charset: indicate continued columns without overlap
[sheet.git] / charset.plp
index 6577f4c4521f7b3b7a7cb337e5975f60dbb5c234..5955c390a6da4327d490972a7bc3ea585659c873 100644 (file)
@@ -2,7 +2,7 @@
 
 Html({
        title => 'charset cheat sheet',
-       version => 'v1.0',
+       version => '1.0',
        description => [
                "Reference sheet with all glyphs in common character encoding tables,",
                "and an overview of Unicode ranges and UTF-8 bytes.",
@@ -15,129 +15,472 @@ Html({
        data => [qw'charset-unicode.inc.pl charset-utf8.inc.pl'],
 });
 
+my @tablist = split m{/+}, $Request || 'default';
+
+use List::Util qw( first pairmap pairfirst pairs );
+
 :>
-<h1>Character encoding</h1>
+<h1>Character encodings</h1>
 
+<p>
 <:
+if ($tablist[0] eq 'default') {
+       say "Overview of Unicode allocation and common latin code pages.";
+       say "Compare alternate charsets:";
+}
+else {
+       say "Charset comparison:";
+}
+
+sub optionlink {
+       my ($title, $href, $selected) = @_;
+       return sprintf(
+               $selected ? '<strong>%s</strong>' : '<a href="%2$s">%s</a>',
+               EscapeHTML($title), $href
+       );
+}
+
+print join " •\n", (
+       map {
+               join " ·\n", pairmap {
+                       optionlink($b || ucfirst $a, '/charset'.($a && "/$a?compare"), $a eq $Request);
+               } @{$_}
+       }
+       [
+               iso      => 'ISO',
+               win      => 'Windows',
+               dos      => 'DOS',
+               mac      => 'Apple',
+               ebcdic   => 'EBCDIC',
+               $tablist[0] eq 'default' ? () : ('' => 'common'),
+       ],
+       [
+               westeur  => 'West',
+               centeur  => 'Central',
+               norteur  => 'North European',
+               turkish  => 0,
+               greek    => 0,
+               cyrillic => 0,
+               hebrew   => 0,
+       ],
+);
+:>.
+</p>
+
+<:
+use POSIX qw( ceil );
 use Shiar_Sheet::FormatChar;
 my $glyphs = Shiar_Sheet::FormatChar->new;
-my @nibble = (0..9, 'A'..'F');
-my $nibsize = 1;
-
-use Encode qw(decode resolve_alias);
-# generate character table(s)
-# (~16x faster than decoding in loop;
-#  substr strings is twice as fast as splitting to an array)
-my %ALIAS = (
-#      default => [qw(unicode utf-8 iso-8859-1 cp437 -cp1252- --iso-8859-15- -koi8-f)],
-       default => [qw(unicode- utf-8 iso-8859-1 -cp1252- --iso-8859-15- cp437 -cp850)],
-       0 => [qw(cp437 cp863)],
-       1 => [qw(iso-8859-1 cp1252 MacRoman cp850)],
-       2 => [qw(iso-8859-2 cp1250 cp852 MacCentralEurRoman MacCroatian MacRumanian)],
-       5 => [qw(koi8-f iso-8859-5 cp1251 MacCyrillic cp855 cp866)],
-       7 => [qw(iso-8859-7 cp1253 MacGreek cp737 cp869)],
-       8 => [qw(iso-8859-8 cp1255 MacHebrew cp862)],
-);
-my @request = map {
-       if (my $input = $_) {
-               my %row = (offset => 0);
-               my $endpoint = 255;
-               if ($input =~ s/^--//) {
-                       $row{offset} = $endpoint > 160 ? 160 : 48;
-               }
-               elsif ($input =~ s/^-//) {
-                       $row{offset} = $endpoint > 128 ? 128 : 32;
-               }
-               if ($input =~ s/-$//) {
-                       $endpoint = $row{offset} ? $row{offset} < 160 ? 159 : 191 : 127;
-               }
-
-               if ($input =~ /^U([0-9a-f]+)(?:-([0-9a-f]+))?/) {
-                       my $start = hex($1) << ($2 ? 4 : 8);
-                       my $end = $2 ? hex($2) << 4 : $start + 240;
-                       $row{table} = join '', map { chr } $start .. $end+15;
-                       utf8::upgrade($row{table});  # prevent latin1 output
-                       $row{set} = sprintf 'Unicode block U+%02Xxx', $start >> 8;
-               }
-               elsif ($input eq 'U') {
