#light 

module Five

printfn "%A" (1 + 2 * 3)                       // p. 66
printfn "%A" ("H"," ", 'H')                    // p. 68  
printfn "%A" (-1 + 2 - 3 * 4 / 5 % 6)        
printfn "%A" (-1.0+2.0-3.0*4.0/5.0)           
printfn "%A" ("bibity" + "bobity" + "boo")  
printfn "%A" (2<3, 1.0<=1.0, 'd'>'c',
                                "abce">"abd")  // p. 69 
printfn "%A" (1<2 || 3>4, 1<2 && not (3<4), 
                          true || 1/0=0)
printfn "%A" (if 1<2 then 'x' else 'y')        // p. 70
printfn "%A" (if 1>2 then 34 else 56)
printfn "%A" ((if 1<2 then 34 else 56) + 1)
printfn "%A" (if 1<2 then print_any 34)        
  // F#, 'if' needs unit type
printfn "%A" (float(123),floor(3.6),
              floor 3.6, string 'a')           // p. 72 
printfn "%A" (ceil 3.6, round 3.6, 
              truncate 3.6, int 'a', char 97)
let x = 1 + 2 * 3                              // p. 73
let y = if x = 7 then 1.0 else 2.0
let fred = 23
//let fred = true                              
   // error, cannot redefine top-level 
(let fred = true 
 printfn "%A" (x, y, fred)                     
  // fred has local scope
)
printfn "%A" (fred)                            
  // uses top-level fred            
let barney = (1+2, 3.0*4.0, "brown")           // p. 74 
let point1 = ("red", (300, 200))
let _, b, _ = barney                           // p. 75 
printfn "%A" b
let xx = (1,2,3)
let (_, (c,_)) = point1
printfn "%A" c
match point1 with 
  | (_, (cc,_)) -> printfn "%A" (cc)
printfn "%A" ([1;2;3])                         
printfn "%A" ([1.0; 2.0])
printfn "%A" ([true])
let x1 = [1;2;3]
printfn "%A" x1.IsEmpty                       // p. 76  
printfn "%A" ([1;2;3]@[4;5;6])
let x2 = 'c' :: [];
let y2 = 'b' :: x2                            // p. 77 
let z2 = 'a' :: y2
printfn "%A" (x2, y2, z2)
printfn "%A" (x1, x1.Head, x1.Tail, 
          x1.Tail.Tail, x1.Tail.Tail.Tail)
let explode (s : string)                      // p. 78 
      = s.ToCharArray() |> Array.to_list
printfn "%A" (explode "fred")
let firstChar s = (explode s).Head
printfn "%A" (firstChar "abc")
let quot (a,b) = a/b
printfn "%A" (quot (6,2))                     // p. 79
let pair = (6,2)
printfn "%A" (quot pair)
let rec fact n =
   if n=0 then 1
   else n*fact(n-1)
printfn "%A" (fact 5)
let rec listsum (x : int list) =
   if x.IsEmpty then 0                       // p. 80
   else x.Head + listsum x.Tail 
printfn "%A" (listsum [1;2;3;4;5])
let rec length (x : 'a list) =
   if x.IsEmpty then 0
   else 1 + length x.Tail
printfn "%A" (length [true; false; true])
printfn "%A" (length [4.0; 3.0; 2.0; 1.0])
let rec badlength (x : 'a list) =
    if x=[] then 0
    else 1 + length x.Tail
printfn "%A" (badlength [true; false; true])
printfn "%A" 
            (badlength [4.0; 3.0; 2.0; 1.0]) // p. 81
let rec reverse (L : 'a list) =
   if L.IsEmpty then []
   else reverse(L.Tail) @ [L.Head]
printfn "%A" (reverse [1;2;3])
let prod (a,b) = a*b 
let prodf (a:float, b:float) : float = a * b