Case Mappings? http://www.unicode.org/unicode/reports/tr21/
-lc(), uc(), lcfirst(), and ucfirst() work only for some of the
-simplest cases, where the mapping goes from a single Unicode character
-to another single Unicode character. See lib/unicore/SpecCase.txt
-(and CaseFold.txt).
+Mostly implemented (all of 1:1, 1:N, N:1), only the "final sigma"
+and locale-specific rules of SpecCase are not implemented.
=item *
UTF-8 in package names and sub names? The first is problematic
because of the mapping to pathnames, ditto for the second one if
-one does autosplitting, for example.
+one does autosplitting, for example. Some of this works already
+in 5.8.0, but essentially it is unsupported. Constructs to consider,
+at the very least:
+
+ use utf8;
+ package UnicodePackage;
+ sub new { bless {}, shift };
+ sub UnicodeMethod1 { ... $_[0]->UnicodeMethod2(...) ... }
+ sub UnicodeMethod2 { ... } # in here caller(0) should contain Unicode
+ ...
+ package main;
+ my $x = UnicodePackage->new;
+ print ref $x, "\n"; # should be Unicode
+ $x->UnicodeMethod1(...);
+ my $y = UnicodeMethod3 UnicodePackage ...;
+
+In the above all I<UnicodeXxx> contain (identifier-worthy) characters
+beyond the code point 255, for example 256. Wherever package/class or
+subroutine names can be returned needs to be checked for Unicodeness.
=back