From: karl williamson <public@khwilliamson.com>
Date: Wed, 3 Dec 2008 19:51:54 +0000 (-0700)
Subject: PATCH [perl #58430] Unicode::UCD::casefold() does not work as documented,
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=a452d459f5ff77fd7605dd9d2f58e9d44bc227cf;p=p5sagit%2Fp5-mst-13.2.git

PATCH [perl #58430] Unicode::UCD::casefold() does not work as documented,
Message-ID: <493745CA.6070300@khwilliamson.com>

And bump version to 0.27

p4raw-id: //depot/perl@35036
---

diff --git a/lib/Unicode/UCD.pm b/lib/Unicode/UCD.pm
index a760d3c..dc3fede 100644
--- a/lib/Unicode/UCD.pm
+++ b/lib/Unicode/UCD.pm
@@ -3,7 +3,7 @@ package Unicode::UCD;
 use strict;
 use warnings;
 
-our $VERSION = '0.26';
+our $VERSION = '0.27';
 
 use Storable qw(dclone);
 
@@ -61,9 +61,20 @@ Unicode::UCD - Unicode character database
 
 =head1 DESCRIPTION
 
-The Unicode::UCD module offers a simple interface to the Unicode
+The Unicode::UCD module offers a series of functions that
+provide a simple interface to the Unicode
 Character Database.
 
+=head2 code point argument
+
+Some of the functions are called with a I<code point argument>, which is either
+a decimal or a hexadecimal scalar designating a Unicode code point, or C<U+>
+followed by hexadecimals designating a Unicode code point.  In other words, if
+you want a code point to be interpreted as a hexadecimal number, you must
+prefix it with either C<0x> or C<U+>, because a string like e.g. C<123> will be
+interpreted as a decimal code point.  Also note that Unicode is B<not> limited
+to 16 bits (the number of Unicode code points is open-ended, in theory
+unlimited): you may have more than 4 hexdigits.
 =cut
 
 my $UNICODEFH;
@@ -92,46 +103,136 @@ sub openunicode {
     return $f;
 }
 
-=head2 charinfo
+=head2 B<charinfo()>
 
     use Unicode::UCD 'charinfo';
 
     my $charinfo = charinfo(0x41);
 
-charinfo() returns a reference to a hash that has the following fields
-as defined by the Unicode standard:
-
-    key
-
-    code             code point with at least four hexdigits
-    name             name of the character IN UPPER CASE
-    category         general category of the character
-    combining        classes used in the Canonical Ordering Algorithm
-    bidi             bidirectional type
-    decomposition    character decomposition mapping
-    decimal          if decimal digit this is the integer numeric value
-    digit            if digit this is the numeric value
-    numeric          if numeric is the integer or rational numeric value
-    mirrored         if mirrored in bidirectional text
-    unicode10        Unicode 1.0 name if existed and different
-    comment          ISO 10646 comment field
-    upper            uppercase equivalent mapping
-    lower            lowercase equivalent mapping
-    title            titlecase equivalent mapping
-
-    block            block the character belongs to (used in \p{In...})
-    script           script the character belongs to
-
-If no match is found, a reference to an empty hash is returned.
-
-The C<block> property is the same as returned by charinfo().  It is
-not defined in the Unicode Character Database proper (Chapter 4 of the
-Unicode 3.0 Standard, aka TUS3) but instead in an auxiliary database
-(Chapter 14 of TUS3).  Similarly for the C<script> property.
+This returns information about the input L</code point argument>
+as a reference to a hash of fields as defined by the Unicode
+standard.  If the L</code point argument> is not assigned in the standard
+(i.e., has the general category C<Cn> meaning C<Unassigned>)
+or is a non-character (meaning it is guaranteed to never be assigned in
+the standard),
+B<undef> is returned.
+
+Fields that aren't applicable to the particular code point argument exist in the
+returned hash, and are empty. 
+
+The keys in the hash with the meanings of their values are:
+
+=over
+
+=item B<code>
+
+the input L</code point argument> expressed in hexadecimal, with leading zeros
+added if necessary to make it contain at least four hexdigits
+
+=item B<name>
+
+name of I<code>, all IN UPPER CASE.
+Some control-type code points do not have names.
+This field will be empty for C<Surrogate> and C<Private Use> code points,
+and for the others without a name,
+it will contain a description enclosed in angle brackets, like
+C<E<lt>controlE<gt>>.
+
+
+=item B<category>
+
+The short name of the general category of I<code>.
+This will match one of the keys in the hash returned by L</general_categories()>.
+
+=item B<combining>
+
+the combining class number for I<code> used in the Canonical Ordering Algorithm.
+For Unicode 5.1, this is described in Section 3.11 C<Canonical Ordering Behavior>
+available at
+L<http://www.unicode.org/versions/Unicode5.1.0/>
+
+=item B<bidi>
+
+bidirectional type of I<code>.
+This will match one of the keys in the hash returned by L</bidi_types()>.
+
+=item B<decomposition>
+
+is empty if I<code> has no decomposition; or is one or more codes
+(separated by spaces) that taken in order represent a decomposition for
+I<code>.  Each has at least four hexdigits.
+The codes may be preceded by a word enclosed in angle brackets then a space,
+like C<E<lt>compatE<gt> >, giving the type of decomposition
+
+=item B<decimal>
+
+if I<code> is a decimal digit this is its integer numeric value
+
+=item B<digit>
+
+if I<code> represents a whole number, this is its integer numeric value
+
+=item B<numeric>
+
+if I<code> represents a whole or rational number, this is its numeric value.
+Rational values are expressed as a string like C<1/4>.
+
+=item B<mirrored>
+
+C<Y> or C<N> designating if I<code> is mirrored in bidirectional text
+
+=item B<unicode10>
+
+name of I<code> in the Unicode 1.0 standard if one
+existed for this code point and is different from the current name
+
+=item B<comment>
+
+ISO 10646 comment field.
+It appears in parentheses in the ISO 10646 names list,
+or contains an asterisk to indicate there is
+a note for this code point in Annex P of that standard.
+
+=item B<upper>
+
+is empty if there is no single code point uppercase mapping for I<code>;
+otherwise it is that mapping expressed as at least four hexdigits.
+(L</casespec()> should be used in addition to B<charinfo()>
+for case mappings when the calling program can cope with multiple code point
+mappings.)
+
+=item B<lower>
+
+is empty if there is no single code point lowercase mapping for I<code>;
+otherwise it is that mapping expressed as at least four hexdigits.
+(L</casespec()> should be used in addition to B<charinfo()>
+for case mappings when the calling program can cope with multiple code point
+mappings.)
+
+=item B<title>
+
+is empty if there is no single code point titlecase mapping for I<code>;
+otherwise it is that mapping expressed as at least four hexdigits.
+(L</casespec()> should be used in addition to B<charinfo()>
+for case mappings when the calling program can cope with multiple code point
+mappings.)
+
+=item B<block>
+
+block I<code> belongs to (used in \p{In...}).
+See L</Blocks versus Scripts>.
+
+
+=item B<script>
+
+script I<code> belongs to.
+See L</Blocks versus Scripts>.
+
+=back
 
