Add compatibility with rfc2822 comments #733
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Finomnis
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| "Tue, 20 Jan 2015 17:35:20 -0800 ( (UTC ) (\\( (a)\\(( \\t ) ) \\\\( \\) ))", | ||
| Ok("Tue, 20 Jan 2015 17:35:20 -0800"), | ||
| ), // complex trailing comment | ||
| ("Tue, 20 Jan 2015 17:35:20 -0800 (UTC\\)", Err(TOO_LONG)), // incorrect comment, not enough closing parentheses |
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It seems like TOO_SHORT is more optimal in this case (admittedly obscure) - but it seems like actually getting TOO_SHORT at this stage might not be trivial, unless we early return from scan::comment_2822. Potentially the logic could be that if there is at least one ( then it makes sense to early return the TOO_SHORT if it is never closed. Alternatively, the parser could be more permissive and just remove all the comment characters and return the parsed date if the rest is in the correct format - let me know what your thoughts are here?
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I had the same thought, but for one, it's indeed not trivial to change that; and further, it's not completely clear. Technically "Tue, 20 Jan 2015 17:35:20 -0800 (" could be both too short or too long. "Tue, 20 Jan 2015 17:35:20 -0800 x", for example, is definitely too long, so one could argue that the first one is also a valid string plus " (". So I'd argue that "a comment" is everything that parses as a comment, and "too long" is everything attached to the timestamp that doesn't parse as a comment. Which includes " (".
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I don't think just accepting everything is the right choice, at least not with your current code structure. parse.rs just parses a single rfc2822 datetime string, and the way it is currently written means it could be used as a part of a more complex parser. So I wouldn't allow just everything, otherwise I think the entire TOO_LONG value would be pointless and we could simply accept all the strings that start with a valid rfc2822 datetime.
If you want me to change something, then what I would agree with most is to short-circuit TOO_SHORT. But that also wouldn't be true the way the code is written right now, because the parse_rfc2822 conceptually is supposed to attempt to parse a rfc2822 datetime string + return the leftover input that wasn't part of the rfc2822 datetime. And it does exactly that in the case of "Tue, 20 Jan 2015 17:35:20 -0800 (", because "Tue, 20 Jan 2015 17:35:20 -0800" is a valid rfc2822 string and " (" is a valid rest. It just wasn't able to consume " (", which is totally valid.
So if we want to change something, it must be somewhere in the method parse_internal. And this one currently is written so that it always returns TOO_LONG whenever any tokens are left over from parsing. So I'm not sure how TOO_SHORT would conceptually fit the current code structure.
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Thanks @Finomnis - really good point about the rfc2822 item being able to be reused within other formats, we definitely shouldn't break that so it looks like it is best to leave it as is.
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@esheppa Rebased to fix merge conflict in |
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Thanks @Finomnis |
Fixes #732.