-                       $row{table} = ' ' x 512;
-                       $row{set} = 'Unicode planes';
-                       $row{cell} = do 'charset-ucplanes.inc.pl';
-                       @nibble = (map { $_.0, $_.8 } 0 .. 7);
-                       $nibsize = 8;
-               }
-               elsif ($row{set} = resolve_alias($input)) {
-                       if ($row{set} eq 'Internal') {
-                               $row{table} = ' ' x ($endpoint < 255 ? 640 : 8192);
-                               $row{set} = 'Unicode BMP';
-                               $row{cell} = do 'charset-unicode.inc.pl';
-                       }
-                       elsif ($row{set} eq 'utf-8-strict') {
-                               $row{table} = undef;
-                               $row{set} = 'UTF-8';
-                               $row{cell} = do 'charset-utf8.inc.pl';
+my @request;
+
+sub tabinput {
+       # generate character table(s)
+       my $input = shift or return;
+
+       state $ALIAS = {
+               default    => [qw( u+0-639 utf-8+realsize iso-8859-1 iso-8859-15 cp1252 cp437 cp850 )],
+               unicode    => [qw( uu+cols=32+realsize u+0-4095 u+4096-6319 u+6320-8191 )],
+               us         => [qw( cp437 cp863 gsm0338 AdobeStandardEncoding )],
+               ebcdic     => [qw( cp37 cp500 cp1047 posix-bc cp1026 cp875 )],
+               iso        => [map {"iso-8859-$_"} 1 .. 11, 13 .. 16],
+               dos        => [qw( cp437 cp865 cp861 cp860 cp863 cp850 cp857 cp852 cp775
+                                  cp737 cp869 cp866 cp855 cp862 cp864 )],
+               aix        => [qw( cp1006 )],
+               win        => [qw( cp1252 cp1250 cp1254 cp1257 cp1258 cp1253 cp1251 cp1255 cp1256 cp874 )],
+               mac        => [qw( MacRoman MacRomanian MacRumanian MacCroatian MacCentralEurRoman MacTurkish MacIcelandic MacSami
+                                  MacGreek MacCyrillic MacHebrew MacArabic MacFarsi MacThai )],
+
+               # languages
+               westeur    => [qw( iso-8859-1 iso-8859-15 cp1252 iso-8859-14 cp850 hp-roman8 nextstep MacRoman )],
+               centeur    => [qw( iso-8859-2 iso-8859-16 cp1250 cp852 MacRomanian MacCroatian MacCentralEurRoman )], # MacRumanian only for DB
+               turkish    => [qw( iso-8859-9 iso-8859-3 cp1254 cp857 MacTurkish )],
+               norteur    => [qw( baltic nordic )],
+               baltic     => [qw( iso-8859-4 iso-8859-13 cp1257 cp775 )],
+               nordic     => [qw( iso-8859-10 cp865 cp861 MacIcelandic MacSami )],
+               cyrillic   => [qw( koi8-r koi8-u koi8-f iso-8859-5 cp1251 MacCyrillic cp866 cp855
+                                  U4 U2DE-2DF UA64-A69 U50-52 )], # MacUkrainian is broken
+               arabic     => [qw( iso-8859-6 cp1256 MacArabic cp864 cp1006 MacFarsi
+                                  U6 U8A-8F+0-31+64 U75-77 )],
+               greek      => [qw( iso-8859-7 cp1253 MacGreek cp737 cp869  U37-3F U1F )],
+               hebrew     => [qw( iso-8859-8 cp1255 MacHebrew cp862  U59-5F )],
+               thai       => [qw( iso-8859-11 cp874 MacThai )],
+               vietnamese => [qw( viscii cp1258 MacVietnamese )],
+               symbol     => [qw( symbol dingbats MacDingbats AdobeZdingbat AdobeSymbol )],
+
+               # iso-code shorthand
+               1 => 'westeur',
+               2 => 'centeur',
+               3 => 'turkish',
+               4 => 'baltic',
+               5 => 'cyrillic',
+               6 => 'arabic',
+               7 => 'greek',
+               8 => 'hebrew',
+               9 => 'turkish',
+               10 => 'nordic',
+               11 => 'thai',
+       };
+       if (my $follow = $ALIAS->{$input}) {
+               tabinput($_) for ref $follow ? @{$follow} : $follow;
