gistfile1.ml

module ListPoint = struct
	type point = int list
    let make x y = [x; y]
    let getX p = List.nth p 0
    let getY p = List.nth p 1
    let origin = [0; 0]
	let print p = print_int (getX p); print_string " "; print_int (getY p); print_endline ""
end;;

module Square = struct
	open ListPoint
	type square = point * int
	let opposite_point (p, length) = make ((getX p) + length) ((getY p) + length)
	let make p length = (p, length)	(* must be declared after opposite point, otherwise we can't use make from ListPoint *)
end;;

module AltSquare = struct
	module LP = ListPoint
	type square = LP.point * int
	let make p length = (p, length)
	let opposite_point (p, length) = (LP.make ((LP.getX p) + length) ((LP.getY p) + length))
end;;

module ExtendedSquare = struct
	include Square
	let area (_, length) = length * length
end;;

let my_point = ListPoint.make 10 20 in
let length = 30 in
let my_square = Square.make my_point length in
let opp = Square.opposite_point my_square in
let area = ExtendedSquare.area my_square in
	ListPoint.print opp;
	print_string "Area: "; print_int area; print_newline();

(* SIGNATURES and FUNCTORS  *)

module type POINT_SIG = sig
	type point
	val make: int -> int -> point
	val getX: point -> int
	val getY: point -> int
	val origin: point
	val print: point -> unit
end;;

module ListPointWithSig : POINT_SIG = struct
	type point = int list
	let make x y = [x; y]
	let getX p = List.nth p 0
	let getY p = List.nth p 1
	let origin = [0; 0]
	let print p = print_int (getX p); print_string " "; print_int (getY p)
end;;

module TuplePointWithSig : POINT_SIG = struct
	type point = int * int
	let make x y = (x, y)
	let getX (x, _) = x
	let getY (_, y) = y
	let origin = (0, 0)
	let print (x, y) = print_int x; print_string " "; print_int y
end;;

module SquareFunctor(P: POINT_SIG) = struct
	type square = P.point * int
	let make p length = (p, length)
	let opposite_point (p, length) = P.make ((P.getX p) + length) ((P.getY p) + length)
end;;

module TuplePointSquare = SquareFunctor(TuplePointWithSig);;
module ListPointSquare = SquareFunctor(ListPointWithSig);;

let my_point = TuplePointWithSig.make 10 20 in
let length = 10 in
let my_square = TuplePointSquare.make my_point length in
let opp = TuplePointSquare.opposite_point my_square in
	TuplePointWithSig.print opp