anchor.diff:      | name='OBJECTS' objects
       | name='VARIABLES' variables
       | name='INDEX' index
  -    | name='DEFVAL' '{' value '}'
  +    | name='DEFVAL' '{' defValue '}'
       | name='DISPLAY-HINT' stringValue
       | name='NOTIFICATIONS' notifications
       | name='AUGMENTS' augments
  
positive.code:     ;
  
  sizeConstraint : '(' 'SIZE' '(' constraintElements ')' ')'
      ;
  
  value
  
negative.code: grammar ASN;
  
  moduleDefinition :
      IDENTIFIER ( '{' modulePath? '}' )?
      'DEFINITIONS'
      ASSIGN_OP
      'BEGIN'
      moduleBody
      'END'
      ;
  
  modulePath :
      (IDENTIFIER ('(' NUMBER ')')? NUMBER? )+
      ;
  
  moduleBody :
  