anchor.diff:      ;
       
   quads
  -    : triplesTemplate? ( quadsNotTriples triplesTemplate? )*
  +    : triplesTemplate? (quadsNotTriples triplesTemplate?)*
       ;
       
   quadsNotTriples
  
positive.code: options {
  tokenVocab=Sparql; // reuse token types
  ASTLabelType=CommonTree; // $label will have type CommonTree
  //output=template;
  }
  
  @header {
  
negative.code:     ;
  
  varOrTerm
      : var | graphTerm | BLANK_NODE
      ;
  
  varOrIRIref
  