G'day yulivee07,

My Perl (Mac OS X):

$ perl -v | head -2 | tail -1
This is perl 5, version 24, subversion 0 (v5.24.0) built for darwin-th
+read-multi-2level
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Both 'LATIN SMALL LETTER SHARP S' and 'POUND SIGN' are valid and work for me:

$ perl -C -E 'say "\N{LATIN SMALL LETTER SHARP S}"'
ß
$ perl -C -E 'say "\N{POUND SIGN}"'
£

"It seems AIX perl is unable to find the \N{alpha} character. I am a bit lost here - where does perl usually search for characters like this?"

Without additional code, 'alpha' doesn't work by itself. I get the same error as you:

$ perl -C -E 'say "\N{alpha}"'
Unknown charname 'alpha' at -e line 1, within string
Execution of -e aborted due to compilation errors.
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You can use 'greek:alpha':

$ perl -C -E 'say "\N{greek:alpha}"'
α

I note from the source of t/Encode.t:

use charnames qw(greek);
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That also works for me (see charnames):

$ perl -Mcharnames=greek -C -E 'say "\N{alpha}"'
α

"Can someone provide some debugging tips? "

When running any tests, bear in mind that different versions of Perl support different levels of Unicode:

• 5.20.0: perl5200delta: Unicode 6.3 now supported
• 5.22.0: perl5220delta: Unicode 7.0 (with correction) is now supported
• 5.24.0: perldelta: Unicode 8.0 is now supported
• [If you want Unicode 9.0, either get a developer release >= 5.25.3 or wait for 5.26]

I note from your "perl -V" output, that @INC contains some 5.8.8 paths before 5.20.1 paths. It's possible that old versions of Unicode-related modules are being found first.

Take a look in the code (*.pm, *.t, etc.) shown in your error messages for modules being used, then check which versions you have. For instance, I have

$ perl -E 'use charnames (); say $charnames::VERSION'
1.43
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For Perl 5.20.1, that should be 1.40; for 5.8.8 it should be 1.05. You can go to the latest distribution (http://search.cpan.org/~shay/perl-5.24.1/); use the dropdown list to select 5.20.1, 5.8.8, or any other version; then follow the link to the wanted module (e.g. charnames).

You can test whether your system recognises any named characters by using their codepoints:

$ perl -C -E 'say "\x{3b1} - \x{df} - \x{a3}"'
α - ß - £

Unicode::UCD might provide some useful information. For instance, to check which version of Unicode that a character first appeared in:

$ perl -MUnicode::UCD=charprops_all -E 'say charprops_all("U+$_")->{Ag
+e} for qw{3b1 df a3}'
V1_1
V1_1
V1_1
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For any of the tests above, you could try manipulating @INC first, e.g. move the 5.8.8. paths to the end of the list.

Also, it could be helpful to know exactly what your build process is: manual, cpan, etc.

See also: any links in http://perldoc.perl.org/perl.html with descriptions matching /Unicode/; http://www.unicode.org/.

Hi Ken, thank you very much for your suggestions. I updated my post with the perlcommands you suggested. I just noticed something interesting on the linux-machine wenn running perl -d t/Encode.t :

DB<8> x $uni
0  '\x{03B1}'

DB<9> x is "\N{alpha}",substr($uni,0,1),"alpha does not map to symbol 
+'a'";
Unknown charname 'alpha' at (eval 23)[/usr/share/perl/5.18/perl5db.pl:
+732] line 2, within string

DB<10> x is "\N{greek:alpha}",substr($uni,0,1),"alpha does not map to 
+symbol 'a'";
ok 6 - alpha does not map to symbol 'a'
0  1
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So apparently, \N{alpha} is also wrong on the linux machine, but somehow the testcase does pass as "ok" anyways. Strange.

Unfortunately, changing alpha to greek:alpha didn't help on the AIX machine. AIX doesn't know about greek:alpha either.

I guess for now, that the Unicode-Table of linux and AIX differ. I am trying to find a way to display all availiable aliases of a unicode point. Something like this:


$unicode_module->get_char_aliases('U+03B1');

GREEK SMALL LETTER ALPHA
ALPHA
alpha
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Anyways, I will keep searching. Thanks for all your help so far.

Firstly, it seems I gave you something of a bum steer regarding &Unicode::UCD::charprops_all. I've been using it for a while and forgot that it was a fairly recent function (in terms of Perl versions). It was added in v5.22.0, along with some other functions, so won't be available on any of the Perl versions you're using. Sorry about that. See perl5220delta: Updated Modules and Pragmata.

[Just a quick note on markup. While it's generally preferable to use '<code>' tags for code and data, which you've been doing, this doesn't work too well with Unicode characters (outside the ASCII range). In these cases, '<pre>' tags work better: for instance, you'll see 'α' instead of '&#945;'. For inline text, such as in paragraphs, '<tt>' tags serve the same purpose.]

