anchor.diff:      }
   ;
   
  +
   mapping_var returns [ClawMappingVar mappingVar]:
       lhs=IDENTIFIER '/' rhs=IDENTIFIER
       {
         $mappingVar = new ClawMappingVar($lhs.text, $rhs.text);
       }
  -  | i=IDENTIFIER { $mappingVar = new ClawMappingVar($i.text, $i.text); }
  +  | i=IDENTIFIER
  +    {
  +      $mappingVar = new ClawMappingVar($i.text, $i.text);
  +    }
   ;
  +
   
   mapping_var_list[List<ClawMappingVar> vars]:
        mv=mapping_var { $vars.add($mv.mappingVar); }
  
positive.code:     '(' ids_list[indexes] ')' { $language.setIndexes(indexes); }
    | /* empty */
  ;
  
  range_option returns [ClawRange r]
    @init{
  
negative.code: ;
  
  
  mapping_option returns [ClawMapping mapping]
    @init{
      $mapping = new ClawMapping();
      List<ClawMappingVar> listMapped = new ArrayList<ClawMappingVar>();
      List<ClawMappingVar> listMapping = new ArrayList<ClawMappingVar>();
      $mapping.setMappedVariables(listMapped);
      $mapping.setMappingVariables(listMapping);
    }
    :
      MAP '(' mapping_var_list[listMapped] ':' mapping_var_list[listMapping] ')'
  ;
  
  
  /*----------------------------------------------------------------------------
   * LEXER RULES
  