Method test_left_recursive

Lib/test/test_peg_generator/test_pegen.py:428–481

(self)

        )

    def test_left_recursive(self) -> None:
        grammar_source = """
        start: expr NEWLINE
        expr: ('-' term | expr '+' term | term)
        term: NUMBER
        foo: NAME+
        bar: NAME*
        baz: NAME?
        """
        grammar: Grammar = parse_string(grammar_source, GrammarParser)
        parser_class = generate_parser(grammar)
        rules = grammar.rules
        self.assertFalse(rules["start"].left_recursive)
        self.assertTrue(rules["expr"].left_recursive)
        self.assertFalse(rules["term"].left_recursive)
        self.assertFalse(rules["foo"].left_recursive)
        self.assertFalse(rules["bar"].left_recursive)
        self.assertFalse(rules["baz"].left_recursive)
        node = parse_string("1 + 2 + 3\n", parser_class)
        self.assertEqual(
            node,
            [
                [
                    [
                        TokenInfo(
                            NUMBER,
                            string="1",
                            start=(1, 0),
                            end=(1, 1),
                            line="1 + 2 + 3\n",
                        ),
                        TokenInfo(
                            OP, string="+", start=(1, 2), end=(1, 3), line="1 + 2 + 3\n"
                        ),
                        TokenInfo(
                            NUMBER,
                            string="2",
                            start=(1, 4),
                            end=(1, 5),
                            line="1 + 2 + 3\n",
                        ),
                    ],
                    TokenInfo(
                        OP, string="+", start=(1, 6), end=(1, 7), line="1 + 2 + 3\n"
                    ),
                    TokenInfo(
                        NUMBER, string="3", start=(1, 8), end=(1, 9), line="1 + 2 + 3\n"
                    ),
                ],
                TokenInfo(
                    NEWLINE, string="\n", start=(1, 9), end=(1, 10), line="1 + 2 + 3\n"
                ),
            ],
        )

    def test_python_expr(self) -> None:
        grammar = """