(* 15-212, Spring 2011 *)
(* Michael Erdmann *)
(* Code for Lecture 1: Evaluation and Typing *)

(* Integers *)
~1 : int; (* NOT -1 *)
4 : int;
~3+2 : int;
5 div 2 : int;

(* Reals *)
3.14 : real;
5.0 / 2.0 : real; (* NOT 5 / 2 *)

(* Booleans *)
true : bool;
false : bool;

if 0 = 0 then 1.0 else 2.0 : real;
if true then 4.0 else 1.0/0.0: real;

(* Typing and Evaluation *)
(* Some ill-typed expressions *)
(*
2.0 + 1;
if true then 1 else 2.0;
true + 0;
*)

(* Some well-typed expressions without a value *)
(*
1 div 0;
if 1 div 0 = 0 then true else false;
if false then 4 else 1 div 0;
*)