Grammar priorite_declaree;
Lexer
  letter = 'a'..'z';
  digit = '0'..'9';
  identifier = letter(letter|digit)*;
  hexinteger = (digit|'a'..'f')+ Except identifier;
  blank = ' ' | #9 | #10 | #13;
Parser
  Ignored blank;
  p = t*;
  t = identifier | hexinteger;