anchor.diff:      
   SEPARATOR : ('S'|'s')('E'|'e')('P'|'p')('A'|'a')('R'|'r')('A'|'a')('T'|'t')('O'|'o')('R'|'r');
   
  -IRI_REF
  +IRIREF
       : '<' (~('<' | '>' | '"' | OPEN_CURLY_BRACE | CLOSE_CURLY_BRACE | PIPE | INVERSE | '`' | '\\' | '\u0000'..'\u0020'))* '>'
       ;
   
  
positive.code: INTEGER : DIGIT+;
  
  DECIMAL
      : DIGIT+ DOT DIGIT*
      | DOT DIGIT+
      ;
  
  
negative.code: 
  fragment
  ECHAR : '\\' ('t' | 'b' | 'n' | 'r' | 'f' | '\\' | '"' | '\'');
  
  fragment
  PN_CHARS_BASE
  