refactoring
• 開⼀一個新的 class，method body 移過去
• 讀 code，下註解，把註解變成 method
• 必須跨 methods 的 local variable 改成 instance
variable
• 抽出的 method 請放成 private (關起來)

4. class OriginMethods
def a_fat_method
!
!
!
!
end
end
# $%@ + ($@# / ^%)
# && ^ %& * #%%^
# 看不懂的⻤⿁鬼
# and 100 lines...

5. class OriginMethods
def a_fat_method
!
!
!
!
end
end
class NewMethods
def perform
end
end
# $%@ + ($@# / ^%)
# && ^ %& * #%%^
# 看不懂的⻤⿁鬼
# and 100 lines...

6. class OriginMethods
def a_fat_method
!
!
!
!
end
end
class NewMethods
def perform
!
!
!
!
end
end
# $%@ + ($@# / ^%)
# && ^ %& * #%%^
# 看不懂的⻤⿁鬼
# and 100 lines...

7. class OriginMethods
def a_fat_method
!
!
!
!
end
end
class NewMethods
def perform
!
!
!
!
end
end
# $%@ + ($@# / ^%)
# && ^ %& * #%%^
# 看不懂的⻤⿁鬼
# and 100 lines...
NewMethods.new.perform

8. class NewMethods
!
!
!
!
def perform
File.open(??????????)
# ...
end
end
!
class OriginMethods
def a_fat_method(file_name)
NewMethods.new.perform
end
end
?

9. class NewMethods
!
!
!
!
def perform
File.open( )
# ...
end
end
!
class OriginMethods
def a_fat_method(file_name)
NewMethods.new
end
end

10. class NewMethods
!
!
!
!
def perform
File.open( )
# ...
end
end
!
class OriginMethods
def a_fat_method(file_name)
NewMethods.new
end
end
(file_name).perform

11. class NewMethods
!
!
!
!
def perform
File.open( )
# ...
end
end
!
class OriginMethods
def a_fat_method(file_name)
NewMethods.new
end
end
def initialize(file_name)
@file_name = file_name
end
(file_name).perform

12. class NewMethods
!
!
!
!
def perform
File.open( )
# ...
end
end
!
class OriginMethods
def a_fat_method(file_name)
NewMethods.new
end
end
@file_name
def initialize(file_name)
@file_name = file_name
end
(file_name).perform

14. 看懂以後
加⼊入註解
看懂以後
加⼊入註解
然後
註解變
method

15. 改成
instance variable