structure.diff

diff --git a/lib/Mojo/DOM/HTML.pm b/lib/Mojo/DOM/HTML.pm
index 43c09fa..17e6be0 100644
--- a/lib/Mojo/DOM/HTML.pm
+++ b/lib/Mojo/DOM/HTML.pm
@@ -63,8 +63,24 @@ map { $END{$_} = ['p'] } (
   qw(h3 h4 h5 h6 header hr main menu nav ol p pre section table ul)
 );
 
-# HTML table elements with optional end tags
-my %TABLE = map { $_ => 1 } qw(colgroup tbody td tfoot th thead tr);
+# HTML elements with optional end tags and special scoping rules
+my @RULES = (
+  [
+    [qw(colgroup tbody tfoot thead)],
+    [qw(colgroup tbody td tfoot th thead tr)],
+    ['table']
+  ],
+  [[qw(dd dt)], [qw(dd dt)], ['dl']],
+  [['li'],      ['li'],      [qw(ul ol)]],
+  [[qw(td th)], [qw(td th)], ['table']],
+  [['tr'],      ['tr'],      ['table']]
+);
+my %CLOSE;
+for my $rule (@RULES) {
+  my $allowed = {map { $_ => 1 } @{$rule->[1]}};
+  my $scope   = {map { $_ => 1 } @{$rule->[2]}};
+  map { $CLOSE{$_} = [$allowed, $scope] } @{$rule->[0]};
+}
 
 # HTML elements without end tags
 my %EMPTY = map { $_ => 1 } (
@@ -165,17 +181,6 @@ sub parse {
 
 sub render { _render($_[0]->tree, $_[0]->xml) }
 
-sub _close {
-  my ($current, $allowed, $scope) = @_;
-
-  # Close allowed parent elements in scope
-  my $parent = $$current;
-  while ($parent->[0] ne 'root' && !$scope->{$parent->[1]}) {
-    _end($parent->[1], 0, $current) if $allowed->{$parent->[1]};
-    $parent = $parent->[3];
-  }
-}
-
 sub _end {
   my ($end, $xml, $current) = @_;
 
@@ -269,25 +274,15 @@ sub _start {
   if (!$xml && $$current->[0] ne 'root') {
     if (my $end = $END{$start}) { _end($_, 0, $current) for @$end }
 
-    # "dd" and "dt"
-    elsif ($start eq 'dd' || $start eq 'dt') {
-      _close($current, {dd => 1, dt => 1}, {dl => 1}) for qw(dd dt);
-    }
-
-    # "li"
-    elsif ($start eq 'li') { _close($current, {li => 1}, {ul => 1, ol => 1}) }
-
-    # "colgroup", "thead", "tbody" and "tfoot"
-    elsif ($start eq 'colgroup' || $start =~ /^t(?:head|body|foot)$/) {
-      _close($current, \%TABLE, {table => 1});
-    }
-
-    # "tr"
-    elsif ($start eq 'tr') { _close($current, {tr => 1}, {table => 1}) }
+    # Close allowed parent elements in scope
+    elsif (my $close = $CLOSE{$start}) {
+      my ($allowed, $scope) = @$close;
 
-    # "th" and "td"
-    elsif ($start eq 'th' || $start eq 'td') {
-      _close($current, {th => 1, td => 1}, {table => 1});
+      my $parent = $$current;
+      while ($parent->[0] ne 'root' && !$scope->{$parent->[1]}) {
+        _end($parent->[1], 0, $current) if $allowed->{$parent->[1]};
+        $parent = $parent->[3];
+      }
     }
   }