 Note that you cannot do (de)composition and casing based solely on the
-above C<decomposition> and C<lower>, C<upper>, C<title>, properties,
-you will need also the compexcl(), casefold(), and casespec() functions.
+I<decomposition>, I<combining>, I<lower>, I<upper>, and I<title> fields;
+you will need also the L</compexcl()>, and L</casespec()> functions.
 
 =cut
 
@@ -305,29 +406,30 @@ sub charinrange {
     _search($range, 0, $#$range, $code);
 }
 
-=head2 charblock
+=head2 B<charblock()>
 
     use Unicode::UCD 'charblock';
 
     my $charblock = charblock(0x41);
     my $charblock = charblock(1234);
-    my $charblock = charblock("0x263a");
+    my $charblock = charblock(0x263a);
     my $charblock = charblock("U+263a");
 
     my $range     = charblock('Armenian');
 
-With a B<code point argument> charblock() returns the I<block> the character
-belongs to, e.g.  C<Basic Latin>.  Note that not all the character
-positions within all blocks are defined.
+With a L</code point argument> charblock() returns the I<block> the code point
+belongs to, e.g.  C<Basic Latin>.
+If the code point is unassigned, this returns the block it would belong to if
+it were assigned (which it may in future versions of the Unicode Standard).
 
 See also L</Blocks versus Scripts>.
 
 If supplied with an argument that can't be a code point, charblock() tries
-to do the opposite and interpret the argument as a character block. The
+to do the opposite and interpret the argument as a code point block. The
 return value is a I<range>: an anonymous list of lists that contain
 I<start-of-range>, I<end-of-range> code point pairs. You can test whether
-a code point is in a range using the L</charinrange> function. If the
-argument is not a known character block, C<undef> is returned.
+a code point is in a range using the L</charinrange()> function. If the
+argument is not a known code point block, B<undef> is returned.
 
 =cut
 
@@ -369,7 +471,7 @@ sub charblock {
     }
 }
 
-=head2 charscript
+=head2 B<charscript()>
 
     use Unicode::UCD 'charscript';
 
@@ -379,17 +481,18 @@ sub charblock {
 
     my $range      = charscript('Thai');
 
-With a B<code point argument> charscript() returns the I<script> the
-character belongs to, e.g.  C<Latin>, C<Greek>, C<Han>.
-
-See also L</Blocks versus Scripts>.
+With a L</code point argument> charscript() returns the I<script> the
+code point belongs to, e.g.  C<Latin>, C<Greek>, C<Han>.
+If the code point is unassigned, it returns B<undef>
 
 If supplied with an argument that can't be a code point, charscript() tries
-to do the opposite and interpret the argument as a character script. The
+to do the opposite and interpret the argument as a code point script. The
 return value is a I<range>: an anonymous list of lists that contain
 I<start-of-range>, I<end-of-range> code point pairs. You can test whether a
-code point is in a range using the L</charinrange> function. If the
-argument is not a known character script, C<undef> is returned.
+code point is in a range using the L</charinrange()> function. If the
+argument is not a known code point script, B<undef> is returned.
+
+See also L</Blocks versus Scripts>.
 
