anchor.diff:      ;
   
   verb
  -    : varOrIRIref | A
  +    : varOrIRI | A
       ;    
   
   objectList
  
positive.code:     : var | graphTerm
      ;
  
  varOrIRIref
      : var | iri
      ;
  
  
negative.code:     ;
  
  describeQuery
      : DESCRIBE (varOrIRI+ | ASTERISK) datasetClause* whereClause? solutionModifier
      ;
  
  askQuery
  