cxxrtl: use octal encoding of non-printables. #4567
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"\x0a" is a perfectly valid escape sequence, but unfortunately "\x0ac"
is equivalent to "\xac", and not "\x0a" "c" as we might expect --- *any*
number of hexadecimal characters after the "\x" is accepted. This can be
hit pretty easily if a newline is present in a format string.
"\x{...}" syntax is only available as of C++23, so use octal format
instead; a maximum of 3 digits following the backslash is accepted.
The alternative would be to render every escape like `" "\x0a" "`, but
it seems more effort that way.
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Oh oops, I could swear I've fixed this--I remember making a poll recently where basically nobody got it right. (Including me, evidently. I have no idea what that was about then...) Thanks for fixing this! |
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Oh, I see, you're applying the change in commit 43ddd89 to |
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Oh! Yeah, I didn't even see that either; amusing that we ended up writing almost exactly the same thing — but that one looks subtly wrong? The low and middle parts only have two significant bits each ( |
Oh. <.<
Please do. <.< (What an embarrassing mistake...) |
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Hehehe, nah, very easy to do. (Just thinking about "3 bits" and I nearly wrote the exact same.) I did a bunch of manual tests just to make sure I wasn't making a subtly incorrect thing even subtly-er worse; for a bit I was outputting absolute garbage due to signed integer behaviour <_> |
"\x0a"is a perfectly valid escape sequence, but unfortunately"\x0ac"is equivalent to"\xac", and not"\x0a" "c"as we might expect --- any number of hexadecimal characters after the\xis accepted. This can be hit pretty easily if a newline is present in a format string."\x{...}"syntax is only available as of C++23, so use octal format instead; a maximum of 3 digits following the backslash is accepted.The alternative would be to render every escape like
" "\x0a" ", but it seems more effort that way.cc @whitequark.