anchor.diff:  ;(in-package #:cl-foo)
   
   (require :sdl2)
  +
  +(defconstant +width+ 1280)
  +(defconstant +height+ 720)
   
   (defun main-loop ()
     (defun keydown-actions (scancode)
  
positive.code: 
    (defun init ()
      (gl:enable :depth-test)
      (gl:viewport 0 0 1280 720)
      (gl:matrix-mode :projection)
      (gl:ortho -2 2 -2 2 -2 2)
      (gl:matrix-mode :modelview)
  
negative.code:     (gl:clear :color-buffer :depth-buffer))
  
    (sdl2:with-init (:everything)
      (sdl2:with-window (win :w +width+ :h +height+ :flags '(:shown :opengl))
        (sdl2:with-gl-context (gl-context win)
          (sdl2:gl-make-current win gl-context)
          (init)
  