anchor.diff:    (when (eql key #\Esc)
       (glut:destroy-current-window)))
   
  -(defun gl-info ()
  +(defun gl-info (&key ((:verbose *gl-info-verbose*) nil))
     (glut:display-window (make-instance 'gl-info-window)))
  +
  
positive.code:   (:default-initargs :width 500 :height 500 :title "gl-info.lisp"
                       :mode '(:double :rgba)))
  
  (defmethod glut:display-window :before ((w gl-info-window))
    ;; todo: check for extensions/versions before some of these...
    (format t "GL version: ~a~%" (gl:get* :version))
  
negative.code:                    :max-elements-vertices
                     :compressed-texture-formats
                     :num-compressed-texture-formats
                     :num-program-binary-formats
                     :program-binary-formats
                     :num-shader-binary-formats
                     :shader-binary-formats
                     :shader-compiler
                     :min-map-buffer-alignment
                     :max-texture-buffer-size
                     :max-rectangle-texture-size
                     :num-extensions
  