(* Simple expressions *)
34 + 8;;

27.0 +. 9.4;;

"hello";;

(* Hello, World! *)
print_string "Hello, world!\n";;

(* Basic Types *)
20.3;;

let answer = 42;;

(answer < 50);;

"Ravi";;

1 + "hello";;

2.0 +. 4;;

(* Value Creation 1: Global Let *)
let a = 42;;

a * 6;;

let i = 20;;

let a = 10;;

a * 2;;

(* Value Creation 2: Local Variables *)
let i = 10;;

let a = 20;;

let i = a + a
in i * a;;

i * a;;

(* Value Creation 3: Function Definition *)
let i = 10;;

let f n = i + 10;;

f i;;

let i = 100;;

f i;;

(* Alternate Syntax *)
let f n = n + 10 ;;

f 20;;

let f = fun n -> n + 10 ;;

f 20;;

let g x y = x + y ;;

g 5 6 ;;

let g = fun x y -> x + y ;;

g 5 6 ;;

let g = fun x -> fun y -> x + y;; 

g 5 6 ;;

(* Function calls *)
let i = 10;;

let f n = i + 10;;

f i;;

let i = 100;;

f i;;

(* Anonymous Functions *)
(fun n -> n + 10) 20;;

(fun x y -> x + y) 3 4;;

(* Functions as Parameters *)
(fun x y -> x y) (fun x -> x + 5) 4;;

let thrice f x = f(f(f x));;

let inc n = n + 1;;

thrice inc 4 ;;

let inc3 = thrice inc;;

inc3 4;;

(* Problem 1 *)
let x = 20;;

let f = fun x -> x + 1 ;;

let y = f 30;;

print_int x;;

(* Function Types *)
let inc x = x + 1;;

inc 5;;

inc 2.4;;

(* Functions with Multiple Parameters *)
let triangle a b = a * a + b * b ;;

triangle 3 4;;

let t3 = triangle 3;;

t3 4;;

(* Local Let *)
let triangle a b =
  let asq = a * a in
  let bsq = b * b in
    asq + bsq;;

(let x = 10 in x) + (let x = 20 in x);;

(* Scoping Question *)
let x = 27;;

let foo x =
  let x = 5 in
    (fun x -> print_int x) 10;;

foo 12;;

(* Tuples *)
let t = 2,3 ;;

let t2 = (3,42) ;;

let t3 = (2, "string", true, fun x -> x + x);;

let t4 = (1,(2,(3,4))) ;;

(* Pulling tuples apart *)
let t3 = (2, "string", true, fun x -> x + x);;

let (a,b,c,d) = t3;;

let (n,_,_,f) = t3 in f n;;

(* Pattern Matching *)
let iszero n =
  match n with
    | 0 -> "it's zero"
    | 1 -> "it's one"
    | _ -> "not zero or one";;

iszero 1;;

(* Alternate Syntax *)
let iszero = function
    0 -> "it's zero"
  | 1 -> "it's one"
  | _ -> "not zero or one";;

let getfirst = function
    (a,b,c) -> a ;;

getfirst (1,2,3) ;;

getfirst ("Test",5,2.73) ;;

(* Variable Creation Method 4: Matching *)
let inctup a =
  match a with
    | (0,y) -> y,1
    | (x,y) -> x+1,y+1 ;;

inctup (2,3) ;;

inctup (0,3);;

(* List Examples *)
[] ;;

let empty = [] ;;

let single = [1] ;;

let rlist = [2.3; 4.2; 5.3] ;;

let badlist = [3; 4; 3.14159] ;;

(* Problem 2 *)

[2;3;4;6];;

[2,3 ; 4,5 ; 6,7];;

[2.3, 4; 3.2, 5; 6, 7.2];;

[["hi"; "there"]; ["how"]; []; ["goezit"]];;

(* Adding to lists *)
let l1 = [3;6;9];;

let l2 = [4;7;10];;

5 :: l1;;

10 :: 20 :: l2;;

l1 @ l2;;

(* Pattern Matching with Lists *)
let getfirst l =
  match l with
    | [] -> 0
    | x::xs -> x;;

getfirst [];;

getfirst [3;4;5];;

(* Polymorphic List Functions *)
let isempty l =
  match l with
    | [] -> "empty"
    | _ -> "nonempty";;

isempty ["hi";"there"];;

isempty [2;3];;

(* Combining Types *)
let e1 = [ [20;30]; [10;5;2]; [3;6]; []];;

let e2 = [2,3; 4,5; 6,7];;

(* If *)
if (3 < 5) then print_string "hi!\n"

let x = 10;;

let y = (if x < 10 then 40 else 50) * 2 ;;

(* Sequencing *)
(print_string "Bye\n"; 25);;

let a = 3
let b = a + 2;;