Playing with game related functions in clojure

gamefuncs.clj

;; Testing some potential basic game functions

;; moved-by : list list -> list
;; computes a new position by adding an x,y pair to an x,y pair
;; example: (moved-by '(1,1) '(0,1)) -> '(1,2)
(defn moved-by [position amount]
	(map + position amount))

;; test moved-by: (moved-by '(1,1) '(0,1)) -> '(1,2)
(println (= '(1 2) (moved-by '(1,1) '(0,1))))

;; all-moved-by : list list -> list
;; computes a list of positions by adding a list of x,y pairs to a list of x,y 
;; pairs
;; example: (all-moved-by '((1,1) (1,1)) '((1,2) (2,3))) -> ((2,3) (3,4))
(defn all-moved-by [positions amounts]
	(map moved-by positions amounts))

;; test all-moved-by: (all-moved-by '((1,1) (1,1)) '((2,3) (3,4)))
(println (= (all-moved-by '((1,1) (1,1)) '((1,2) (2,3))) '((2,3) (3,4))))

;; make-spatial : -> map
;; initializes and returns a map
;; example: (make-spatial) -> {}
(defn make-spatial [] {:position '(0 0) :velocity '(0 0)})

;;test make-spatial: (make-spatial) -> {}
(println (= (make-spatial) {:position '(0 0) :velocity '(0 0)}))

;; apply-gravity : list -> list
;; increments y component of list by gravity const
;; example: (apply-gravity '(0 0)) -> '(0 1)
(defn apply-gravity [position]
	(list (first position) (+ 1 (last position))))

;;test apply-gravity: (apply-gravity '(0 0)) -> '(0 1)
(println (= (apply-gravity '(0 0)) '(0 1)))

;; apply-forces : spatial -> spatial
;; applies world forces to a spatial, returning a new spatial state
;; example: (apply-forces (make-spatial)) -> {:position '(0 0) :velocity '(0 1)}
(defn apply-forces [spatial]
	(-> spatial
		(assoc :velocity (apply-gravity (:velocity spatial)))))

;; test apply-forces:
;; (apply-forces (make-spatial)) -> {:position '(0 0) :velocity '(0 1)}

(println (= (apply-forces (make-spatial)) {:position '(0 0) :velocity '(0 1)}))

;; move-spatial : map -> map
;; moves the spatial's position by the player's velocity returning new position
;; example: (update-spatial {:position '(0 0) :velocity '(1 1)}) -> '(1 1)
(defn move-spatial [spatial]
	(-> spatial
		(assoc :position (moved-by (:position spatial) (:velocity spatial)))))

(println (=
		(move-spatial {:position '(0 0) :velocity '(1 1)})
		{:position '(1 1) :velocity '(1 1)}))

;; update-spatial : spatial -> spatial
;; makes basic physics updates to a spatial
;; example: (update-spatial (make-spatial)) -> {:velocity '(0 1) :position '(0 1)}
(defn update-spatial [spatial]
	(move-spatial (apply-forces spatial)))

;; test update-spatial: 
;; (update-spatial (make-spatial)) -> {:velocity '(0 1) :position '(0 0)}
(println (= (update-spatial (make-spatial)) {:position '(0 1) :velocity '(0 1)}))

;; step : -> map
;; creates and steps the player one game iteration. eventually should be all entities
;; example: (step) -> {}
(defn step []
	(let [player (make-spatial)]
		(-> player
			update-spatial)))

;; test step
(println (= (step) (update-spatial (make-spatial))))