xml.diff

diff --git a/lib/Mojo/DOM/HTML.pm b/lib/Mojo/DOM/HTML.pm
index 026170e..0c3496f 100644
--- a/lib/Mojo/DOM/HTML.pm
+++ b/lib/Mojo/DOM/HTML.pm
@@ -227,8 +227,9 @@ sub _render {
 
   # Attributes
   for my $key (sort keys %{$tree->[2]}) {
-    $result .= " $key" and next unless defined(my $value = $tree->[2]{$key});
-    $result .= " $key" . '="' . xml_escape($value) . '"';
+    my $value = $tree->[2]{$key};
+    $result .= " $key" and next if !defined $value && !$xml;
+    $result .= " $key" . '="' . xml_escape($value // $key) . '"';
   }
 
   # No children
diff --git a/lib/Mojolicious/Plugin/TagHelpers.pm b/lib/Mojolicious/Plugin/TagHelpers.pm
index f76afa7..e805811 100644
--- a/lib/Mojolicious/Plugin/TagHelpers.pm
+++ b/lib/Mojolicious/Plugin/TagHelpers.pm
@@ -18,15 +18,15 @@ sub register {
       sub { _input(shift, shift, value => shift, @_, type => 'checkbox') });
   $app->helper(csrf_field => \&_csrf_field);
   $app->helper(file_field =>
-      sub { shift; _tag('input', name => shift, @_, type => 'file') });
+      sub { _tag(shift, 'input', name => shift, @_, type => 'file') });
 
   $app->helper(form_for     => \&_form_for);
   $app->helper(hidden_field => \&_hidden_field);
-  $app->helper(image => sub { _tag('img', src => shift->url_for(shift), @_) });
-  $app->helper(input_tag => sub { _input(@_) });
-  $app->helper(javascript => \&_javascript);
-  $app->helper(label_for  => \&_label_for);
-  $app->helper(link_to    => \&_link_to);
+  $app->helper(image        => \&_image);
+  $app->helper(input_tag    => sub { _input(@_) });
+  $app->helper(javascript   => \&_javascript);
+  $app->helper(label_for    => \&_label_for);
+  $app->helper(link_to      => \&_link_to);
 
   $app->helper(password_field => \&_password_field);
   $app->helper(radio_button =>
@@ -37,10 +37,11 @@ sub register {
   $app->helper(submit_button => \&_submit_button);
 
   # "t" is just a shortcut for the "tag" helper
-  $app->helper($_ => sub { shift; _tag(@_) }) for qw(t tag);
+  $app->helper($_ => \&_tag) for qw(t tag);
 
   $app->helper(tag_with_error => \&_tag_with_error);
   $app->helper(text_area      => \&_text_area);
+  $app->helper(xml => sub { local shift->stash->{'mojo.xml'} = 1; shift->() });
 }
 
 sub _csrf_field {
@@ -63,12 +64,16 @@ sub _form_for {
     @post = (method => 'POST') if $methods{POST} && !$methods{GET};
   }
 
-  return _tag('form', action => $c->url_for(@url), @post, @_);
+  return _tag($c, 'form', action => $c->url_for(@url), @post, @_);
 }
 
 sub _hidden_field {
+  _tag(shift, 'input', name => shift, value => shift, @_, type => 'hidden');
+}
+
+sub _image {
   my $c = shift;
-  return _tag('input', name => shift, value => shift, @_, type => 'hidden');
+  return _tag($c, 'img', src => $c->url_for(shift), @_);
 }
 
 sub _input {
@@ -99,7 +104,7 @@ sub _javascript {
   my $content
     = ref $_[-1] eq 'CODE' ? "//<![CDATA[\n" . pop->() . "\n//]]>" : '';
   my @src = @_ % 2 ? (src => $c->url_for(shift)) : ();
-  return _tag('script', @src, @_, sub {$content});
+  return _tag($c, 'script', @src, @_, sub {$content});
 }
 
 sub _label_for {
@@ -121,15 +126,15 @@ sub _link_to {
   # Captures
   push @url, shift if ref $_[0] eq 'HASH';
 
-  return _tag('a', href => $c->url_for(@url), @_);
+  return _tag($c, 'a', href => $c->url_for(@url), @_);
 }
 
 sub _option {
-  my ($values, $pair) = @_;
+  my ($c, $values, $pair) = @_;
   $pair = [$pair => $pair] unless ref $pair eq 'ARRAY';
   my %attrs = (value => $pair->[1]);
   $attrs{selected} = undef if exists $values->{$pair->[1]};
-  return _tag('option', %attrs, @$pair[2 .. $#$pair], $pair->[0]);
+  return _tag($c, 'option', %attrs, @$pair[2 .. $#$pair], $pair->[0]);
 }
 
 sub _password_field {
@@ -149,12 +154,12 @@ sub _select_field {
     # "optgroup" tag
     if (blessed $group && $group->isa('Mojo::Collection')) {
       my ($label, $values, %attrs) = @$group;
-      my $content = join '', map { _option(\%values, $_) } @$values;
-      $groups .= _tag('optgroup', label => $label, %attrs, sub {$content});
+      my $content = join '', map { _option($c, \%values, $_) } @$values;
+      $groups .= _tag($c, 'optgroup', label => $label, %attrs, sub {$content});
     }
 
