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perlunicodestringreverse

How can I reverse a string that contains combining characters in Perl?

I have the string "re\x{0301}sume\x{0301}" (which prints like this: résumé) and I want to reverse it to "e\x{0301}muse\x{0301}r" (émusér). I can't use Perl's reverse because it treats combining characters like "\x{0301}" as separate characters, so I wind up getting "\x{0301}emus\x{0301}er" ( ́emuśer). How can I reverse the string, but still respect the combining characters?

Solution

  • The best answer is to use Unicode::GCString, as Sinan points out

    I modified Chas's example a bit:

    • Set the encoding on STDOUT to avoid "wide character in print" warnings;
    • Use a positive lookahead assertion (and no separator retention mode) in split (doesn't work after 5.10, apparently, so I removed it)

    It's basically the same thing with a couple of tweaks.

    use strict;
use warnings;

binmode STDOUT, ":utf8";

my $original = "re\x{0301}sume\x{0301}";
my $wrong    = reverse $original;
my $right    = join '', reverse split /(\X)/, $original;

print <<HERE;
original: [$original]
   wrong: [$wrong]
   right: [$right]
HERE