Re: A sub named ∃

[Steve_p]

I believe that this bug is to blame. There are plans to fix it, but, as of yet, I don't know that there has been any progress towards resolving it.

[vkon]

I suspect you know the situation better than me, but why in this particular case the explanation that
∃!~/\w/
will not suffice?
Perl allows utf8-names from letters of non-English alphabets, although documentation strictly warns against this.

[diotalevi]

/w isn't the pattern for matching the first character in identifiers. I never consider \w when matching that first character. In unicode, the pattern to follow is likely /\A\p{IdFirst}\w*\z/. In ASCII, the pattern is /\A[[:alpha:]_]\w*\z/. The pattern /\^\w+\z/ is always wrong when matching identifiers.

[vkon]

all my concious life any unicode-capable perl matches with \w any unicode letter, and I often match russian letters e.g. 0x0432 with \w.

I never did [[:alpha:]], but did succeeded russian letters matching with \w

[ikegami]

Note: In the following source code,
replace "∃" with the UTF-8 representation of "∃", and
replace "трщь" with the UTF-8 representation of "трщь".

use strict;
use warnings;

no warnings 'redefine';

for (
   [ "Symbol,  use utf8: " => "use utf8; sub ∃    {}" ],
   [ "Symbol,  no  utf8: " => "no  utf8; sub ∃    {}" ],
   [ "Russian, use utf8: " => "use utf8; sub трщ&#11
+00; {}" ],
   [ "Russian, no  utf8: " => "no  utf8; sub трщ&#11
+00; {}" ],
) {
   print $_->[0], eval "$_->[1]; 1" ? "Success\n" : $@;
}

outputs

Symbol,  use utf8: Illegal declaration of anonymous subroutine at (eva
+l 1) line 1.
Symbol,  no  utf8: Illegal declaration of anonymous subroutine at (eva
+l 2) line 1.
Russian, use utf8: Success
Russian, no  utf8: Illegal declaration of anonymous subroutine at (eva
+l 4) line 1.

If the problem is what you say it is, wouldn't use utf8 have no effect on the error?