# 4 + 1
  ;;
- : int = 5
# 4;;
- : int = 4
# 1;;
- : int = 1
# "Hello world";;
- : string = "Hello world"
# "Hello" ^ " world";;
- : string = "Hello world"
# 3.14;;
- : float = 3.14
# false;;
- : bool = false
# true;;
- : bool = true
# 'a';;
- : char = 'a'
# 'ab';;
Error: Syntax error
# (1 + (2 + 3''
Error: Invalid literal 3''
# (1 + (2 + 3;;
Error: Syntax error: ')' expected
Line 1, characters 5-6:   This '(' might be unmatched
# 4 + "Hello";;
Error: This expression has type string but an expression was expected of type
         int
# 4 + 'Hello';;
Error: Syntax error
# 42 / 0;;
Exception: Division_by_zero.
# try 42 / 0 with Division_by_zero -> -1;;
- : int = -1
# try 42 / 0 with e -> "Hello";;
Error: This expression has type string but an expression was expected of type
         int
# if true then 5 else "Hello";;
Error: This expression has type string but an expression was expected of type
         int
# if 5 > 0 then 5 else 0;;
- : int = 5
# if 5 > 0 then true else false;;
- : bool = true
# 5 > 0;;
- : bool = true
# let five_gt_zero = 5 > 0;;
val five_gt_zero : bool = true
# five_gt_zero;;
- : bool = true
# x;;
Error: Unbound value x
# let x = 1 + 2 in x + 3;;
- : int = 6
# x;;
Error: Unbound value x
# (let x = 1 + 2 in x + 3) + (let x = 4 + 5 in x + 6);;
- : int = 21
# let x = 1 in (let x = 2 in x) + x;;
- : int = 3

-- 
Stefan Muller
Gladwin Development Chair Assistant Professor
Computer Science Department
Illinois Institute of Technology