(* lecture 10: more data types; 

datatype Gender = Male | Female;

(* Produces the cost of a haircut for a person of the given gender and age.
   Kids' under 10 haircuts are $10; for adults, men cost $18.25 and women cost $36.50. *)
fun haircutPrice(age, gender) = 
		if age < 10 then 10.00
		else 18.25 * (case gender of
				Male => 1.0
			|	Female => 2.0);


(* Coffee : type, caffeinated?
   Wine   : label, year
   Beer   : brewery name
   Water  : needs no parameters *)
datatype Beverage = 
    Water
|   Coffee of string * bool
|   Wine of string * int
|   Beer of string;

(* Produces cafe's price for the given drink. *)
fun price(Water) = 1.50
|   price(Coffee(type, caf)) = if caf then 3.00
                               else 3.50
|   price(Wine(label, year)) = if year < 2009
                               then 30.0 else 10.0
|   price(Beer(_)) = 4.00;


(* A type to represent binary search trees of integers. *)
datatype IntTree = Empty
	| Node of int * IntTree * IntTree;

(* Adds the given value to the tree in order.
   Produces/returns the new state of the tree node after the add. *)
fun add(Empty, value) = Node(value, Empty, Empty)
|	add(Node(data, left, right), value) =
		if value < data
		then Node(data, add(left, value), right)
		else Node(data, left, add(right, value));

(* Produces the height of the given tree.
   An Empty tree has a height of 0. *)
fun height(Empty) = 0
|	height(Node(_, left, right)) =
		1 + Int.max(height(left), height(right));