 =cut
 
@@ -434,14 +537,14 @@ sub charscript {
     }
 }
 
-=head2 charblocks
+=head2 B<charblocks()>
 
     use Unicode::UCD 'charblocks';
 
     my $charblocks = charblocks();
 
 charblocks() returns a reference to a hash with the known block names
-as the keys, and the code point ranges (see L</charblock>) as the values.
+as the keys, and the code point ranges (see L</charblock()>) as the values.
 
 See also L</Blocks versus Scripts>.
 
@@ -452,14 +555,14 @@ sub charblocks {
     return dclone \%BLOCKS;
 }
 
-=head2 charscripts
+=head2 B<charscripts()>
 
     use Unicode::UCD 'charscripts';
 
     my $charscripts = charscripts();
 
 charscripts() returns a reference to a hash with the known script
-names as the keys, and the code point ranges (see L</charscript>) as
+names as the keys, and the code point ranges (see L</charscript()>) as
 the values.
 
 See also L</Blocks versus Scripts>.
@@ -471,48 +574,12 @@ sub charscripts {
     return dclone \%SCRIPTS;
 }
 
-=head2 Blocks versus Scripts
-
-The difference between a block and a script is that scripts are closer
-to the linguistic notion of a set of characters required to present
-languages, while block is more of an artifact of the Unicode character
-numbering and separation into blocks of (mostly) 256 characters.
-
-For example the Latin B<script> is spread over several B<blocks>, such
-as C<Basic Latin>, C<Latin 1 Supplement>, C<Latin Extended-A>, and
-C<Latin Extended-B>.  On the other hand, the Latin script does not
-contain all the characters of the C<Basic Latin> block (also known as
-the ASCII): it includes only the letters, and not, for example, the digits
-or the punctuation.
-
-For blocks see http://www.unicode.org/Public/UNIDATA/Blocks.txt
-
-For scripts see UTR #24: http://www.unicode.org/unicode/reports/tr24/
-
-=head2 Matching Scripts and Blocks
-
-Scripts are matched with the regular-expression construct
-C<\p{...}> (e.g. C<\p{Tibetan}> matches characters of the Tibetan script),
-while C<\p{In...}> is used for blocks (e.g. C<\p{InTibetan}> matches
-any of the 256 code points in the Tibetan block).
-
-=head2 Code Point Arguments
-
-A I<code point argument> is either a decimal or a hexadecimal scalar
-designating a Unicode character, or C<U+> followed by hexadecimals
-designating a Unicode character.  In other words, if you want a code
-point to be interpreted as a hexadecimal number, you must prefix it
-with either C<0x> or C<U+>, because a string like e.g. C<123> will
-be interpreted as a decimal code point.  Also note that Unicode is
-B<not> limited to 16 bits (the number of Unicode characters is
-open-ended, in theory unlimited): you may have more than 4 hexdigits.
-
-=head2 charinrange
+=head2 B<charinrange()>
 
 In addition to using the C<\p{In...}> and C<\P{In...}> constructs, you
 can also test whether a code point is in the I<range> as returned by
-L</charblock> and L</charscript> or as the values of the hash returned
-by L</charblocks> and L</charscripts> by using charinrange():
+L</charblock()> and L</charscript()> or as the values of the hash returned
+by L</charblocks()> and L</charscripts()> by using charinrange():
 
     use Unicode::UCD qw(charscript charinrange);
 
@@ -567,18 +634,19 @@ sub general_categories {
     return dclone \%GENERAL_CATEGORIES;
 }
 
-=head2 general_categories
+=head2 B<general_categories()>
 
     use Unicode::UCD 'general_categories';
 
     my $categories = general_categories();
 
-The general_categories() returns a reference to a hash which has short
+This returns a reference to a hash which has short
 general category names (such as C<Lu>, C<Nd>, C<Zs>, C<S>) as keys and long
 names (such as C<UppercaseLetter>, C<DecimalNumber>, C<SpaceSeparator>,
 C<Symbol>) as values.  The hash is reversible in case you need to go
 from the long names to the short names.  The general category is the
-one returned from charinfo() under the C<category> key.
+one returned from
+L</charinfo()> under the C<category> key.
 
