您可以重新定义或重载F#中可用的大多数内置运算符.因此,程序员也可以使用具有用户定义类型的运算符.
运算符是具有特殊名称的函数,括在括号中.必须将它们定义为静态类成员.与任何其他函数一样,重载运算符具有返回类型和参数列表.
以下示例显示了+运算符复数 :
//overloading + operator static member (+) (a : Complex, b: Complex) = Complex(a.x + b.x, a.y + b.y)
上述函数为用户定义的类Complex实现了加法运算符(+).它添加了两个对象的属性并返回生成的Complex对象.
以下程序显示完整的实现 :
//implementing a complex class with +, and - operators //overloaded type Complex(x: float, y : float) = member this.x = x member this.y = y //overloading + operator static member (+) (a : Complex, b: Complex) = Complex(a.x + b.x, a.y + b.y) //overloading - operator static member (-) (a : Complex, b: Complex) = Complex(a.x - b.x, a.y - b.y) // overriding the ToString method override this.ToString() = this.x.ToString() + " " + this.y.ToString() //Creating two complex numbers let c1 = Complex(7.0, 5.0) let c2 = Complex(4.2, 3.1) // addition and subtraction using the //overloaded operators let c3 = c1 + c2 let c4 = c1 - c2 //printing the complex numbers printfn "%s" (c1.ToString()) printfn "%s" (c2.ToString()) printfn "%s" (c3.ToString()) printfn "%s" (c4.ToString())
编译并执行程序时,它会产生以下输出 :
7 5 4.2 3.1 11.2 8.1 2.8 1.9