re_replace: backslash escaping changed #24
Comments
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@kamahen, was this change intended? I found some compatibility page at https://www.regular-expressions.info/replacebackref.html, which claims that \1-\9 is supported by most major languages (doesn't talk about \0). It is deprecated in Perl. |
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library(pcre) does not use PCRE2's replacement API; it continues to do things in the same way as the old code that used PCRE1. The handling of \1-\9 is in Prolog code, in particular Line 608 in 6200023 I did make some changes in how replacements are handled - in particular, there were some bugs that I fixed (e.g., see Issue #9 and Issue #5). There was also a problem with "\" escaping ... this seems to be the relevant commit: 49e811c ... it's possible that I don't have enough test cases, so I'll put together a PR that adds something like what @spl has pointed out and - if it indicates a bug rather than a bug that's been fixed - I'll come up with a fix. But it could take me a few days to do this (I'm preoccupied with some other things) -- I hope that's OK. |
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No problem. The last example I wrote works before and after, so I've already changed our code to use that. Thanks! |
In 6c70176...fe4775d (which I derived from SWI-Prolog/swipl-devel@4c14056), something change in how
re_replaceworked. I think it has to do with the backslash escaping.Before the above commit range, this worked:
?- re_replace('[|]'/g, '\\\\0', '|', Out). Out = "\\|".After the above commit range,
Outchanged:?- re_replace('[|]'/g, '\\\\0', '|', Out). Out = "\\0".In order to get back to the first
Out, I can add\\:?- re_replace('[|]'/g, '\\\\\\0', '|', Out). Out = "\\|".Fortunately, I can also use
$0instead of\0, which works both before and after the above commit range:?- re_replace('[|]'/g, '\\$0', '|', Out). Out = "\\|".The text was updated successfully, but these errors were encountered: