Quasi FRP game using Hy + Pygame

semi-frp-pygame.hy

(import pygame)

;; Impure function - merge dict2 onto dict1
(defn merge_dicts [dict1 dict2]
  (do
   (.update dict1 dict2)
   dict1))


;; Get the base state -  prefered this way instead setv function
(defn init []
  {
       'screen (pygame.display.set_mode [400 300]) ;; Set the window size
       'is_blue True ;; Verify is the actual color is blue
       'limit False  ;; Set to true only if you close the window
       'color_rect [0 128 255] ;; Color of the rect
       'rect_instance (.Rect pygame 30 30 60 60) ;; Rect that will be drawn
      })


;; Return 
(defn update [event state]
  {
   'limit (if (= event.type pygame.QUIT) True False) ;; Verify if the close button was pushed
   'color_rect (if (get state 'is_blue) [0 128 255] [255 100 0]) ;; Verify if the color is blue else return orange color
   'is_blue (if (and (= event.type pygame.KEYDOWN)
                     (= event.key pygame.K_SPACE))
              (not (get state 'is_blue))
              (get state 'is_blue)) ;; Change the color if the key space was typed
   })

(defn draw [state]
  (pygame.draw.rect
   (get state 'screen)
   (get state 'color_rect)
   (get state 'rect_instance))) ;; Draw the rect

(defmain [&rest args]
  (do
   (.init pygame)
   (setv state (init))
   (while (not (get state 'limit))
     (do
      (for [event (pygame.event.get)]
        (draw (merge_dicts state (update event state))))
      (pygame.display.flip)))))