anchor.diff:  
   (defclass graphics-state ()
     ((bindings)
  -   (program)
  +   (program :accessor program :initform :program)
      (uniform-sets)))
   
   ;;; Uniforms variables, as defined in OpenGL, are slowly-changing values
  
positive.code:   ((shaders :accessor shaders :initarg :shaders :initform nil)
     (uniforms :accessor uniforms :initarg :uniforms :initform nil
               :documentation "Information on uniforms declared within the program shader source.")
     (uset-descriptors)
     (status :accessor status :initarg :status)
     (link-log :accessor link-log :initarg :link-log :initform nil)))
  
  (defmethod gl-finalized-p ((obj shader))
    (slot-boundp obj 'status))
  
negative.code: (defclass renderer ()
    ((buffers :accessor buffers :initform nil)
     (bundles :accessor bundles :initform nil)
     (new-bundles :accessor new-bundles :initform nil)
     (current-state :accessor current-state :initform nil)))
  
  ;;; A simple reference counting protocol for objects that should do some
  ;;; cleanup e.g., release OpenGL resources, when they are no longer used.
  