anchor.diff:  	 do `(define-tessellation-callback ,name ,args))))
   
   (define-tessellation-callbacks
  -  (tess-begin (tesselator (type  tessellation-type)))
  -  (tess-edge-flag (tesselator (flag  %gl:boolean)))
  -  (tess-vertex (tesselator (vertex-data :pointer)))
  -  (tess-end (tesselator))
  +  (tess-begin (tessellator (type  tessellation-type)))
  +  (tess-edge-flag (tessellator (flag  %gl:boolean)))
  +  (tess-vertex (tessellator (vertex-data :pointer)))
  +  (tess-end (tessellator))
     ;;TODO error enum
  -  (tess-error (tesselator (error-number %gl:enum)))  
  +  (tess-error (tessellator (error-number %gl:enum)))  
     ;:TODO add body to convert to arrays
  -  (tess-combine (tesselator (coords :pointer) (vertex-data :pointer) (weight :pointer) (out-data :pointer)))
  -  (tess-begin-data (tesselator (type %gl:enum) (polygon-data :pointer)))
  -  (tess-edge-flag-data (tesselator (flag %gl:boolean) (polygon-data :pointer)))
  -  (tess-end-data (tesselator (polygon-data :pointer)))
  -  (tess-vertex-data (tesselator (vertex-data :pointer) (polygon-data :pointer)))
  +  (tess-combine (tessellator (coords :pointer) (vertex-data :pointer) (weight :pointer) (out-data :pointer)))
  +  (tess-begin-data (tessellator (type %gl:enum) (polygon-data :pointer)))
  +  (tess-edge-flag-data (tessellator (flag %gl:boolean) (polygon-data :pointer)))
  +  (tess-end-data (tessellator (polygon-data :pointer)))
  +  (tess-vertex-data (tessellator (vertex-data :pointer) (polygon-data :pointer)))
     ;;TODO error enum
  -  (tess-error-data (tesselator (error-number %gl:enum) (polygon-data :pointer)))
  -  (tess-combine-data (tesselator (coords :pointer) (vertex-data :pointer) (weight :pointer) (out-data :pointer) (polygon-data :pointer)))
  +  (tess-error-data (tessellator (error-number %gl:enum) (polygon-data :pointer)))
  +  (tess-combine-data (tessellator (coords :pointer) 
  +                                  (vertex-data :pointer) 
  +                                  (weight :pointer) 
  +                                  (out-data :pointer) 
  +                                  (polygon-data :pointer))))
   
   (defclass tessellator ()
     ((glu-tessellator :reader glu-tessellator)))
  
positive.code: #|
  Sample output for input:
   (define-tessellation-callback
  		    tess-begin (tesselator (type  tessellation-type)))
  
   (DEFGENERIC TESS-BEGIN
       (TESSELATOR TYPE))
   (DEFCALLBACK %TESS-BEGIN
      :VOID
      ((TYPE TESSELLATION-TYPE))
  
negative.code:   (tess-begin-contour tess))
  
  (defmethod vertex ((tess tessellator) coords vertex-data)
    (tess-vertex tess coords vertex-data))
  
  (defmethod end-contour ((tess tessellator))
    (tess-end-contour tess))
  