如何返回多个值并将它们分配给可变变量？

Question

这就是我到目前为止所拥有的.

let Swap (left : int , right : int ) = (right, left)

let mutable x = 5
let mutable y = 10

let (newX, newY) = Swap(x, y) //<--this works

//none of these seem to work
//x, y <- Swap(x, y)
//(x, y) <- Swap(x, y)
//(x, y) <- Swap(x, y)
//do (x, y) = Swap(x, y)
//let (x, y) = Swap(x, y)
//do (x, y) <- Swap(x, y)
//let (x, y) <- Swap(x, y)

Answer 1

你不能; 没有语法可以使用单个赋值更新"多个可变变量".当然可以

let newX, newY = Swap(x,y)
x <- newX
y <- newY

Answer 2

F# 与 C# 一样具有“通过引用”参数，因此您可以类似地编写经典的交换函数：

let swap (x: byref<'a>) (y: byref<'a>) =
    let temp = x
    x <- y
    y <- temp

let mutable x,y = 1,2
swap &x &y