anchor.diff:  (defclass  mf-matrix4d (x3d-array-field)
     ()
     (:documentation "
  -ISO/IEC 19775-1:2008
  +ISO/IEC 19775-1:2008 (SEE NOTICE.TXT)
   
   5.3.10 SFMatrix4d and MFMatrix4d
   
  
positive.code: (defclass  sf-color-rgba (x3d-field)
    ()
    (:documentation "
  ISO/IEC 19775-1:2008
  
  5.3.3 SFColorRGBA and MFColorRGBA
  
  
negative.code: (defclass  mf-string (x3d-array-field)
    ()
    (:documentation "
  ISO/IEC 19775-1:2008 (SEE NOTICE.TXT)
  
  5.3.14 SFString and MFString
  
  