轉換C＃結構，以F＃

Question

我有這樣的代碼在C＃：

namespace WumpusWorld 
    { 
     class PlayerAI 
     { 
      //struct that simulates a cell in the AI replication of World Grid 
      struct cellCharacteristics 
      { 
       public int pitPercentage; 
       public int wumpusPercentage; 
       public bool isPit; 
       public bool neighborsMarked; 
       public int numTimesvisited; 
      } 

      private cellCharacteristics[,] AIGrid;     //array that simulates World Grid for the AI 
      private enum Move { Up, Down, Right, Left, Enter, Escape }; //enum that represents integers that trigger movement in WumpusWorldForm class 
      Stack<int> returnPath;          //keeps track of each move of AI to trace its path back 
      bool returntoBeg;           //flag that is triggered when AI finds gold 
      int numRandomMoves;           //keeps track of the number of random moves that are done 

      public PlayerAI() 
      { 
       AIGrid = new cellCharacteristics[5, 5]; 
       cellCharacteristics c; 
       returntoBeg = false; 
       returnPath = new Stack<int>(); 
       numRandomMoves = 0; 

       for (int y = 0; y < 5; y++) 
       { 
        for (int x = 0; x < 5; x++) 
        { 
         c = new cellCharacteristics(); 
         c.isPit = false; 
         c.neighborsMarked = false; 
         c.numTimesvisited = 0; 

         AIGrid[x, y] = c; 
        } 
       } 
      } 
     } 
    } 

我不知道如何將這種C＃結構，以F＃轉換和實施struct到像我上面的代碼中的數組。

Answer 1

您可以使用struct關鍵字（如Stilgar所示）或使用Struct屬性（如下所示）來定義結構。我還補充說，初始化結構的構造：

[<Struct>] 
type CellCharacteristics = 
    val mutable p : int 
    val mutable w : int 
    val mutable i : bool 
    val mutable ne : bool 
    val mutable nu : int 

    new(_p,_w,_i,_ne,_nu) = 
    { p = _p; w = _w; i = _i; ne = _ne; nu = _nu } 

// This is how you create an array of structures and mutate it 
let arr = [| CellCharacteristics(1,2,true,false,3) |] 
arr.[0].nu <- 42 // Fields are public by default 

但是，一般不推薦使用可變的值類型。這會導致混淆行爲，代碼很難推理。這不僅僅在F＃中，即使在C＃和.NET中也是如此。在F＃中創建一個不變的結構也更容易：

// The fields of the strcuct are specified as part of the constructor 
// and are stored in automatically created (private) fileds 
[<Struct>] 
type CellCharacteristics(p:int, w:int, i:bool, ne:bool, nu:int) = 
    // Expose fields as properties with a getter 
    member x.P = p 
    member x.W = w 
    member x.I = i 
    member x.Ne = ne 
    member x.Nu = nu 

當使用一成不變的結構，你將不能修改該結構的各個字段。您需要替換數組中的整個結構值。您通常可以將計算實現爲結構的成員（例如Foo），然後只需編寫arr.[0] <- arr.[0].Foo()來執行更新。