 =cut
 
@@ -605,40 +673,45 @@ my %BIDI_TYPES =
    'ON'  => 'Other Neutrals',
  ); 
 
-sub bidi_types {
-    return dclone \%BIDI_TYPES;
-}
-
-=head2 bidi_types
+=head2 B<bidi_types()>
 
     use Unicode::UCD 'bidi_types';
 
     my $categories = bidi_types();
 
-The bidi_types() returns a reference to a hash which has the short
+This returns a reference to a hash which has the short
 bidi (bidirectional) type names (such as C<L>, C<R>) as keys and long
 names (such as C<Left-to-Right>, C<Right-to-Left>) as values.  The
 hash is reversible in case you need to go from the long names to the
-short names.  The bidi type is the one returned from charinfo()
+short names.  The bidi type is the one returned from
+L</charinfo()>
 under the C<bidi> key.  For the exact meaning of the various bidi classes
 the Unicode TR9 is recommended reading:
-http://www.unicode.org/reports/tr9/tr9-17.html
+L<http://www.unicode.org/reports/tr9/>
 (as of Unicode 5.0.0)
 
 =cut
 
-=head2 compexcl
+sub bidi_types {
+    return dclone \%BIDI_TYPES;
+}
+
+=head2 B<compexcl()>
 
     use Unicode::UCD 'compexcl';
 
-    my $compexcl = compexcl("09dc");
+    my $compexcl = compexcl(0x09dc);
 
-The compexcl() returns the composition exclusion (that is, if the
-character should not be produced during a precomposition) of the 
-character specified by a B<code point argument>.
+This returns B<true> if the
+L</code point argument> should not be produced by composition normalization,
+B<AND> if that fact is not otherwise determinable from the Unicode data base.
+It currently does not return B<true> if the code point has a decomposition
+consisting of another single code point, nor if its decomposition starts
+with a code point whose combining class is non-zero.  Code points that meet
+either of these conditions should also not be produced by composition
+normalization.
 
-If there is a composition exclusion for the character, true is
-returned.  Otherwise, false is returned.
+It returns B<false> otherwise.
 
 =cut
 
@@ -670,46 +743,126 @@ sub compexcl {
     return exists $COMPEXCL{$code};
 }
 
-=head2 casefold
+=head2 B<casefold()>
 
     use Unicode::UCD 'casefold';
 
-    my $casefold = casefold("00DF");
+    my $casefold = casefold(0xDF);
+    if (defined $casefold) {
+        my @full_fold_hex = split / /, $casefold->{'full'};
+        my $full_fold_string =
+                    join "", map {chr(hex($_))} @full_fold_hex;
+        my @turkic_fold_hex =
+                        split / /, ($casefold->{'turkic'} ne "")
+                                        ? $casefold->{'turkic'}
+                                        : $casefold->{'full'};
+        my $turkic_fold_string =
+                        join "", map {chr(hex($_))} @turkic_fold_hex;
+    }
+    if (defined $casefold && $casefold->{'simple'} ne "") {
+        my $simple_fold_hex = $casefold->{'simple'};
+        my $simple_fold_string = chr(hex($simple_fold_hex));
+    }
 
-The casefold() returns the locale-independent case folding of the
-character specified by a B<code point argument>.
+This returns the (almost) locale-independent case folding of the
+character specified by the L</code point argument>.
 
-If there is a case folding for that character, a reference to a hash
+If there is no case folding for that code point, B<undef> is returned.
+
+If there is a case folding for that code point, a reference to a hash
 with the following fields is returned:
 
-    key
+=over
+
+=item B<code>
+
+the input L</code point argument> expressed in hexadecimal, with leading zeros
+added if necessary to make it contain at least four hexdigits
+
+=item B<full>
+
+one or more codes (separated by spaces) that taken in order give the
+code points for the case folding for I<code>.
+Each has at least four hexdigits.
+
+=item B<simple>
+
+is empty, or is exactly one code with at least four hexdigits which can be used
+as an alternative case folding when the calling program cannot cope with the
+fold being a sequence of multiple code points.  If I<full> is just one code
+point, then I<simple> equals I<full>.  If there is no single code point folding
+defined for I<code>, then I<simple> is the empty string.  Otherwise, it is an
+inferior, but still better-than-nothing alternative folding to I<full>.
+
+=item B<mapping>
+
+is the same as I<simple> if I<simple> is not empty, and it is the same as I<full>
+otherwise.  It can be considered to be the simplest possible folding for
+I<code>.  It is defined primarily for backwards compatibility.
+
+=item B<status>
 
-    code             code point with at least four hexdigits
-    status           "C", "F", "S", or "I"
-    mapping          one or more codes separated by spaces
+is C<C> (for C<common>) if the best possible fold is a single code point
+(I<simple> equals I<full> equals I<mapping>).  It is C<S> if there are distinct
+folds, I<simple> and I<full> (I<mapping> equals I<simple>).  And it is C<F> if
+there only a I<full> fold (I<mapping> equals I<full>; I<simple> is empty).  Note
+that this
+describes the contents of I<mapping>.  It is defined primarily for backwards
+compatibility.
 
