136 lines
3.3 KiB
Plaintext
136 lines
3.3 KiB
Plaintext
// 演示 Snow OOP 四大要点：封装、继承、多态、重载
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module: Main
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// 封装：基类 Animal
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struct: Animal
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fields:
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declare name: string
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init:
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params:
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n: string
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body:
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this.name = n
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end body
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end init
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// 封装：提供只读访问器
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function: getName
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returns: string
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body:
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return this.name
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end body
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end function
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// 多态：基类方法，默认虚
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function: speak
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returns: void
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body:
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os.print(this.name + " makes a sound.")
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end body
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end function
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// 重载示例：同名 eat，不同参数
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function: eat
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params:
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food: string
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returns: void
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body:
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os.print(this.name + " eats " + food)
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end body
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end function
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function: eat
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params:
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times: int
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returns: void
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body:
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os.print(this.name + " eats " + times + " times.")
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end body
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end function
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end struct
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// 继承 + 多态：Dog
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struct: Dog extends Animal
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init:
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params:
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n: string
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body:
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super(n)
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end body
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end init
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// 重写 speak
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function: speak
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returns: void
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body:
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os.print(this.name + " says: Woof!")
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end body
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end function
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end struct
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// 继承 + 多态：Cat
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struct: Cat extends Animal
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init:
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params:
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n: string
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body:
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super(n)
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end body
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end init
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// 重写 speak
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function: speak
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returns: void
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body:
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os.print(this.name + " says: Meow!")
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end body
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end function
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end struct
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// 多态演示函数
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function: letAnimalSpeak
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params:
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a: Animal
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returns: void
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body:
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// 调用多态方法
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a.speak()
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end body
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end function
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// 程序入口
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function: main
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returns: void
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body:
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// 基类结构体
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declare a: Animal = new Animal("GenericAnimal")
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a.speak() // -> GenericAnimal makes a sound.
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a.eat("food") // -> GenericAnimal eats food
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a.eat(2) // -> GenericAnimal eats 2 times.
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// 子结构体 Dog
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declare d: Dog = new Dog("Buddy")
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d.speak() // -> Buddy says: Woof!
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d.eat("bone") // 调用基类 eat(String)
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d.eat(3) // 调用基类 eat(int)
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// 子类结构体 Cat
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declare c: Cat = new Cat("Kitty")
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c.speak() // -> Kitty says: Meow!
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c.eat("fish")
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c.eat(1)
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// 多态：父类引用指向子类结构体
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declare poly: Animal = new Dog("Max")
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letAnimalSpeak(poly) // -> Max says: Woof!
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poly = new Cat("Luna")
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letAnimalSpeak(poly) // -> Luna says: Meow!
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end body
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end function
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end module
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