运算符重载

Basic-practice-of-FSharp/Basic-practice-of-FSharp.fsproj

@@ -19,5 +19,6 @@
     <Compile Include="PatternMatching.fs" />
     <Compile Include="ComputationExpressions.fs" />
     <Compile Include="ExceptionThrowing.fs" />
+    <Compile Include="OperatorOverloading.fs" />
   </ItemGroup>
 </Project>

Basic-practice-of-FSharp/OperatorOverloading.fs

@@ -0,0 +1,46 @@
+module OperatorOverloading
+// 运算符重载
+
+// 运算符不过是一种特殊形态的函数
+
+// 在类或者记录中重载运算符
+// static member (operator-symbols) (params) = body
+
+// 在全局作用域中存在运算符
+// let [inline] (operator-symbols) (params) = body
+
+// 请注意,在运算符重载中的运算符必须是静态的
+
+type Point(x: int, y: int) = 
+    member this.X = x
+    member this.Y = y
+    static member ( + ) (a: Point, b: Point) = Point(a.X + b.X, a.Y + b.Y)
+    override this.ToString() = $"X: {this.X}, Y: {this.Y}"
+
+let p1 = new Point(1, 3)
+let p2 = new Point(2, 4)
+
+p1 + p2 |> printfn "%A"
+
+let ( - ) (a: Point) (b: Point) = Point(a.X - b.X, a.Y - b.Y)
+
+p1 - p2 |> printfn "%A"
+
+// 对于重载一元前缀运算符可使用~标记
+// let [inline] (~+) (value) = body
+
+// 创建新的运算符
+// 可从!$%&*+-./<=>?@^|~中进行组合,注意~仅作为一元运算符的标记,并不属于自定义运算符序列中
+
+// 创建一个幂次运算符
+let inline ( ^ ) a b = a ** b   // ** 本身就是pow,我们仅对其进行了重命名,实际上可以let ( ^ ) = ( ** )
+
+2.0 ^ 4.0 |> printfn "%A"
+
+// 运算符是另一种形态的函数
+// 我们常见的|>运算符则是一个高阶函数, 将左侧表达式的至传递到右侧函数
+let inline ( |> ) p f = f p
+
+// 仅有一部分运算符可被作用于前缀运算符
+
+