Locale-aware Perl regular expressions (matching word boundaries)

Question

I'm currently somewhat stuck getting a regular expression in Perl (taken from an earlier question of mine) to match word characters from a non-ASCII locale (i.e., German umlauts).

I already tried various things such as setting the correct locale (using setlocale), converting data that I receive from MySQL to UTF8 (using decode_utf8), and so on... Unfortunately, to no avail. Google also did not help much.

Is there any chance to get the following regex locale-aware so that

$street = "Täststraße"; # I know that this is not orthographically correct
$street =~ s{
               \b (\w{0,3}) (\w*) \b
            }
            {
               $1 . ( '*' x length $2 )
            }gex;

ends up returning $street = "Täs*******" instead of "Tästs***ße"?

Answer 1

I would expect that the regex result in "Täs*******". And this is what I get when I "use utf8" in a utf-8 encoded file with your code above.

(If everything is latin-1, that changes the behavior of the regex engine. Hence the existence of utf8::upgrade. See Unicode::Semantics.)

Edit: I see you fixed your post and that we agree on the expected result. Basically, use Unicode::Semantics when you want Unicode semantics on your regexps.