Magic 8 Ball

Magic 8 Ball in your console/terminal

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open System

type Rnd = { rnd : Random }
let createRndWithSeed (seed) = { rnd = new Random(seed) }
let inline precondition cond dueTo = 
    if (not cond) then 
        failwith ("precondition violation: " + dueTo)
//[0, 1)
let uniform (r : Rnd) = r.rnd.NextDouble()
//[0, n)
let uniformInt (r : Rnd) n = 
    precondition (n > 0) "less or equal than 0"
    r.rnd.Next(n)
//[n, m)
let uniformRange (r : Rnd) n m = 
    precondition (m > n) "invalid range"
    n + uniform r * (m - n)
//[n, m)
let uniformIntRange (r : Rnd) n m = 
    precondition (m > n) "invalid range"
    precondition (int64 (m - n) < int64 Int32.MaxValue) "invalid range"
    n + uniformInt r (m - n)
let shuffle (r : Rnd) (xs : 'a array) =
    precondition (xs <> null) "array is null"
    let n = xs |> Array.length
    for i = 0 to n - 1 do
        let j = i + uniformInt r (n - i)
        let temp = xs.[i]
        xs.[i] <- xs.[j]
        xs.[j] <- temp

//Magic 8 Ball (https://en.wikipedia.org/wiki/Magic_8-Ball)
let magic8Ball () =
    let magic8BallAnswers = 
        [|
            //positive
            "It is certain";
            "It is decidedly so";
            "Without a doubt";
            "Yes, definitely";
            "You may rely on it";
            "As I see it, yes";
            "Most likely";
            "Outlook good";
            "Yes";
            "Signs point to yes";
            //neutral
            "Reply hazy try again";
            "Ask again later";
            "Better not tell you now";
            "Cannot predict now";
            "Concentrate and ask again";        
            //negative
            "Don't count on it";
            "My reply is no";
            "My sources say no";
            "Outlook not so good";
            "Very doubtful"
        |]
    let rec loop (f : unit -> int) =
        Console.Title <- "The wonderful Magic 8 Ball. Ask me something..."
        printfn "Magic ball: What's your question?"
        printf "You: "
        let ask = Console.ReadLine()
        if String.IsNullOrEmpty(ask) then ()
        else 
            printfn "Magic ball: %s" magic8BallAnswers.[f ()]
            loop f
    let n = magic8BallAnswers |> Array.length
    let now = DateTime.Now
    let r = createRndWithSeed (now.Millisecond + now.Second * 1000)
    magic8BallAnswers |> shuffle r 
    loop (fun () -> uniformIntRange r 0 n)

magic8Ball ()

(*
    Magic ball: What's your question?
    You: Will I be rich?
    Magic ball: My sources say no
    Magic ball: What's your question?
    You: Will I be famous?
    Magic ball: Concentrate and ask again
    Magic ball: What's your question?
    You: Will I be famous?
    Magic ball: Cannot predict now
    Magic ball: What's your question?
    You: Will my team win the championship?
    Magic ball: Very doubtful
    Magic ball: What's your question?
    You: Will I win the first prize?
    Magic ball: Signs point to yes
    Magic ball: What's your question?
    You:
*)

namespace System

type Rnd =
{rnd: Random;}

Full name: Script.Rnd

Rnd.rnd: Random

Multiple items
type Random =
  new : unit -> Random + 1 overload
  member Next : unit -> int + 2 overloads
  member NextBytes : buffer:byte[] -> unit
  member NextDouble : unit -> float

Full name: System.Random

--------------------
Random() : unit
Random(Seed: int) : unit

val createRndWithSeed : seed:int -> Rnd

Full name: Script.createRndWithSeed

val seed : int

val precondition : cond:bool -> dueTo:string -> unit

Full name: Script.precondition

val cond : bool

val dueTo : string

val not : value:bool -> bool

Full name: Microsoft.FSharp.Core.Operators.not

val failwith : message:string -> 'T

Full name: Microsoft.FSharp.Core.Operators.failwith

val uniform : r:Rnd -> float

Full name: Script.uniform

val r : Rnd

Random.NextDouble() : float

val uniformInt : r:Rnd -> n:int -> int

Full name: Script.uniformInt

val n : int

Random.Next() : int
Random.Next(maxValue: int) : int
Random.Next(minValue: int, maxValue: int) : int

val uniformRange : r:Rnd -> n:float -> m:float -> float

Full name: Script.uniformRange

val n : float

val m : float

val uniformIntRange : r:Rnd -> n:int -> m:int -> int

Full name: Script.uniformIntRange

val m : int

Multiple items
val int64 : value:'T -> int64 (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.int64

