anchor.diff:      ;
   
   moduleRevision:
  -    'REVISION' stringValue
  +    ('REVISION' stringValue)?
       'DESCRIPTION' stringValue
       ;
   
  
positive.code:     ;
  
  objectIdentifierValue :
      '{' objIdComponentsList '}'
      ;
  
  objIdComponentsList :
      (objIdComponents ','? )+
      ;
  
  objIdComponents 
  
negative.code:     | name='AUGMENTS' augments
      | name='WRITE-SYNTAX' type
      | name='PRODUCT-RELEASE' stringValue
      | name='CREATION-REQUIRES' groups
      | name='DISPLAY-HINT' stringValue
      | name='REFERENCE' stringValue
  ;
  