-The meaning of the I<status> is as follows:
+On versions 3.1 and earlier of Unicode, I<status> can also be
+C<I> which is the same as C<C> but is a special case for dotted uppercase I and
+dotless lowercase i:
 
-   C                 common case folding, common mappings shared
-                     by both simple and full mappings
-   F                 full case folding, mappings that cause strings
-                     to grow in length. Multiple characters are separated
-                     by spaces
-   S                 simple case folding, mappings to single characters
-                     where different from F
-   I                 special case for dotted uppercase I and
-                     dotless lowercase i
-                     - If this mapping is included, the result is
-                       case-insensitive, but dotless and dotted I's
-                       are not distinguished
-                     - If this mapping is excluded, the result is not
-                       fully case-insensitive, but dotless and dotted
-                       I's are distinguished
+=over
 
-If there is no case folding for that character, C<undef> is returned.
+=item B<*>
+
+If you use this C<I> mapping, the result is case-insensitive,
+but dotless and dotted I's are not distinguished
+
+=item B<*>
+
+If you exclude this C<I> mapping, the result is not fully case-insensitive, but
+dotless and dotted I's are distinguished
+
+=back
+
+=item B<turkic>
+
+contains any special folding for Turkic languages.  For versions of Unicode
+starting with 3.2, this field is empty unless I<code> has a different folding
+in Turkic languages, in which case it is one or more codes (separated by
+spaces) that taken in order give the code points for the case folding for
+I<code> in those languages.
+Each code has at least four hexdigits.
+Note that this folding does not maintain canonical equivalence without
+additional processing.
+
+For versions of Unicode 3.1 and earlier, this field is empty unless there is a
+special folding for Turkic languages, in which case I<status> is C<I>, and
+I<mapping>, I<full>, I<simple>, and I<turkic> are all equal.  
+
+=back
+
+Programs that want complete generality and the best folding results should use
+the folding contained in the I<full> field.  But note that the fold for some
+code points will be a sequence of multiple code points.
+
+Programs that can't cope with the fold mapping being multiple code points can
+use the folding contained in the I<simple> field, with the loss of some
+generality.  In Unicode 5.1, about 7% of the defined foldings have no single
+code point folding.
+
+The I<mapping> and I<status> fields are provided for backwards compatibility for
+existing programs.  They contain the same values as in previous versions of
+this function.
+
+Locale is not completely independent.  The I<turkic> field contains results to
+use when the locale is a Turkic language.
 
 For more information about case mappings see
-http://www.unicode.org/unicode/reports/tr21/
+L<http://www.unicode.org/unicode/reports/tr21>
 
 =cut
 
@@ -720,11 +873,45 @@ sub _casefold {
 	if (openunicode(\$CASEFOLDFH, "CaseFolding.txt")) {
 	    local $_;
 	    while (<$CASEFOLDFH>) {
-		if (/^([0-9A-F]+); ([CFSI]); ([0-9A-F]+(?: [0-9A-F]+)*);/) {
+		if (/^([0-9A-F]+); ([CFIST]); ([0-9A-F]+(?: [0-9A-F]+)*);/) {
 		    my $code = hex($1);
-		    $CASEFOLD{$code} = { code    => $1,
-					 status  => $2,
-					 mapping => $3 };
+		    $CASEFOLD{$code}{'code'} = $1;
+		    $CASEFOLD{$code}{'turkic'} = "" unless
+					    defined $CASEFOLD{$code}{'turkic'};
+		    if ($2 eq 'C' || $2 eq 'I') {	# 'I' is only on 3.1 and
+							# earlier Unicodes
+							# Both entries there (I
+							# only checked 3.1) are
+							# the same as C, and
+							# there are no other
+							# entries for those
+							# codepoints, so treat
+							# as if C, but override
+							# the turkic one for
+							# 'I'.
+			$CASEFOLD{$code}{'status'} = $2;
+			$CASEFOLD{$code}{'full'} = $CASEFOLD{$code}{'simple'} =
+			$CASEFOLD{$code}{'mapping'} = $3;
+			$CASEFOLD{$code}{'turkic'} = $3 if $2 eq 'I';
+		    } elsif ($2 eq 'F') {
+			$CASEFOLD{$code}{'full'} = $3;
+			unless (defined $CASEFOLD{$code}{'simple'}) {
+				$CASEFOLD{$code}{'simple'} = "";
+				$CASEFOLD{$code}{'mapping'} = $3;
+				$CASEFOLD{$code}{'status'} = $2;
+			}
+		    } elsif ($2 eq 'S') {
+
+
+			# There can't be a simple without a full, and simple
+			# overrides all but full
+
+			$CASEFOLD{$code}{'simple'} = $3;
+			$CASEFOLD{$code}{'mapping'} = $3;
+			$CASEFOLD{$code}{'status'} = $2;
+		    } elsif ($2 eq 'T') {
+			$CASEFOLD{$code}{'turkic'} = $3;
+		    } # else can't happen because only [CIFST] are possible
 		}
 	    }
 	    close($CASEFOLDFH);
@@ -743,54 +930,85 @@ sub casefold {
     return $CASEFOLD{$code};
 }
 