+               return;
+       }
+
+       state $visible = {};  # all present tables
+       my %row = (offset => 0, cols => 16);
+       my $params = $input =~ s/[+](.*)\z// ? $1 : undef;
+
+       if (not defined $params) {
+               state $INHERIT = {
+                       'cp437'       => ['cp850' => 0, 'ascii' => '0-31+128'], # ascii range overridden later
+                       'gsm0338'     => ['ascii' => '0-127'],
+
+                       'iso-8859-2'  => ['iso-8859-1' => '160'],
+                       'iso-8859-3'  => ['iso-8859-1' => '160'], #TODO: also apply to iso-8859-9
+                       'iso-8859-4'  => ['iso-8859-2' => '160'],
+                       'iso-8859-5'  => ['iso-8859-1' => '160'],
+                       'iso-8859-6'  => ['cp1256' => '128', 'iso-8859-1' => '160'],
+                       'iso-8859-7'  => ['iso-8859-1' => '160'],
+                       'iso-8859-8'  => ['iso-8859-1' => '160'],
+                       'iso-8859-9'  => ['iso-8859-1' => '208-223+240'],
+                       'iso-8859-10' => ['iso-8859-4' => '160'],
+                       'iso-8859-11' => ['iso-8859-1' => '160'],
+                       'iso-8859-13' => ['iso-8859-4' => '160'],
+                       'iso-8859-14' => ['iso-8859-1' => '160'],
+                       'iso-8859-15' => ['iso-8859-1' => '160-191'],
+                       'iso-8859-16' => ['iso-8859-2' => '160'],
+                       'hp-roman8'   => ['iso-8859-1' => '160'],
+
+                       'cp1252'      => ['iso-8859-1' => '128-159'],
+                       'cp1250'      => ['iso-8859-2' => '128-191', 'cp1252' => '128'],
+                       'cp1254'      => ['iso-8859-9' => '128-159', 'cp1252' => '128-159+208'],
+                       'cp874'       => ['iso-8859-11' => '128-159', 'cp1252' => '128'], # windows-874 actually cp1162
+                       'cp1257'      => ['iso-8859-13' => '128-159+255', 'cp1252' => '128'],
+                       'cp1251'      => ['cp1252' => '128'],
+                       'cp1253'      => ['cp1252' => '128'],
+                       'cp1255'      => ['iso-8859-8' => '128-223', 'cp1252' => '128'],
+                       'cp1256'      => ['cp1252' => '128'],
+                       'cp1258'      => ['cp1252' => '128-159+192'],
+
+                       'cp850'       => ['cp437' => '144'],
+                       'cp860'       => ['cp437' => '128-175'],
+                       'cp861'       => ['cp865' => '128-175'],
+                       'cp863'       => ['cp437' => '128-175'],
+                       'cp865'       => ['cp437' => '144-175'],
+                       'cp852'       => ['cp850' => '128', 'cp437' => '128'],
+                       'cp857'       => ['cp850' => '128-175+208-239', 'cp437' => '128'],
+                       'cp775'       => ['cp850' => '128'],  # partial cp437
+                       'cp866'       => ['cp437' => '128-175+224'],
+                       'cp855'       => ['cp437' => '128'],
+                       'cp1006'      => ['iso-8859-6' => '160', 'cp437' => '128'],
+                       'cp737'       => ['cp437' => '128-175+224'],
+                       'cp869'       => ['cp437' => '128'],
+                       'cp862'       => ['cp437' => '128-159'],
+                       'cp864'       => ['MacArabic' => '128', 'iso-8859-6' => '128', 'cp437' => '128'], #TODO: compare form variants
+
+                       'koi8-u'      => ['koi8-r' => '144-191'],
+                       'koi8-f'      => ['koi8-u' => '144-191'],
+
+                       'MacRomanian' => ['MacRoman' => '160-191+208-223'],
+                       'MacRumanian' => ['MacRomanian' => '160-191+208-223', 'MacRoman' => '160-191+208-223'],
+                       'MacCroatian' => ['MacRoman' => '160'],
+                       'MacCentralEurRoman' => ['MacRoman' => '128'],
