区分联盟初始化

Question

有没有一种更简单的方法来使用F#初始化这副牌？

let create() = [ 0..12 ]

type Suit = 
    | Spades of list<int>
    | Hearts of list<int>
    | Clubs of list<int>
    | Diamonds of list<int>

let spades = create() |> Spades
let hearts = create() |> Hearts
let clubs = create() |> Clubs
let diamonds = create() |> Diamonds

具体来说,我想简化这四种套装的初始化.有更简单的方法吗？

我可以列举这个有区别的联盟的类型并将其分配给一些"甲板"结构吗？

注意:

我是F#的新手.如果这个问题似乎无知,请原谅我.

Answer 1

我不认为有更简洁的方式,但我也不会模仿这样的扑克牌,因为它无助于使非法国家无法代表.举个例子,我可以这样做:

> Spades [-1; 10; 100];;
val it : Suit = Spades [-1; 10; 100]

那有什么意思？

替代模型

相反,我可能会像这样模拟卡片:

type Suit = Diamonds | Hearts | Clubs | Spades
type Face =
    | Two | Three | Four | Five | Six | Seven | Eight | Nine | Ten
    | Jack | Queen | King | Ace

type Card = { Suit: Suit; Face: Face }

这将使您能够表达任何有效的卡:

> { Suit = Spades; Face = Ace };;
val it : Card = {Suit = Spades;
                 Face = Ace;}

另一方面,你不能表达invalid卡片:

> { Suit = Spades; Face = Hundred };;

  { Suit = Spades; Face = Hundred };;
  ------------------------^^^^^^^

stdin(4,25): error FS0039: The value or constructor 'Hundred' is not defined

初始化在这个模型中看起来有点麻烦,但另一方面,以下deck是一个不可变的值,所以一旦定义了,你就可以一次又一次地重复使用它.

let deck = [
    { Suit = Diamonds; Face = Two   };
    { Suit = Diamonds; Face = Three };
    { Suit = Diamonds; Face = Four  };
    { Suit = Diamonds; Face = Five  };
    { Suit = Diamonds; Face = Six   };
    { Suit = Diamonds; Face = Seven };
    { Suit = Diamonds; Face = Eight };
    { Suit = Diamonds; Face = Nine  };
    { Suit = Diamonds; Face = Ten   };
    { Suit = Diamonds; Face = Jack  };
    { Suit = Diamonds; Face = Queen };
    { Suit = Diamonds; Face = King  };
    { Suit = Diamonds; Face = Ace   };
    { Suit = Hearts;   Face = Two   };
    { Suit = Hearts;   Face = Three };
    { Suit = Hearts;   Face = Four  };
    { Suit = Hearts;   Face = Five  };
    { Suit = Hearts;   Face = Six   };
    { Suit = Hearts;   Face = Seven };
    { Suit = Hearts;   Face = Eight };
    { Suit = Hearts;   Face = Nine  };
    { Suit = Hearts;   Face = Ten   };
    { Suit = Hearts;   Face = Jack  };
    { Suit = Hearts;   Face = Queen };
    { Suit = Hearts;   Face = King  };
    { Suit = Hearts;   Face = Ace   };
    { Suit = Clubs;    Face = Two   };
    { Suit = Clubs;    Face = Three };
    { Suit = Clubs;    Face = Four  };
    { Suit = Clubs;    Face = Five  };
    { Suit = Clubs;    Face = Six   };
    { Suit = Clubs;    Face = Seven };
    { Suit = Clubs;    Face = Eight };
    { Suit = Clubs;    Face = Nine  };
    { Suit = Clubs;    Face = Ten   };
    { Suit = Clubs;    Face = Jack  };
    { Suit = Clubs;    Face = Queen };
    { Suit = Clubs;    Face = King  };
    { Suit = Clubs;    Face = Ace   };
    { Suit = Spades;   Face = Two   };
    { Suit = Spades;   Face = Three };
    { Suit = Spades;   Face = Four  };
    { Suit = Spades;   Face = Five  };
    { Suit = Spades;   Face = Six   };
    { Suit = Spades;   Face = Seven };
    { Suit = Spades;   Face = Eight };
    { Suit = Spades;   Face = Nine  };
    { Suit = Spades;   Face = Ten   };
    { Suit = Spades;   Face = Jack  };
    { Suit = Spades;   Face = Queen };
    { Suit = Spades;   Face = King  };
    { Suit = Spades;   Face = Ace   }; ]

虽然这看起来很乏味,但你只需要写一次.由于deck是值,因此可以使其成为属于模块的值.客户可以简单地使用此值,而不必自己初始化套牌.