-=head2 casespec
+=head2 B<casespec()>
 
     use Unicode::UCD 'casespec';
 
-    my $casespec = casespec("FB00");
+    my $casespec = casespec(0xFB00);
 
-The casespec() returns the potentially locale-dependent case mapping
-of the character specified by a B<code point argument>.  The mapping
-may change the length of the string (which the basic Unicode case
-mappings as returned by charinfo() never do).
+This returns the potentially locale-dependent case mappings of the L</code point
+argument>.  The mappings may be longer than a single code point (which the basic
+Unicode case mappings as returned by L</charinfo()> never are).
 
-If there is a case folding for that character, a reference to a hash
-with the following fields is returned:
+If there are no case mappings for the L</code point argument>, or if all three
+possible mappings (I<lower>, I<title> and I<upper>) result in single code
+points and are locale independent and uncondtional, B<undef> is returned.
+
+Otherwise, a reference to a hash giving the mappings (or a reference to a hash
+of such hashes, explained below) is returned.
+
+The keys in the bottom layer hash with the meanings of their values are:
+
+=over
+
+=item B<code>
+
+the input L</code point argument> expressed in hexadecimal, with leading zeros
+added if necessary to make it contain at least four hexdigits
+
+=item B<lower>
+
+one or more codes (separated by spaces) that taken in order give the
+code points for the lower case of I<code>.
+Each has at least four hexdigits.
+
+=item B<title>
 
-    key
+one or more codes (separated by spaces) that taken in order give the
+code points for the title case of I<code>.
+Each has at least four hexdigits.
 
-    code             code point with at least four hexdigits
-    lower            lowercase
-    title            titlecase
-    upper            uppercase
-    condition        condition list (may be undef)
+=item B<lower>
 
-The C<condition> is optional.  Where present, it consists of one or
-more I<locales> or I<contexts>, separated by spaces (other than as
-used to separate elements, spaces are to be ignored).  A condition
-list overrides the normal behavior if all of the listed conditions are
-true.  Case distinctions in the condition list are not significant.
+one or more codes (separated by spaces) that taken in order give the
+code points for the upper case of I<code>.
+Each has at least four hexdigits.
+
+=item B<condition>
+
+the conditions for the mappings to be valid.
+If B<undef>, the mappings are always valid.
+When defined, this field is a list of conditions,
+all of which must be true for the mappings to be valid.
+The list consists of one or more
+I<locales> (see below)
+and/or I<contexts> (explained in the next paragraph),
+separated by spaces.
+(Other than as used to separate elements, spaces are to be ignored.)
+Case distinctions in the condition list are not significant.
 Conditions preceded by "NON_" represent the negation of the condition.
 
-Note that when there are multiple case folding definitions for a
-single code point because of different locales, the value returned by
-casespec() is a hash reference which has the locales as the keys and
-hash references as described above as the values.
+A I<context> is one of those defined in the Unicode standard.
+For Unicode 5.1, they are defined in Section 3.13 C<Default Case Operations>
+available at
+L<http://www.unicode.org/versions/Unicode5.1.0/>
 
-A I<locale> is defined as a 2-letter ISO 3166 country code, possibly
+=back
+
+If the return value is to a hash of hashes, it is because there are multiple
+case mapping definitions for a single code point
+(because of different rules for different locales).
+Each sub-hash is of the form above, and the keys of the outer hash are
+the locales, which are
+defined as 2-letter ISO 3166 country codes, possibly
 followed by a "_" and a 2-letter ISO language code (possibly followed
-by a "_" and a variant code).  You can find the lists of those codes,
+by a "_" and a variant code).  You can find the lists of all possible locales,
 see L<Locale::Country> and L<Locale::Language>.
-
-A I<context> is one of the following choices:
-
-    FINAL            The letter is not followed by a letter of
-                     general category L (e.g. Ll, Lt, Lu, Lm, or Lo)
-    MODERN           The mapping is only used for modern text
-    AFTER_i          The last base character was "i" (U+0069)
+(In Unicode 5.1, the only locales returned by this function
+are C<lt>, C<tr>, and C<az>.)
 