--------------------
type int64 = Int64

Full name: Microsoft.FSharp.Core.int64

--------------------
type int64<'Measure> = int64

Full name: Microsoft.FSharp.Core.int64<_>

type Int32 =
  struct
    member CompareTo : value:obj -> int + 1 overload
    member Equals : obj:obj -> bool + 1 overload
    member GetHashCode : unit -> int
    member GetTypeCode : unit -> TypeCode
    member ToString : unit -> string + 3 overloads
    static val MaxValue : int
    static val MinValue : int
    static member Parse : s:string -> int + 3 overloads
    static member TryParse : s:string * result:int -> bool + 1 overload
  end

Full name: System.Int32

field int.MaxValue = 2147483647

val shuffle : r:Rnd -> xs:'a array -> unit (requires equality)

Full name: Script.shuffle

val xs : 'a array (requires equality)

type 'T array = 'T []

Full name: Microsoft.FSharp.Core.array<_>

type Array =
  member Clone : unit -> obj
  member CopyTo : array:Array * index:int -> unit + 1 overload
  member GetEnumerator : unit -> IEnumerator
  member GetLength : dimension:int -> int
  member GetLongLength : dimension:int -> int64
  member GetLowerBound : dimension:int -> int
  member GetUpperBound : dimension:int -> int
  member GetValue : [<ParamArray>] indices:int[] -> obj + 7 overloads
  member Initialize : unit -> unit
  member IsFixedSize : bool
  ...

Full name: System.Array

val length : array:'T [] -> int

Full name: Microsoft.FSharp.Collections.Array.length

val i : int

val j : int

val temp : 'a (requires equality)

val magic8Ball : unit -> unit

Full name: Script.magic8Ball

val magic8BallAnswers : string []

val loop : ((unit -> int) -> unit)

val f : (unit -> int)

type unit = Unit

Full name: Microsoft.FSharp.Core.unit

Multiple items
val int : value:'T -> int (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.int

--------------------
type int = int32

Full name: Microsoft.FSharp.Core.int

--------------------
type int<'Measure> = int

Full name: Microsoft.FSharp.Core.int<_>

type Console =
  static member BackgroundColor : ConsoleColor with get, set
  static member Beep : unit -> unit + 1 overload
  static member BufferHeight : int with get, set
  static member BufferWidth : int with get, set
  static member CapsLock : bool
  static member Clear : unit -> unit
  static member CursorLeft : int with get, set
  static member CursorSize : int with get, set
  static member CursorTop : int with get, set
  static member CursorVisible : bool with get, set
  ...

Full name: System.Console

property Console.Title: string

val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn

val printf : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printf

val ask : string

Console.ReadLine() : string

Multiple items
type String =
  new : value:char -> string + 7 overloads
  member Chars : int -> char
  member Clone : unit -> obj
  member CompareTo : value:obj -> int + 1 overload
  member Contains : value:string -> bool
  member CopyTo : sourceIndex:int * destination:char[] * destinationIndex:int * count:int -> unit
  member EndsWith : value:string -> bool + 2 overloads
  member Equals : obj:obj -> bool + 2 overloads
  member GetEnumerator : unit -> CharEnumerator
  member GetHashCode : unit -> int
  ...

Full name: System.String

--------------------
String(value: nativeptr<char>) : unit
String(value: nativeptr<sbyte>) : unit
String(value: char []) : unit
String(c: char, count: int) : unit
String(value: nativeptr<char>, startIndex: int, length: int) : unit
String(value: nativeptr<sbyte>, startIndex: int, length: int) : unit
String(value: char [], startIndex: int, length: int) : unit
String(value: nativeptr<sbyte>, startIndex: int, length: int, enc: Text.Encoding) : unit

String.IsNullOrEmpty(value: string) : bool

val now : DateTime

Multiple items
type DateTime =
  struct
    new : ticks:int64 -> DateTime + 10 overloads
    member Add : value:TimeSpan -> DateTime
    member AddDays : value:float -> DateTime
    member AddHours : value:float -> DateTime
    member AddMilliseconds : value:float -> DateTime
    member AddMinutes : value:float -> DateTime
    member AddMonths : months:int -> DateTime
    member AddSeconds : value:float -> DateTime
    member AddTicks : value:int64 -> DateTime
    member AddYears : value:int -> DateTime
    ...
  end

Full name: System.DateTime

--------------------
DateTime()
   (+0 other overloads)
DateTime(ticks: int64) : unit
   (+0 other overloads)
DateTime(ticks: int64, kind: DateTimeKind) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, calendar: Globalization.Calendar) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, kind: DateTimeKind) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, calendar: Globalization.Calendar) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, millisecond: int) : unit
   (+0 other overloads)
DateTime(year: int, month: int, day: int, hour: int, minute: int, second: int, millisecond: int, kind: DateTimeKind) : unit
   (+0 other overloads)

property DateTime.Now: DateTime

property DateTime.Millisecond: int

property DateTime.Second: int

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More information

Link:	http://fssnip.net/7Px
Posted:	8 years ago
Author:	Fabio Galuppo
Tags:	array , random , shuffle