     # "option" tag
-    else { $groups .= _option(\%values, $group) }
+    else { $groups .= _option($c, \%values, $group) }
   }
 
   return _validation($c, $name, 'select', name => $name, %attrs,
@@ -165,17 +170,16 @@ sub _stylesheet {
   my $c = shift;
   my $content
     = ref $_[-1] eq 'CODE' ? "/*<![CDATA[*/\n" . pop->() . "\n/*]]>*/" : '';
-  return _tag('style', @_, sub {$content}) unless @_ % 2;
-  return _tag('link', rel => 'stylesheet', href => $c->url_for(shift), @_);
+  return _tag($c, 'style', @_, sub {$content}) unless @_ % 2;
+  return _tag($c, 'link', rel => 'stylesheet', href => $c->url_for(shift), @_);
 }
 
 sub _submit_button {
-  my $c = shift;
-  return _tag('input', value => shift // 'Ok', @_, type => 'submit');
+  _tag(shift, 'input', value => shift // 'Ok', @_, type => 'submit');
 }
 
 sub _tag {
-  my $tree = ['tag', shift, undef, undef];
+  my ($c, $tree) = (shift, ['tag', shift, undef, undef]);
 
   # Content
   if (ref $_[-1] eq 'CODE') { push @$tree, ['raw', pop->()] }
@@ -191,14 +195,15 @@ sub _tag {
     delete $attrs->{data};
   }
 
-  return Mojo::ByteStream->new(Mojo::DOM::HTML::_render($tree));
+  return Mojo::ByteStream->new(
+    Mojo::DOM::HTML::_render($tree, $c->stash->{'mojo.xml'}));
 }
 
 sub _tag_with_error {
   my ($c, $tag) = (shift, shift);
   my ($content, %attrs) = (@_ % 2 ? pop : undef, @_);
   $attrs{class} .= $attrs{class} ? ' field-with-error' : 'field-with-error';
-  return _tag($tag, %attrs, defined $content ? $content : ());
+  return _tag($c, $tag, %attrs, defined $content ? $content : ());
 }
 
 sub _text_area {
@@ -213,7 +218,7 @@ sub _text_area {
 
 sub _validation {
   my ($c, $name) = (shift, shift);
-  return _tag(@_) unless $c->validation->has_error($name);
+  return _tag($c, @_) unless $c->validation->has_error($name);
   return $c->helpers->tag_with_error(@_);
 }
 
@@ -235,7 +240,7 @@ Mojolicious::Plugin::TagHelpers - Tag helpers plugin
 
 =head1 DESCRIPTION
 
-L<Mojolicious::Plugin::TagHelpers> is a collection of HTML tag helpers for
+L<Mojolicious::Plugin::TagHelpers> is a collection of HTML/XML tag helpers for
 L<Mojolicious>.
 
 Most form helpers can automatically pick up previous input values and will
@@ -642,7 +647,8 @@ Alias for L</"tag">.
   <%= tag div => (id => 'foo') => begin %>test & 123<% end %>
 
 HTML tag generator, the C<data> attribute may contain a hash reference with
-pairs to generate attributes from.
+pairs to generate attributes from. You can also use L</"xml"> to generate XML
+tags instead.
 
   <br>
   <div></div>
@@ -757,6 +763,18 @@ automatically get picked up and shown as default.
   <input name="vacation" type="week" value="2012-W17">
   <input id="foo" name="vacation" type="week" value="2012-W17">
 
+=head2 xml
+
+  %= xml begin
+    %= tag link => 'http://example.com'
+    %= image '/images/foo.png'
+  % end
+
+Switch to generating XML tags with L</"tag">.
+
+  <link>http://example.com</link>
+  <img src="/path/to/images/foo.png" />
+
 =head1 METHODS
 
 L<Mojolicious::Plugin::TagHelpers> inherits all methods from
diff --git a/t/mojo/dom.t b/t/mojo/dom.t
index 05afe01..18e4023 100644
--- a/t/mojo/dom.t
+++ b/t/mojo/dom.t
@@ -272,6 +272,8 @@ ok $dom->at('b')->contents->first->xml, 'XML mode active';
 ok $dom->at('b')->contents->first->replace('<br>')->contents->first->xml,
   'XML mode active';
 is "$dom", '<b><br /><image /></b>', 'right result';
+is $dom->at('b')->attr(hidden => undef),
+  '<b hidden="hidden"><br /><image /></b>', 'right result';
 
 # Treating nodes as elements
 $dom = Mojo::DOM->new('foo<b>bar</b>baz');
diff --git a/t/mojolicious/tag_helper_lite_app.t b/t/mojolicious/tag_helper_lite_app.t
index 68a6bfe..fdc452a 100644
--- a/t/mojolicious/tag_helper_lite_app.t
+++ b/t/mojolicious/tag_helper_lite_app.t
@@ -52,6 +52,8 @@ is app->select_field(country => $values),
 # Basic tags
 $t->options_ok('/tags')->status_is(200)->content_is(<<EOF);
 <foo></foo>
+  <foo />
+  <link>http://example.com</link>
 <foo bar="baz"></foo>
 <foo one="t&lt;wo" three="four">Hello</foo>
 <div data-my-test-id="1" data-name="test">some content</div>
@@ -473,6 +475,10 @@ done_testing();
 __DATA__
 @@ tags.html.ep
 <%= tag 'foo' %>
+<%= xml begin =%>
+  <%= tag 'foo' %>
+  <%= tag link => 'http://example.com' %>
+<% end =%>
 <%= tag 'foo', bar => 'baz' %>
 <%= tag 'foo', one => 't<wo', three => 'four' => begin %>Hello<% end %>
 <%= tag 'div', data => {my_test_ID => 1, naMe => 'test'} => 'some content' %>