 For more information about case mappings see
-http://www.unicode.org/unicode/reports/tr21/
+L<http://www.unicode.org/unicode/reports/tr21/>
 
 =cut
 
@@ -861,7 +1079,7 @@ sub casespec {
     return ref $CASESPEC{$code} ? dclone $CASESPEC{$code} : $CASESPEC{$code};
 }
 
-=head2 namedseq()
+=head2 B<namedseq()>
 
     use Unicode::UCD 'namedseq';
 
@@ -870,15 +1088,16 @@ sub casespec {
     my %namedseq = namedseq();
 
 If used with a single argument in a scalar context, returns the string
-consisting of the code points of the named sequence, or C<undef> if no
+consisting of the code points of the named sequence, or B<undef> if no
 named sequence by that name exists.  If used with a single argument in
-a list context, returns list of the code points.  If used with no
+a list context, it returns the list of the code points.  If used with no
 arguments in a list context, returns a hash with the names of the
 named sequences as the keys and the named sequences as strings as
-the values.  Otherwise, returns C<undef> or empty list depending
+the values.  Otherwise, it returns B<undef> or an empty list depending
 on the context.
 
-(New from Unicode 4.1.0)
+This function only operates on officially approved (not provisional) named
+sequences.
 
 =cut
 
@@ -920,10 +1139,9 @@ sub namedseq {
 
 =head2 Unicode::UCD::UnicodeVersion
 
-Unicode::UCD::UnicodeVersion() returns the version of the Unicode
-Character Database, in other words, the version of the Unicode
-standard the database implements.  The version is a string
-of numbers delimited by dots (C<'.'>).
+This returns the version of the Unicode Character Database, in other words, the
+version of the Unicode standard the database implements.  The version is a
+string of numbers delimited by dots (C<'.'>).
 
 =cut
 
@@ -940,6 +1158,32 @@ sub UnicodeVersion {
     return $UNICODEVERSION;
 }
 
+=head2 B<Blocks versus Scripts>
+
+The difference between a block and a script is that scripts are closer
+to the linguistic notion of a set of code points required to present
+languages, while block is more of an artifact of the Unicode code point
+numbering and separation into blocks of (mostly) 256 code points.
+
+For example the Latin B<script> is spread over several B<blocks>, such
+as C<Basic Latin>, C<Latin 1 Supplement>, C<Latin Extended-A>, and
+C<Latin Extended-B>.  On the other hand, the Latin script does not
+contain all the characters of the C<Basic Latin> block (also known as
+ASCII): it includes only the letters, and not, for example, the digits
+or the punctuation.
+
+For blocks see L<http://www.unicode.org/Public/UNIDATA/Blocks.txt>
+
+For scripts see UTR #24: L<http://www.unicode.org/unicode/reports/tr24/>
+
+=head2 B<Matching Scripts and Blocks>
+
+Scripts are matched with the regular-expression construct
+C<\p{...}> (e.g. C<\p{Tibetan}> matches characters of the Tibetan script),
+while C<\p{In...}> is used for blocks (e.g. C<\p{InTibetan}> matches
+any of the 256 code points in the Tibetan block).
+
+
 =head2 Implementation Note
 
 The first use of charinfo() opens a read-only filehandle to the Unicode
@@ -951,6 +1195,8 @@ if you are wondering where one of your filehandles went, that's where.
 
 Does not yet support EBCDIC platforms.
 
+L</compexcl()> should give a complete list of excluded code points.
+
 =head1 AUTHOR
 
 Jarkko Hietaniemi
diff --git a/lib/Unicode/UCD.t b/lib/Unicode/UCD.t
index 3362543..d64c932 100644
--- a/lib/Unicode/UCD.t
+++ b/lib/Unicode/UCD.t
@@ -1,6 +1,6 @@
 #!perl -w
 BEGIN {
-    if (ord("A") == 193) {
+    if (ord("A") != 65) {
 	print "1..0 # Skip: EBCDIC\n";
 	exit 0;
     }
@@ -18,7 +18,7 @@ use strict;
 use Unicode::UCD;
 use Test::More;
 
-BEGIN { plan tests => 194 };
+BEGIN { plan tests => 239 };
 
 use Unicode::UCD 'charinfo';
 
@@ -172,6 +172,26 @@ is($charinfo->{title},          '');
 is($charinfo->{block},          'Mathematical Alphanumeric Symbols');
 is($charinfo->{script},         'Common');
 
+$charinfo = charinfo(0x9FBA);	#Bug 58428
+
+is($charinfo->{code},           '9FBA', 'U+9FBA');
+is($charinfo->{name},           'CJK UNIFIED IDEOGRAPH-9FBA');
+is($charinfo->{category},       'Lo');
+is($charinfo->{combining},      '0');
+is($charinfo->{bidi},           'L');
+is($charinfo->{decomposition},  '');
+is($charinfo->{decimal},        '');
+is($charinfo->{digit},          '');
+is($charinfo->{numeric},        '');
+is($charinfo->{mirrored},       'N');
+is($charinfo->{unicode10},      '');
+is($charinfo->{comment},        '');
+is($charinfo->{upper},          '');
+is($charinfo->{lower},          '');
+is($charinfo->{title},          '');
+is($charinfo->{block},          'CJK Unified Ideographs');
+is($charinfo->{script},         'Han');
+
 use Unicode::UCD qw(charblock charscript);
 