+                       'MacIcelandic'=> ['MacRoman' => '160-175+208-239'],
+                       'MacTurkish'  => ['MacRoman' => '208-223'], # F5 is unassigned
+                       'MacSami'     => ['MacIcelandic' => '144-191+208-223+240', 'MacRoman' => '144'],
+                       'MacGreek'    => ['MacRoman' => '128'],
+                       'MacCyrillic' => ['MacRoman' => '128'],
+                       'MacHebrew'   => ['iso-8859-8' => '128', 'MacRoman' => '128-143+160'], # partial ascii
+                       'MacArabic'   => ['iso-8859-6' => '128', 'cp864' => '128', 'MacRoman' => '128'], #TODO: multiple parents
+                       'MacFarsi'    => ['MacArabic' => '176-191', 'MacRoman' => '128'],
+
+                       'cp37'        => ['posix-bc' => '0'],
+                       'posix-bc'    => ['cp1047' => '64'],
+                       'cp500'       => ['cp37' => '64-95+176-191'],
+                       'cp1047'      => ['cp37' => '16-47+80-95+160-191'],
+                       'cp1026'      => ['cp37' => '64'],
+                       'cp875'       => ['cp37' => '48'],
+
+               };
+
+               my @parents = @{ $INHERIT->{$input} || [] };
+
+               if (my ($parent, $part) = pairfirst { defined $visible->{$a} } @parents) {
+                       $row{parent} = $parent;
+                       $params = $part;
+                       $params = 128 unless $visible->{$parent}
+                               or ($input eq 'MacCroatian' and defined $visible->{MacRomanian});
+               }
+               elsif (defined $visible->{ascii}) {
+                       $row{parent} = $parents[0];
+                       $params = $parents[1] // 128;
+                       $params = 128 if $params >= 128;  # ascii offset at most
+               }
+               elsif (@parents) {
+                       $row{parent} = $parents[0];
+                       $params = $parents[1] if $parents[1] == 0;  # apply ascii end
+               }
+               $visible->{$_} //= 0 for $row{parent} || ();
+       }
+
+       for my $param (split /[+]+/, $params // '') {
+               if ($param eq 'realsize') {
+                       $row{realsize}++;
+               }
+               elsif ($param =~ m{ \A cols = (\d+) \z }x) {
+                       $row{cols} = $1;
+               }
+               elsif ($param =~ m{ \A (?<offset> \d+) (?: [-] (?<endpoint> \d+) )? \z }x) {
+                       if (defined $row{endpoint}) {
+                               # extend earlier range
+                               my $skip = int(($row{endpoint} || $row{offset}) / $row{cols});
+                               for ($skip + 1 .. ($+{offset} / $row{cols}) - 1) {
+                                       $row{skip}->{ $_ * $row{cols} - $row{offset} }++;
+                               }
                        }
                        else {
-                               $row{table} = decode($row{set}, pack 'C*', $row{offset} .. $endpoint);
+                               $row{offset} = $+{offset};
                        }
+                       $row{endpoint} = $+{endpoint} || 0;
                }
                else {
-                       print "<p>Encoding $input unknown</p>\n";
+                       Alert("Unknown option <q>$param</q> for charset $input");
                }
-               \%row;
+       }
+
+       if ($input =~ m{ \A u ([0-9a-f]+) (?:-([0-9a-f]+))? \z }ix) {
+               my $start = hex($1) << ($2 ? 4 : 8);
+               my $end = $2 ? (hex($2) << 4) + $row{cols} - 1 : $start + 255;
+               $row{table} = join '', map { chr } $start .. $end;
+               utf8::upgrade($row{table});  # prevent latin1 output
+               $row{endpoint} = $end - $start;