As I have neither Ubuntu nor AIX, I can't effectively reproduce your results. However, I looked into this a bit further and have a few other suggestions.

As you successfully printed the characters from the codepoints:

$ perl -C -E 'say "\x{3b1} - \x{df} - \x{a3}"'
α - ß - £

[I didn't need it, but you may need to add -Mutf8 to get rid of the "Wide character" message you're seeing.]

See what names you get for those characters:

$ perl -Mcharnames=:full -E 'say charnames::viacode($_) for (0x3b1, 0x
+df, 0xa3)'
GREEK SMALL LETTER ALPHA
LATIN SMALL LETTER SHARP S
POUND SIGN
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In terms of what you're referring to as "aliases", I suspect there's a very large number of these. Have a look at charnames; in particular, read what it says about :full, :loose and :short. There's a link to the algorithm for :loose matching, but it's horribly broken: it should be "http://www.unicode.org/reports/tr44/#Matching_Names". How :short is determined, is explained on the charnames page.

:full is fairly straighforward:

$ perl -C -E 'say "\N{GREEK SMALL LETTER ALPHA}"'
α

Based on that #Matching_Names algorithm, I then tried:

$ perl -C -E 'say "\N{greek small letter alpha}"'
Unknown charname 'greek small letter alpha' at -e line 1, within strin
+g
Execution of -e aborted due to compilation errors.
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However, when I specified -Mcharnames=:loose, it worked:

$ perl -Mcharnames=:loose -C -E 'say "\N{greek small letter alpha}"'
α

Bearing in mind the :loose algorithm, you can see there's a huge number of possibilities. Here's a few examples:

$ perl -Mcharnames=:loose -C -E 'say "\N{GREEK_SMALL_LETTER_ALPHA}"'
α
$ perl -Mcharnames=:loose -C -E 'say "\N{GREEK-SMALL-LETTER-ALPHA}"'
α
$ perl -Mcharnames=:loose -C -E 'say "\N{GREEK-SMALL_LETTER-ALPHA}"'
α
$ perl -Mcharnames=:loose -C -E 'say "\N{greek_small_letter_alpha}"'
α
$ perl -Mcharnames=:loose -C -E 'say "\N{greek-small_letter-alpha}"'
α
$ perl -Mcharnames=:loose -C -E 'say "\N{greek small-letter alpha}"'
α
$ perl -Mcharnames=:loose -C -E 'say "\N{GrEeK SmAlL-LeTtEr aLpHa}"'
α

Now, as shown in my earlier post, I was able to use the :short forms directly:

$ perl -C -E 'say "\N{greek:alpha}"'
α
$ perl -Mcharnames=greek -C -E 'say "\N{alpha}"'
α

They didn't work for you, but maybe these might:

$ perl -Mcharnames=:short -C -E 'say "\N{greek:alpha}"'
α
$ perl -Mcharnames=:short,greek -C -E 'say "\N{alpha}"'
α

I also had a brief look at the source code for charnames.pm and _charnames.pm; although, I didn't delve into them too deeply. There's a lot of (non-POD) comments that may be of interest. Perhaps have a look at those for the versions you're using.

— Ken

Further inspection of the problem leads me to the conclusion that this may not be related to encode. I fired up my Debugger and performed some tests. Notice how the Character \N{greek:alpha} was found on Linux, but not on AIX:
AIX 7.2:

  DB<1> use charnames qw(greek)

  DB<2> print "\N{alpha}"
Use of uninitialized value $txt in pattern match (m//) at /usr/opt/per
+l5/lib/5.20.1/_charnames.pm line 459.
 [...]
Unknown charname 'alpha' at (eval 9)[/usr/opt/perl5/lib/5.20.1/perl5db
+.pl:732] line 2, within string

  DB<3> print "\N{U+03B1}"
Wide character in print at (eval 10)[/usr/opt/perl5/lib/5.20.1/perl5db
+.pl:732] line 2.
 [...]
&#945;

  DB<4> print "\N{greek:alpha}"  
Use of uninitialized value $txt in pattern match (m//) at /usr/opt/per
+l5/lib/5.20.1/_charnames.pm line 459.
 [...]
Unknown charname 'greek:alpha' at (eval 11)[/usr/opt/perl5/lib/5.20.1/
+perl5db.pl:732] line 2, within string
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Ubuntu 14.04

 DB<1> use charnames qw(greek)

 DB<2> print "\N{alpha}"
 Unknown charname 'alpha' at (eval 8)[/usr/share/perl/5.18/perl5db.pl:
+732] line 2, within string

 DB<3> print "\N{U+03B1}"
 Wide character in print at (eval 9)[/usr/share/perl/5.18/perl5db.pl:7
+32] line 2.
 &#945;
  
 DB<4> print "\N{greek:alpha}"
 Wide character in print at (eval 10)[/usr/share/perl/5.18/perl5db.pl:
+732] line 2.
 &#945;
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Guess there is something messed up with the AIX character-table?