Customized format and print for our kind of tokens
        which gets called in debugging grammar reduce rules

def debug_reduce(self, rule, tokens, parent, i):
        """Customized format and print for our kind of tokens
        which gets called in debugging grammar reduce rules
        """
        prefix = '           '
        if parent and tokens:
            p_token = tokens[parent]
            if hasattr(p_token, 'line'):
                prefix = 'L.%3d.%03d: ' % (p_token.line, p_token.column)
                pass
            pass
        print("%s%s ::= %s" % (prefix, rule[0], ' '.join(rule[1])))