+               $row{set} = sprintf 'Unicode block U+%02Xxx', $start >> 8;
+               $row{offset} = $start % 256;
+       }
+       elsif (lc $input eq 'uu') {
+               $row{set} = 'Unicode planes';
+               $row{cell} = do 'charset-ucplanes.inc.pl'
+                       or Alert('Table data could not be read', $@ || $!);
+               $row{endpoint} = 1023 * $row{cell}->{colsize};
+       }
+       elsif (lc $input eq 'u') {
+               $row{cell} = do 'charset-unicode.inc.pl'
+                       or Alert('Table data could not be read', $@ || $!);
+
+               $row{endpoint} ||= 8191;
+               $row{endpoint}  *= $row{cell}->{colsize};
+               $row{startpoint} = $row{cell}->{colsize} * $row{offset};
+               $row{offset} = 0;
+               $row{set} = 'Unicode ' . (
+                       $row{startpoint} <  0x10000 && $row{endpoint} < 0x10000 ? 'BMP' :
+                       $row{startpoint} >= 0x10000 && $row{endpoint} < 0x20000 ? 'SMP' :
+                       'allocations'
+               );
+       }
+       elsif ($input =~ m/^utf-*8$/i) {
+               $row{set} = 'UTF-8';
+               $row{cell} = do 'charset-utf8.inc.pl'
+                       or Alert('Table data could not be read', $@ || $!);
+               $row{endpoint} = 255;
+       }
+       elsif ($row{set} = Encode::resolve_alias($input)) {
+               $row{endpoint} ||= 255;
+               if ($row{set} eq 'MacHebrew' or $row{set} eq 'MacThai') {
+                       # array of possibly multiple characters per code point
+                       $row{table} = [
+                               map { Encode::decode($row{set}, pack 'C*', $_) } $row{offset} .. $row{endpoint}
+                       ];
+               }
+               else {
+                       # ~16x faster than decoding in loop;
+                       # substr strings is twice as fast as splitting to an array
+                       $row{table} = Encode::decode($row{set}, pack 'C*', $row{offset} .. $row{endpoint});
+               }
+               $row{endpoint} -= $row{offset};
+
+               if ($row{set} eq 'cp437') {
+                       for my $phipos (237 - $row{offset}) {
+                               next if $phipos < 0 or $phipos > $row{endpoint};
+                               # replace phi glyph
+                               substr($row{table}, $phipos, 1) = pack 'U*', 0x3D5;
+                       }
+                       if ($row{offset} == 0) {
+                               # replace control characters by visible variants
+                               substr($row{table}, 0, 32) = pack 'U*', map {hex} qw(
+                                       2007 263A 263B 2665 2666 2663 2660 2022
+                                       25D8 25CB 25D9 2642 2640 266A 266B 263C
+                                       25BA 25C4 2195 203C 00B6 00A7 25AC 21A8
+                                       2191 2193 2192 2190 221F 2194 25B2 25BC
+                               );
+                       }
+               }
+
+               $visible->{ascii} =  # assume common base
+               $visible->{ $row{set} } = 1;
        }
        else {
-               ();
+               Alert("Encoding <q>$input</q> unknown");
+               return;
        }
-} map { defined $ALIAS{$_} ? @{ $ALIAS{$_} } : $_ }
-       $ENV{PATH_INFO} =~ /\w/ ? split(m{[/+\s]}, $ENV{PATH_INFO}) : 'default';
+       push @request, \%row;
+}
+tabinput($_) for @tablist;
+
 my $NOCHAR = chr 0xFFFD;
 
-for my $cp437 (grep {$request[$_]->{set} eq 'cp437'} 0 .. $#request) {
-       substr($request[$cp437]->{table}, 237, 1) = pack 'U*', 0x3D5; # phi sign
-       substr($request[$cp437]->{table}, 0, 32) = pack 'U*', map {hex} qw(
-               2007 263A 263B 2665 2666 2663 2660 2022 25D8 25CB 25D9 2642 2640 266A 266B 263C
