Luaオブジェクト指向プログラミング。基本構造表の簡単な例

-- Czhenya Lua Object-Oriented
-- For an object, properties methods
--[[ Two ways to define functions
person.eat = function()
  print(person.name. "in writing LUA")
end
function person.eat()
  print(person.name.. "in writing LUA")
end
--]]
-- as a prototype
Person = {name = 'Czhena',age = 22}
function Person:eat()
  print(self.name. "s age is". .self.age)
end
function Person:new(o) -- return false if o is empty
  local t = o or {}
  --[[ Same result as set below, just two different ways
  setmetatable{t,self}
  self.__index=self
  --]]
  setmetatable(t,{__index = self}) -- Set metatable
  -- call an attribute that doesn't exist in t, it looks in the table referred to by __index
  return t
end
-- similar to creating an object via a constructor
person1 = Person:new({weight = 100})
person2 = Person:new()
print(person1.name)
print(person1.weight)
print(person2.name)
person1.name = "CZY" -- does not change the meta table, add to person.name
person1:eat()
person2:eat()
--Inheritance
Student = Person:new()
Student.grade = 1
stu1 = Student:new()
stu1:eat()
print(stu1.grade)

-- Use colons and dots to define functions, and suggest what to define functions with and what to call them with
person = {name="Czhenya",age=22}
function person:eat()
  print(self.name. "s age is". .self.age)
end
person.eat(person)
a = person
--colon calls self auto-assignment
a:eat()
-- When called by a dot, self is not automatically assigned a value, it must be passed as an argument
a.eat(a)