On 2023-04-06 08:45, demerphq wrote:
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.
$ 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
