装飾モード--lua実現

Person = {}  
  
Decorator = {}  
  
function Person:new(o)  
    o = o or {}  
    setmetatable(o,self)  
    self.__index = self  
    return o;  
end  
  
function Person:Show()  
    print("   ")  
end  
  
Decorator = Person:new{component = nil}  
  
function Decorator:Decorate(com)  
    self.component = com  
end  
  
function Decorator:Show()  
    print("     ")  
end  
  
Shirt = Decorator:new()  
  
  
function Shirt:Show()  
    print("    ")  
    if self.component ~= nil then  
        self.component:Show()  
    end  
end  
  
  
  
Trouser = Decorator:new()  
  
function Trouser:Show()  
    print("    ")  
    if self.component ~= nil then  
        self.component:Show()  
    end  
end  
  
Shoe = Decorator:new()  
  
function Shoe:Show()  
    print("    ")  
    if self.component ~= nil then  
        self.component:Show()  
    end  
end  
  
person = Person:new()  
  
shirt = Shirt:new()  
shirt:Decorate(person)  
  
trouser = Trouser:new()  
trouser:Decorate(shirt)  
  
shoe = Shoe:new()  
shoe:Decorate(trouser)  
shoe:Show()