Template::Declare::Tags - Build and install XML Tag subroutines for Template::Declare
package MyApp::Templates; use base 'Template::Declare'; use Template::Declare::Tags 'HTML'; template main => sub { link {} table { row { cell { "Hello, world!" } } } img { attr { src => 'cat.gif' } } img { src is 'dog.gif' } }; # Produces: # <link /> # <table> # <tr> # <td>Hello, world!</td> # </tr> # </table> # <img src="cat.gif" /> # <img src="dog.gif" /> package MyApp::Templates; use base 'Template::Declare'; use Template::Declare::Tags 'XUL', HTML => { namespace => 'html' }; template main => sub { groupbox { caption { attr { label => 'Colors' } } html::div { html::p { 'howdy!' } } html::br {} } }; # Produces: # <groupbox> # <caption label="Colors" /> # <html:div> # <html:p>howdy!</html:p> # </html:div> # <html:br></html:br> # </groupbox>
Template::Declare::Tags is used to generate and install subroutines for tags into the user's namespace.
Template::Declare::Tags
You can specify the tag sets used by providing a list of module list in the use statement:
use
use Template::Declare::Tags qw/ HTML XUL /;
By default, it uses the tag set provided by Template::Declare::TagSet::HTML. So
use Template::Declare::Tags;
is equivalent to
use Template::Declare::Tags 'HTML';
Currently Template::Declare bundles the following tag sets: Template::Declare::TagSet::HTML, Template::Declare::TagSet::XUL, Template::Declare::TagSet::RDF, and Template::Declare::TagSet::RDF::EM.
You can certainly specify your own tag set classes, as long as they subclass Template::Declare::TagSet and implement the corresponding methods (e.g. get_tag_list).
get_tag_list
If you implement a custom tag set module named Template::Declare::TagSet::Foo.
Template::Declare::TagSet::Foo
use Template::Declare::Tags 'Foo';
If you give the your tag set module a different name, say, MyTag::Foo, then you use the from option:
MyTag::Foo
from
use Template::Declare::Tags Foo => { from => 'MyTag::Foo' };
Then Template::Declare::Tags will no longer try to load Template::Declare::TagSet::Foo and MyTag::Foo will be loaded instead.
XML namespaces are emulated by Perl packages. For example, you can embed HTML tags within XUL using the html namespace:
html
package MyApp::Templates; use base 'Template::Declare'; use Template::Declare::Tags 'XUL', HTML => { namespace => 'html' }; template main => sub { groupbox { caption { attr { label => 'Colors' } } html::div { html::p { 'howdy!' } } html::br {} } };
This will give you
<groupbox> <caption label="Colors" /> <html:div> <html:p>howdy!</html:p> </html:div> <html:br></html:br> </groupbox>
Behind the scene, Template::Declare::Tags will generate a Perl package named html and install HTML tag subroutines into that package. On the other hand, XUL tag subroutines are installed into the current package, namely, MyApp::Templates in the previous example.
MyApp::Templates
There are cases when you want to specify a different Perl package for a perticular XML namespace name. For instance, the html Perl package has already been used for other purposes in your application and you don't want to install subs there and mess things up, then the package option can come to rescue:
package
package MyApp::Templates; use base 'Template::Declare'; use Template::Declare::Tags 'XUL', HTML => { namespace => 'htm', package => 'MyHtml' }; template main => sub { groupbox { caption { attr { label => 'Colors' } } MyHtml::div { MyHtml::p { 'howdy!' } } MyHtml::br {} } };
This code snippet will still generate something like the following:
<groupbox> <caption label="Colors" /> <htm:div> <htm:p>howdy!</htm:p> </htm:div> <htm:br></htm:br> </groupbox>
template declares a template in the current package. You can pass any url-legal characters in the template name. Template::Declare will encode the template as a perl subroutine and stash it to be called with show().
template
Template::Declare
show()
(Did you know that you can have characters like ":" and "/" in your Perl subroutine names? The easy way to get at them is with "can").
create_wrapper declares a wrapper subroutine that can be called like a tag sub, but can optionally take arguments to be passed to the wrapper sub. For example, if you wanted to wrap all of the output of a template in the usual HTML headers and footers, you can do something like this:
create_wrapper
package MyApp::Templates; use Template::Declare::Tags; use base 'Template::Declare'; BEGIN { create_wrapper wrap => sub { my $code = shift; my %params = @_; html { head { title { outs "Hello, $params{user}!"} }; body { $code->(); div { outs 'This is the end, my friend' }; }; } }; } template inner => sub { wrap { h1 { outs "Hello, Jesse, s'up?" }; } user => 'Jesse'; };
Note how the wrap wrapper function is available for calling after it has been declared in a BEGIN block. Also note how you can pass arguments to the function after the closing brace (you don't need a comma there!).
