On 2023-04-03 20:30, Jim Meyering wrote:
have you seen justification (other than for compatibility with some other tool or language) for allowing \d to match non-ASCII by default, in spite of the risks?
In the example Ævar supplied in <https://bugs.gnu.org/60690>, my impression was that it was better when \d matched non-ASCII digits. That is, in a UTF-8 locale it's better when \d finds matches in these lines:
> git-gui/po/ja.po:"- 第１行: 何をしたか、を１行で要約。\n" > git-gui/po/ja.po:"- 第２行: 空白\n"
because they contain the Japanese digits "１" and "２". This was the only example I recall being given.
Also, I find it odd that grep -P '^[\w\d]*$' matches lines containing any sort of Arabic word characters, but it rejects lines containing Arabic digits like "٣" that are perfectly reasonable in Arabic-language text. I also find it odd that [\d] and [[:digit:]] mean different things.
There are arguments on the other side, otherwise we wouldn't be having this discussion. And it's true that grep -P '\d' formerly rejected Arabic digits (though it's also true that grep -P '\w' formerly rejected Arabic letters...). Still, the cure's oddness and incompatibility with Git, Perl, etc. appears to me to be worse than the disease of dealing with grep -P invocations that need to use [0-9] or LC_ALL="C" anyway if they want to be portable to any program other than GNU grep.
