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Postings from July 2017
On Tuesday 04 July 2017 03:12:19 yves orton via RT wrote:
> On 4 July 2017 at 12:04, <pali@cpan.org> wrote:
> > On Tuesday 04 July 2017 11:22:42 demerphq wrote:
> >> No. This is a myth. Plain and simply a myth.
> >>
> >> People have a hard time accepting it, but the utf8 flag tells parts of
> >> the internals to use different rules for certain operations, when set
> >> those rules are Unicode. When the flag is not set the default rules
> >> are derived from ASCII.
> >>
> >> You can see the difference in the following:
> >>
> >> "ba\x{DF}"=~/ss/i;
> >
> > $ perl -E 'say "matched" if "ba\x{DF}"=~/ss/i;'
> > matched
> >
> >> "ba\N{U+DF}"=~/ss/i;
> >
> > $ perl -E 'say "matched" if "ba\N{U+DF}"=~/ss/i;'
> > matched
>
> -E is not -e.
>
> -E is enabling a pragma which changes the default behavior.
>
> However it is *PRAGMA*. It is NOT the normal behavior of Perl.
Ah, right. I forgot that -E enables feature unicode_strings which
basically means that both examples were equivalent.
Default behavior is a bit unpredicable as it is affected by the
infamous Unicode Bug.
my $str1 = "\x{DF}";
my $str2 = "\N{U+DF}";
my $str3 = "\x{100}";
"ba$str1" =~ /ss/i;
"ba$str2" =~ /ss/i;
"ba$str1$str3" =~ /ss/i;
To make it predicable either /aa or /u modifiers should be already
used... It will prevent problems
"ba$str1" =~ /ss/aai;
"ba$str2" =~ /ss/aai;
"ba$str1$str3" =~ /ss/aai;
"ba$str1" =~ /ss/ui;
"ba$str2" =~ /ss/ui;
"ba$str1$str3" =~ /ss/ui;
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