-               25BA 25C4 2195 203C 00B6 00A7 25AC 21A8 2191 2193 2192 2190 221F 2194 25B2 25BC
-       );
+sub range_cell {
+       my ($info, $offset) = @_;
+       my $table = $info->{cell} or return;
+       my $def = $table->{$offset} or return;
+       my ($len, $class, $name, $title) = @{$def};
+
+       my $cols = $info->{cols};
+       my $colsize = $table->{colsize} || 1;
+       my $attr = '';
+       $len /= $colsize;
+       $name //= $len <= 2 ? 'res' : 'reserved';
+
+       if (my $part = $offset/$colsize % $cols) {
+               # continued row
+               my $rest = $cols - $part;  # remaining
+               $rest = $len if $len < $rest; #TODO: optimise
+               if ($len -= $rest) {
+                       # continued on new row
+                       my @next = ($len * $colsize, "$class joinu");
+                       my $separate = $cols - $len > $rest;  # columns not on next row
+                       if ($len > $rest) {
+                               # minority remains
+                               push @next, $name, $title;
+                               $title ||= $name;
+                               $name = $separate && '…';
+                       }
+                       else {
+                               # minority on next row
+                               push @next, $separate && '"', $title || $name;
+                       }
+                       $table->{$offset + $colsize*$rest} //= \@next;
+                       $class .= ' joind';
+               }
+               $len = $rest;
+       }
+       elsif (my $rows = int($len / $cols)) {
+               # multiple full rows
+               my $rowsize = $colsize * $cols;
+               if ($len -= $rows * $cols) {
+                       # partial row remains
+                       $table->{$offset + $rowsize * $rows} //= [$len*$colsize, "$class joinu", '', $title];
+                       $class .= ' joind';
+               }
+
+               unless ($info->{realsize}) {
+                       # coalesce multiple rows
+                       while ($rows > 3) {
+                               $info->{skip}->{$offset += $rowsize}++;
+                               $rows--;
+                       }
+                       if ($rows > 2) {
+                               $info->{skip}->{$offset += $rowsize} = 0;
+                       }
+               }
+
+               $attr .= sprintf ' rowspan=%d', $rows;
+               $len = $cols;
+       }
+
+       $attr .= sprintf ' colspan=%d', $len unless $len == 1;
+       $attr .= $1 if $class and $class =~ s/( \w+="[^"]*")//;
+       $attr .= sprintf ' class="%s"', $class if $class;
+       $attr .= sprintf ' title="%s"', EscapeHTML($title) if $title;
+       return "<td$attr>$name\n";
 }
 
 for my $row (@request) {
+       my $cols = $row->{cols};
+       my $colsize = $row->{cell} && $row->{cell}->{colsize} || 1;
+       my $coldigits = ceil(log($colsize * $cols) / log(16));  # uniform length of hexadecimal header
+       my $rowdiv = 16 ** $coldigits;  # row divide for column digits
+       $rowdiv = 1 if $rowdiv != $cols * $colsize;  # divide only if all columns are matched
+       my $offset = $row->{startpoint} || 0;
+
        printf '<div class="section"><table class="glyphs%s">', !$row->{cell} && ' charmap';
-       printf '<caption>%s</caption>', $row->{set};
-       print '<col>' x 17;
+       my $title = $row->{set};
+       $title .= " <aside>(over $_)</aside>"
+               for grep { $_ ne 'iso-8859-1' } $row->{parent} // ();
+       printf '<caption>%s</caption>', $title;
+       print '<col>' x ($cols + 1);
        for my $section (qw{thead}) {
-               print "<$section><tr><th>↱";
-               print '<th>', $_ for @nibble;
