小编use*_*742的帖子

好的,一个问题,我想在Array函数中使用一组有区别的联合.在下面的代码,我定义类型ResultVari要么是Unknown或浮点值.我还为类型定义了中缀加运算符,仅当两个args都没有时才返回值Unknown.这很好用.

type ResultVari =
    | Unknown
    | Value of float
    static member (+) (a,b) =   // add two ResultVari's together
        match a,b with
        | Value(av),Value(bv) -> Value(av + bv)  // only has a value if both args do.
        | _ -> Unknown

(* Summation of array of ResultVari, such that if any are unknown then the result is Unknown *)
let example1 = [| Value(4.0); Value(5.5); Value(3.1) |]     // summation should be 12.6
let …