Make qr/(?[ ])/ work in UTF-8 locales

Previously use of this under /l regex rules was a compile time error.
Now it works like \b{wb} and \b{sb}, which compile under locale rules
and always work like Unicode says they should.  A UTF-8 locale implies
Unicode rules, and the goal is for it to work seamlessly with the rest
of perl.  This construct was the only one I am aware of that didn't work
seamlessly (not counting OS interfaces) under UTF-8 LC_CTYPE locales.

For all three of these constructs, use with a non-UTF-8 runtime locale
raises a warning, and Unicode rules are used anyway.

UTF-8 locale collation still has problems, but this is low priority to
fix, as it's a lot of work, and if one really cares, one should be using
Unicode::Collate.

1 files changed, 6 insertions, 2 deletions

diff --git a/pod/perlrecharclass.pod b/pod/perlrecharclass.pod
index ce287710d2..f46de4c801 100644
--- a/pod/perlrecharclass.pod
+++ b/pod/perlrecharclass.pod
@@ -1106,8 +1106,12 @@ just three limitations:
 
 =item 1
 
-This construct cannot be used within the scope of
-C<use locale> (or the C<E<sol>l> regex modifier).
+When compiled within the scope of C<use locale> (or the C<E<sol>l> regex
+modifier), this construct assumes that the execution-time locale will be
+a UTF-8 one, and the generated pattern always uses Unicode rules.  What
+gets matched or not thus isn't dependent on the actual runtime locale, so
+tainting is not enabled.  But a C<locale> category warning is raised
+if the runtime locale turns out to not be UTF-8.
 
 =item 2