Regex problems about jison HOT 6 CLOSED

Ok, got it working now - I used

[\\]

instead.

According to http://flex.sourceforge.net/manual/Patterns.html#Patterns, Flex used backslashes for escaping, like Perl/JavaScript. The forward slashes are indeed for positive lookaheads, so it looks like they've been correctly mapped. My guess would be that the backslashes are checked individually, replacing successive pairs of backslashes for one, until the final one is replaced by the character following it - so they all disappear.

Cheers,

Marcus.

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Hey simpl,

I'm surprised about #2 -- I'd expect some tests to fail. I'll adress that and #1.

For #3, the Flex (Bison's scanner generator) syntax is a forward slash (/). I'll probably allow both so people coming from either style aren't thrown off. This is essentially the reason I don't copy the regex directly, because I want to support Flex' syntax too.

Thanks for the report. The regex syntax has been out of mind for a while but obviously needs some updates.

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I just realized that Github ate my backslashes too. Sorry about that.

I'm trying the forward slashes now, but again it doesn't appear to be doing what I want. Forward slashes appear to translate to ?=, i.e. positive lookaheads.

Is it possible to get a double-backslash in the resulting JavaScript regex (i.e. matching a single literal backslash)? If so, could you tell me how.

I think that it would be a good idea to allow both Flex and JavaScript regexes. You could perhaps have a setting somewhere to let the users choose between the two. Also, if you do that, then you might want to mention the version of the regex that is being matched in any error messages.

Thanks,

Marcus.

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When trying to input the following regex:

[']([^\\']+|[\\](\n|.))*?[']        return 'SINGLE_STR';

I get the error:

Error: Parse error on line 80:
...\n|.))*?[']         return 'SINGLE_STR';
-----------------------^
Expecting '|', ')'

Even though it's properly balanced in terms of parentheses.

What I really want to enter is:

'([^\\']+|\\(\n|.))*?'

But as mentioned before, the single quotes don't place nicely.

I don't know if this will be useful to you or not.

Cheers,

Marcus.

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These should be adressed as of v0.2.9. Try your original quotes and backslash regex again, though quotes need a slash in front.

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Thanks for fixing this.

Will let you know if there are any more problems.

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