wrap
BEGIN
The output from the "inner" template will look something like this:
<html> <head> <title>Hello, Jesse!</title> </head> <body> <h1>Hello, Jesse, s'up?</h1> <div>This is the end, my friend</div> </body> </html>
private declares that a template isn't available to be called directly from client code.
private
With attr, you can specify attributes for HTML tags.
attr
Example:
p { attr { class => 'greeting text', id => 'welcome' }; 'This is a welcoming paragraph'; }
Tag attributes can also be specified by using is, as in
is
p { class is 'greeting text'; id is 'welcome'; 'This is a welcoming paragraph'; }
Emits XML declarators.
For example,
xml_decl { 'xml', version => '1.0' }; xml_decl { 'xml-stylesheet', href => "chrome://global/skin/", type => "text/css" };
will produce
<?xml version="1.0"?> <?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
outs HTML-encodes its arguments and appends them to Template::Declare's output buffer.
outs
outs_raw appends its arguments to Template::Declare's output buffer without doing any HTML escaping.
outs_raw
Help! I'm deprecated/
Sets up TAGNAME as a tag that can be used in user templates. TAGSET is an instance of a subclass for Template::Declare::TagSet.
with is an alternative way to specify attributes for a tag:
with
with ( id => 'greeting', class => 'foo' ), p { 'Hello, World wide web' };
The standard way to do this is:
p { attr { id => 'greeting', class => 'foo' } 'Hello, World wide web' };
# create a tag that has access to the arguments set with with. sub sample_smart_tag (&) { my $code = shift; smart_tag_wrapper { my %args = @_; # set using 'with' outs( 'keys: ' . join( ', ', sort keys %args) . "\n" ); $code->(); }; } # use it with ( foo => 'bar', baz => 'bundy' ), sample_smart_tag { outs( "Hello, World!\n" ); }; # output would be keys: baz, foo Hello, World!
The smart tag wrapper allows you to create code that has access to the arguments set using 'with', it passes them in to the wrapped code in @_. It also takes care of putting the output in the right place and tidying up after itself.
@_
show displays templates. args will be passed directly to the template.
show
args
show can either be called with a template name or a package/object and a template. (It's both functional and OO.)
If called from within a Template::Declare subclass, then private templates are accessible and visible. If called from something that isn't a Template::Declare, only public templates wil be visible.
From the outside world, users can either call Template::Declare-show()> or Template::Declare::tags::show() to render a publicly visible template.
Template::Declare-
Template::Declare::tags::show()
"private" templates may only be called from within the Template::Declare package.
Returns the absolute path of the current template
Import the templates from Package into the subpath 'path' of the current package, clobbering any of your own package's templates that you'd already defined.
Package
under is a helper function for the "import" semantic sugar.
under
@Template::Declare::Tags::EXPORT
Holds the names of the static subroutines exported by this class. tag subroutines generated from certain tag set, however, are not included here.
@Template::Declare::Tags::TAG_SUB_LIST
Contains the names of the tag subroutines generated from certain tag set.
Note that this array won't get cleared automatically before a another use Template::Decalre::Tags statement.
use Template::Decalre::Tags
@Template::Declare::Tags::TagSubs is aliased to this variable for backward-compatibility.
@Template::Declare::Tags::TagSubs
$Template::Declare::Tags::TAG_NEST_DEPTH
Controls the indentation of the XML tags in the final outputs. For example, you can temporarily disable a tag's indentation by the following lines of code:
body { pre { local $Template::Declare::Tags::TAG_NEST_DEPTH = 0; script { attr { src => 'foo.js' } } } }
It generates
<body> <pre> <script src="foo.js"></script> </pre> </body>
Note that now the script tag has no indentation and we've got what we want ;)
script
$Template::Declare::Tags::SKIP_XML_ESCAPING
Makes Template::Declare skip the XML escaping postprocessing entirely.
Template::Declare::TagSet::HTML, Template::Declare::TagSet::XUL, Template::Declare.
Jesse Vincent <jesse@bestpractical.com>, Agent Zhang <agentzh@yahoo.cn>
Copyright 2006-2007 Best Practical Solutions, LLC
To install Template::Declare, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Template::Declare
CPAN shell
perl -MCPAN -e shell install Template::Declare
For more information on module installation, please visit the detailed CPAN module installation guide.