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Add support for "|" inside productions #100
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- Seems reasonable to me בתאריך יום ג׳, 4 באוג׳ 2020, 16:45, מאת Philippe Laferrière < notifications@github.com>:…Cleans up the use case where one has many small productions. For example, @pg.production("prod: TOKEN_1") # ... <24 lines> @pg.production("prod: TOKEN_26") def func(p): pass Would be simplified to @pg.production("prod: TOKEN_1 | ... | TOKEN_26") def func(p): pass More specifically, I need this right now, as I need to accept (and throwaway) all tokens until I see a newline. I'd be happy to submit a PR if you guys think it's a valuable feature to have. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#100>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAAGBHFK3T77XN5C6X72T3R7BXOXANCNFSM4PUZBPEQ> .
We have a production rule
bin_expr : expr | exprwhere | stands for BitOr, which was fine with 0.7.7 but broken on 0.7.8. It seems to be caused by this change. I wonder if there's a way to get around? Some kind of escaping or else?Perhaps \ escapes it? If not then add a lexer rule to match | to VERTICLE_PIPE or similar and use that? @nobodxbodon
@leocornelius thanks for the suggestion. Just tried this test case and it does seem to work:
def test_arithmetic(self): lg = LexerGenerator() lg.add("NUMBER", r"\d+") lg.add("BITOR", r"\|") pg = ParserGenerator(["NUMBER", "BITOR"], precedence=[ ("left", ["BITOR"]), ]) @pg.production("main : expr") def main(p): return p[0] @pg.production("expr : expr BITOR expr") def expr_binop(p): return BoxInt(operator.or_(p[0].getint(), p[2].getint())) @pg.production("expr : NUMBER") def expr_num(p): return BoxInt(int(p[0].getstr())) lexer = lg.build() parser = pg.build() assert parser.parse(lexer.lex("1|8")) == BoxInt(9)
See #101, it should now be fixed :)
Cleans up the use case where one has many small productions. For example,
Would be simplified to
More specifically, I need this right now, as I need to accept (and throwaway) all tokens until I see a newline.
I'd be happy to submit a PR if you guys think it's a valuable feature to have.