Document what's still to be done on the regular expression

Unicode support, based on the UTR#18.

p4raw-id: //depot/perl@12029

1 files changed, 65 insertions, 2 deletions

diff --git a/pod/perlunicode.pod b/pod/perlunicode.pod
index e6a14a7a92..ba73eb37c1 100644
--- a/pod/perlunicode.pod
+++ b/pod/perlunicode.pod
@@ -6,8 +6,8 @@ perlunicode - Unicode support in Perl
 
 =head2 Important Caveats
 
-WARNING: While the implementation of Unicode support in Perl is now fairly
-complete it is still evolving to some extent.
+WARNING: While the implementation of Unicode support in Perl is now
+fairly complete it is still evolving to some extent.
 
 In particular the way Unicode is handled on EBCDIC platforms is still
 rather experimental. On such a platform references to UTF-8 encoding
@@ -497,6 +497,69 @@ some attempt to apply 8-bit locale info to characters in the range
 characters above that range (when mapped into Unicode).  It will also
 tend to run slower.  Avoidance of locales is strongly encouraged.
 
+=head1 UNICODE REGULAR EXPRESSION SUPPORT LEVEL
+
+The following list of Unicode regular expression support describes
+feature by feature the Unicode support implemented in Perl as of Perl
+5.8.0.  The "Level N" and the section numbers refer to the Unicode
+Technical Report 18, "Unicode Regular Expression Guidelines".
+
+=over 4
+
+=item *
+
+Level 1 - Basic Unicode Support
+
+        2.1 Hex Notation                        - done          [1]
+                Named Notation                  - done          [2]
+        2.2 Categories                          - done          [3][4]
+        2.3 Subtraction                         - MISSING       [5][6]
+        2.4 Simple Word Boundaries              - done          [7]
+        2.5 Simple Loose Matches                - MISSING       [8]
+        2.6 End of Line                         - MISSING       [9][10]
+
+        [ 1] \x{...}
+        [ 2] \N{...}
+        [ 3] . \p{Is...} \P{Is...}
+        [ 4] now scripts (see UTR#24 Script Names) in  addition to blocks
+        [ 5] have negation
+        [ 6] can use look-ahead to emulate subtracion
+        [ 7] include Letters in word characters
+        [ 8] see UTR#21 Case Mappings
+        [ 9] see UTR#13 Unicode Newline Guidelines
+        [10] should do ^ and $ also on \x{2028} and \x{2029}
+
+=item *
+
+Level 2 - Extended Unicode Support
+
+        3.1 Surrogates                          - MISSING
+        3.2 Canonical Equivalents               - MISSING       [11][12]
+        3.3 Locale-Independent Graphemes        - MISSING       [13]
+        3.4 Locale-Independent Words            - MISSING       [14]
+        3.5 Locale-Independent Loose Matches    - MISSING       [15]
+
+        [11] see UTR#15 Unicode Normalization
+        [12] have Unicode::Normalize but not integrated to regexes
+        [13] have \X but at this level . should equal that
+        [14] need three classes, not just \w and \W
+        [15] see UTR#21 Case Mappings
+
+=item *
+
+Level 3 - Locale-Sensitive Support
+
+        4.1 Locale-Dependent Categories         - MISSING
+        4.2 Locale-Dependent Graphemes          - MISSING       [16][17]
+        4.3 Locale-Dependent Words              - MISSING
+        4.4 Locale-Dependent Loose Matches      - MISSING
+        4.5 Locale-Dependent Ranges             - MISSING
+
+        [16] see UTR#10 Unicode Collation Algorithms
+        [17] have Unicode::Collate but not integrated to regexes
+
+=back
+
 =head1 SEE ALSO
 
 L<bytes>, L<utf8>, L<perlretut>, L<perlvar/"${^WIDE_SYSTEM_CALLS}">