Re: bug#60690: -P '\d' in GNU and git grep
- From
Paul Eggert <eggert@cs.ucla.edu>
- Date
- Apr 7, 2023, 16:48 UTC
- Message-ID
- <767d3617-e35a-a693-6ec8-f65421c68e5f@cs.ucla.edu>
- In-Reply-To
- <CANgJU+XoyptS8NU+f6uMLrKjQakv=iN2c4DQydVaBVH3dK3s-w@mail.gmail.com>
On 2023-04-06 08:45, demerphq wrote:
Show 13 quoted lines
>> Although this causes pcre2grep to mishandle Unicode characters: >> >> $ echo 'Ævar' | pcre2grep '[Ssß]' >> Ævar >> >> it mimics Perl 5.36: >> >> $ echo 'Ævar' | perl -ne 'print $_ if /[Ssß]/' >> Ævar >> >> so this seems to be what Perl users expect, despite its infelicities. > Actually no, I think you have misunderstood what is happening at the > different layers involved here.
No, I understood what was going on. My point was that Perl users seem to have accepted this behavior, even though it does not match what people would ordinarily expect.
> What you should have done is something like this:
No, for two reasons. First, I'm no Perl expert and so I don't know (and don't particularly want to learn) its complicated Unicode options and calls. Second, /[Ss\x{DF}]/u is hard to read. If I want the S letters of traditional German, I'll write them in the obvious way, as [Ssß]. No doubt Perl will let me do this somehow - but it is telling that none of your examples do it in such a straightforward way.
Show 10 quoted lines
> $ echo 'Ævar' | perl -ne 'utf8::decode($_); print $_ if /[Ss\x{DF}]/u'
> $ echo 'baß' | perl -MEncode -ne 'utf8::decode($_); print
> encode_utf8($_) if /[Ss\x{DF}]/u'
> baß
> $ echo 'Ævar' | perl -MEncode -ne 'utf8::decode($_); print
> encode_utf8($_) if /[Ss\x{C6}]/u'
> Ævar
> $ echo 'Ævar' | perl -MEncode -ne 'utf8::decode($_); print
> encode_utf8($_) if /[Ss\x{e6}]/ui'
> Ævar