anchor.diff:  WS : (' ' | '\t' | NL) -> skip;
   COMMENT: '/*' .*? '*/' -> skip;
   LINE_COMMENT : '//' ~[\r\n]* NL? -> skip;
  -STRING : '"' ('\\"' | ~'"')* '"';
  +DSTRING : '"' ('\\"' | ~'"')* '"';
  +SSTRING : '\'' ('\\\'' | ~'\'')* '\'';
   URL : 'url(' ~[)]* ')';
   COMMA : ',';
   SEMICOLON: ';';
  
positive.code: binomial: integer IDENTIFIER (PLUS DIGITS)?;
  
  //attribute_selector: parser.cpp:517
  attribute_selector: LSQBRACKET type_selector ((TILDE | PIPE | STAR | CARET | DOLLAR)? EQUALS (STRING | IDENTIFIER))? RSQBRACKET;
  
  type_selector: namespace_prefix? IDENTIFIER;
  
  
negative.code:                     ((EVEN_KW | ODD_KW)
                       | binomial
                       | IDENTIFIER
                       | string
                      )?
                    RPAREN
                   )
  