code: def t_php_START_HEREDOC(t):
      r'<<<[ \t]*(?P<label>[A-Za-z_][\w_]*)\n'
      t.lexer.lineno += t.value.count("\n")
      t.lexer.push_state('heredoc')
      t.lexer.heredoc_label = t.lexer.lexmatch.group('label')
      return f t_php_START_HEREDOC(t):
      r'<<<[ \t]*(?P<label>[A-Za-z_][\w_]*)\n'
      t.lexer.lineno += t.value.count("\n")
      t.lexer.push_state('heredoc')
      t.lexer.heredoc_label = t.lexer.lexmatch.group('label')
      return t
docs: r'<<<[ \t]*(?P<label>[A-Za-z_][\w_]*)\n