+               print "<$section><tr><th>", $rowdiv == 1 ? '+' : '↱';
+               printf '<th>%0*X', $coldigits, $_ * $colsize for 0 .. $cols - 1;
                print "\n";
        }
        print '<tbody>';
-       for my $msb (0 .. (length($row->{table}) || 256) - 1 >> 4) {
-               printf '<tr><th>%X', $msb + ($row->{offset} >> 4);
-               for my $lsb (0 .. $#nibble) {
-                       my $val = ( ($msb<<4) + $lsb ) * $nibsize;
+       while ($offset < $row->{endpoint}) {
+               if ($row->{skip}->{$offset}) {
+                       $offset += $cols * $colsize;
+                       next;
+               }
+
+               print '<tr><th>';
+               if (defined $row->{skip}->{$offset}) {
+                       print '⋮';
+               }
+               else {
+                       if (my $rowmod = $offset % $rowdiv) {
+                               # offset in column units
+                               printf '<small>+%X</small>', $rowmod;
+                       }
+                       else {
+                               # divided row offset
+                               printf '%X', ($offset + $row->{offset}) / $rowdiv;
+                       }
+               }
+               say '';
+
+               for (1 .. $cols) {
                        if ($row->{cell}) {
-                               print $row->{cell}->($val);
+                               print range_cell($row, $offset);
                                next;
                        }
 
-                       my $glyph = substr $row->{table}, $val, 1;
-                       if ($glyph eq $NOCHAR) {
-                               print '<td>';
-                               next;
+                       my $cp = $offset + $row->{offset};
+                       my $glyph = ref $row->{table} eq 'ARRAY' ? $row->{table}->[$offset] :
+                               substr $row->{table}, $offset, 1;
+                       my ($cell, $name, $class) = $glyph eq $NOCHAR ? () :
+                               $glyphs->glyph_html($glyph);
+
+                       if (exists $get{compare}) {
+                               state $visible = {};
+                               $class = (
+                                       $cp == ord $glyph ? 'l4' :
+                                       $row->{parent} && $glyph eq
+                                               Encode::decode($row->{parent}, pack 'C', $cp) ? 'l3' :
+                                       !$class ? undef :
+                                       $visible->{$glyph} ? 'l2' :
+                                       'l1'
+                               );
+                               $visible->{$glyph}++;
                        }
 
-                       print "\n".$glyphs->glyph_cell($glyph);
+                       say sprintf $class ? '<td title="%s" class="X %s">%s' : '<td title="%s">',
+                               $name, $class, $cell;
+               }
+               continue {
+                       $offset += $colsize;
                }
-               print "\n";
        }
-       print "</table></div>\n";
+       say '</table></div>';
 }
 
 :>
 <hr>
 
 <div class="legend">
-       <table class="glyphs"><tr>
+       <table class="glyphs"><tr><: if (exists $get{compare}) { :>
+       <td class="X l4">unicode
+       <td class="X l3">inherited
+       <td class="X l2">existing
+       <td class="X l1">original
+       <td class="">unassigned
+<: } else { :>
        <td class="X Cc">control
        <td class="X Zs"><span>whitespace</span>
        <td class="X Mn">diacritic<table class="glyphs"><tr>
@@ -174,6 +517,6 @@ for my $row (@request) {
        <td class="X Xd">deprecated
        <td class="">unassigned
        <td class="X Xi">invalid
-       </table>
+<: } :>        </table>
 </div>