let projectEulerProblemOne = [1 .. 999] |> List.filter(fun x -> x % 3 = 0 || x % 5 = 0) |> List.sum

type Person = { Name : string; Gender : string }

let alice = { Name = "Alice"; Gender = "Female" }
let bob = { Name = "Bob"; Gender = "Male" }

let femaleOrMale p =
    match p with
    | { Gender = "Female" } -> p.Name + " is female."
    | { Gender = "Male" } -> p.Name + " is male."
    | _ -> "???"

type SafeStringNumbers() =

    member this.Bind(x, f) =
        match System.Int32.TryParse(x) with 
        | (true, v) -> f v
        | _ -> f 0

    member this.Return(x) =
        x

let safeStringNumbers = new SafeStringNumbers()

let v1 = safeStringNumbers {
    let! a = "1"
    let! b = "2"
    let! c = "3"
    return a + b + c
}

let v2 = safeStringNumbers {
    let! a = "1"
    let! b = "foo"
    let! c = "3"
    return a + b + c
}

let sq = seq {
    yield 1
    yield! seq { 2 .. 6 }
    yield 7
    yield! seq [8; 9; 10]
}

let count = Seq.length sq
let list = List.ofSeq sq

let evens = [2 .. 2 .. 10]
let odds = [for i in evens -> i - 1]
let fizzBuzzNumbers = [for i in 1 .. 100 do if i % 3 = 0 && i % 5 = 0 then yield i]

printfn "%A" evens
printfn "%A" odds
printfn "%A" fizzBuzzNumbers

let getSign x = if x > 0 then "+" elif x < 0 then "-" else "0"
let foo = [-3..3] |> List.map getSign |> String.concat(" ")

printfn "%s" foo

let areEqualsIgnoreCase (s : string * string) = 
    match s with 
    | (s1, s2) when s1.ToUpper() = s2.ToUpper() -> true
    | _ -> false
    
printfn "%b" (areEqualsIgnoreCase ("Hello", "hello"))
printfn "%b" (areEqualsIgnoreCase ("hello", "HELLO"))
printfn "%b" (areEqualsIgnoreCase ("hello", "ello"))

let detectType v =
    match box v with
    | :? int -> printfn "int"
    | :? string -> printfn "string"
    | _ -> printfn "?"

detectType 1
detectType "1"
detectType 1.0

let tryParseInt s = 
   try
      let i = System.Int32.Parse s
      Some i
   with _ -> None

let v1 = tryParseInt "1"
printfn "%O" v1
printfn "%O" v1.Value
printfn "%O" v1.IsSome
printfn "%O" v1.IsNone

printfn ""

let v2 = tryParseInt "?"
printfn "%O" v2
printfn "%O" v2.IsSome
printfn "%O" v2.IsNone

[for i in 1 .. 30 -> if i % 3 = 0 && i % 5 = 0 then "FizzBuzz" elif i % 3 = 0 then "Fizz" elif i % 5 = 0 then "Buzz" else i.ToString()] |> List.map(fun v -> printfn "%s" v)

let add n x = x + n
let times n x = x * n

let f1 = add 1 >> times 2
let f2 = add 1 << times 2

printfn "%i" (f1 2) // (2+1)*2
printfn "%i" (f2 2) // 2*2+1

let add x y = x + y

let add1 = add 1
let add2 = add 2
let add3 = add 3
let add1and2and3 = add1 >> add2 >> add3

printfn "%i" (0 |> add1and2and3)

let add x y = x + y


let add1 = add 1
let add2 = add 2
let add3 = add 3


printfn "%i" (add1 1)
printfn "%i" (add2 1)
printfn "%i" (add3 1)

printfn "%*s" 5 "*"
printfn "%*s" 6 "***"
printfn "%*s" 7 "*****"
printfn "%*s" 8 "*******"
printfn "%*s" 9 "*********"

let (|Int|_|) str = match System.Int32.TryParse(str) with | (true, int) -> Some(int) | _ -> None
let (|Bool|_|) str = match System.Boolean.TryParse(str) with | (true, bool) -> Some(bool) | _ -> None

let parse s = 
    match s with
    | Bool b -> printfn "%-10s%b" "Bool" b  
    | Int i -> printfn "%-10s%i" "Int" i                      
    | _ -> printfn "%-10s%O" "???" s

parse "0"
parse "1"
parse "2"
parse "3"
parse "123"
parse "-123"
parse "True"
parse "true"
parse "False"
parse "False"
parse "hello"