 # 0x0590 is in the Hebrew block but unused.
@@ -254,6 +274,8 @@ ok(exists $bt->{L}, 'has L');
 is($bt->{L}, 'Left-to-Right', 'L is Left-to-Right');
 is($bt->{AL}, 'Right-to-Left Arabic', 'AL is Right-to-Left Arabic');
 
+# If this fails, then maybe one should look at the Unicode changes to see
+# what else might need to be updated.
 is(Unicode::UCD::UnicodeVersion, '5.1.0', 'UnicodeVersion');
 
 use Unicode::UCD qw(compexcl);
@@ -267,15 +289,70 @@ my $casefold;
 
 $casefold = casefold(0x41);
 
-ok($casefold->{code} eq '0041' &&
-   $casefold->{status} eq 'C'  &&
-   $casefold->{mapping} eq '0061', 'casefold 0x41');
+is($casefold->{code}, '0041', 'casefold 0x41 code');
+is($casefold->{status}, 'C', 'casefold 0x41 status');
+is($casefold->{mapping}, '0061', 'casefold 0x41 mapping');
+is($casefold->{full}, '0061', 'casefold 0x41 full');
+is($casefold->{simple}, '0061', 'casefold 0x41 simple');
+is($casefold->{turkic}, "", 'casefold 0x41 turkic');
 
 $casefold = casefold(0xdf);
 
-ok($casefold->{code} eq '00DF' &&
-   $casefold->{status} eq 'F'  &&
-   $casefold->{mapping} eq '0073 0073', 'casefold 0xDF');
+is($casefold->{code}, '00DF', 'casefold 0xDF code');
+is($casefold->{status}, 'F', 'casefold 0xDF status');
+is($casefold->{mapping}, '0073 0073', 'casefold 0xDF mapping');
+is($casefold->{full}, '0073 0073', 'casefold 0xDF full');
+is($casefold->{simple}, "", 'casefold 0xDF simple');
+is($casefold->{turkic}, "", 'casefold 0xDF turkic');
+
+# Do different tests depending on if version <= 3.1, or not.
+(my $version = Unicode::UCD::UnicodeVersion) =~ /^(\d+)\.(\d+)/;
+if (defined $1 && ($1 <= 2 || $1 == 3 && defined $2 && $2 <= 1)) {
+	$casefold = casefold(0x130);
+
+	is($casefold->{code}, '0130', 'casefold 0x130 code');
+	is($casefold->{status}, 'I' , 'casefold 0x130 status');
+	is($casefold->{mapping}, '0069', 'casefold 0x130 mapping');
+	is($casefold->{full}, '0069', 'casefold 0x130 full');
+	is($casefold->{simple}, "0069", 'casefold 0x130 simple');
+	is($casefold->{turkic}, "0069", 'casefold 0x130 turkic');
+
+	$casefold = casefold(0x131);
+
+	is($casefold->{code}, '0131', 'casefold 0x131 code');
+	is($casefold->{status}, 'I' , 'casefold 0x131 status');
+	is($casefold->{mapping}, '0069', 'casefold 0x131 mapping');
+	is($casefold->{full}, '0069', 'casefold 0x131 full');
+	is($casefold->{simple}, "0069", 'casefold 0x131 simple');
+	is($casefold->{turkic}, "0069", 'casefold 0x131 turkic');
+} else {
+	$casefold = casefold(0x49);
+
+	is($casefold->{code}, '0049', 'casefold 0x49 code');
+	is($casefold->{status}, 'C' , 'casefold 0x49 status');
+	is($casefold->{mapping}, '0069', 'casefold 0x49 mapping');
+	is($casefold->{full}, '0069', 'casefold 0x49 full');
+	is($casefold->{simple}, "0069", 'casefold 0x49 simple');
+	is($casefold->{turkic}, "0131", 'casefold 0x49 turkic');
+
+	$casefold = casefold(0x130);
+
+	is($casefold->{code}, '0130', 'casefold 0x130 code');
+	is($casefold->{status}, 'F' , 'casefold 0x130 status');
+	is($casefold->{mapping}, '0069 0307', 'casefold 0x130 mapping');
+	is($casefold->{full}, '0069 0307', 'casefold 0x130 full');
+	is($casefold->{simple}, "", 'casefold 0x130 simple');
+	is($casefold->{turkic}, "0069", 'casefold 0x130 turkic');
+}
+
+$casefold = casefold(0x1F88);
+
+is($casefold->{code}, '1F88', 'casefold 0x1F88 code');
+is($casefold->{status}, 'S' , 'casefold 0x1F88 status');
+is($casefold->{mapping}, '1F80', 'casefold 0x1F88 mapping');
+is($casefold->{full}, '1F00 03B9', 'casefold 0x1F88 full');
+is($casefold->{simple}, '1F80', 'casefold 0x1F88 simple');
+is($casefold->{turkic}, "", 'casefold 0x1F88 turkic');
 
 ok(!casefold(0x20));