After the basic introduction, we can now take a look at the syntax of the template tag system.
Before looking at specific tags, we should define what we should do as our tags. To write a tag, we use the <@ ... @> tag node. The left tag (<@) and the right tag (@>) are the default tags. If necessary, we can redefine these tags in it.
The template tag system now supports the following three types of tags: including directives, declarations and expressions. Let's take a look at these directives now.
Include instructions
Included directives allow us to separate content into many modules, such as header, footer or content. The included page can be HTML, or other tag template pages. According to an example, the following include directives can be used to include a header:
<@ include '' @>
An example containing instructions in the template context:
<html>
<head>
...
</head>
<body>
<center>
<table class='pageLayoutTable'>
<tr>
<td class='pageHeader'>
<@ include '' @>
</td>
</tr>
<!-- PAGE CONTENTS -->
...
<!-- PAGE FOOTER -->
...
</table>
...
</center>
</body>
</html>
Here, the header file content will be inserted on the main page when the page is sent to the user's browser. This header file contains an expression:
<!-- Page Header -->
<span>
<@ = @>
</span>
This expression will be compiled and will be output at runtime as:
<!-- Page Header -->
<span>
Flash Jacks' Sleek Tab Site
</span>
statement
Declaration allows us to declare a page-level variable in the template type, or even other pages. A declaration looks like the following code:
<@ salesAreaID = "Central District" @>
We are able to use declarations in template files:
<@ saleMonth = ('SALE_MONTH') @>
<@ saleTitle = ('SALE_TITLE') @>
<@ dealHeading = ('DEAL_HEADING') @>
<@ salesAreaID = "Central District" @>
<html>
<head>
<link rel='stylesheet' type='text/CSS' href="./style/"/>
<title>
...
</title>
</head>
<body>
...
</body>
</html>
In this example, we declare some page variables. The first 3 variables have been assigned a value in the ActionObject in the Action class we created: ('SALE_MONTH'). The fourth variable is assigned a string value: salesAreaID = "Central District".
The declared variables are now available in the page:
<!-- start_page_contents_include -->
...
<!-- Content section heading -->
<h4><@=dealHeading @> <@=saleMonth @></h4>
<center>
Clearance deals
<table class='productsTable'>
...
</table>
</center>
<center>
Todays specials
<table class='productsTable'>
...
</table>
</center>
...
<!-- end_page_contents_include -->
These page variables will be output as:
<!-- Content section heading -->
<h4>Jack's Super Deals for : May 2010</h4>
...
...
expression
The expression tag allows us to execute expressions in the template page. The result of the expression will be included in the template page. The following expression will be used to display a simple string (salesAreaID), and can also retrieve the properties of the framework configuration class:
<@ =salesAreaID @>
<@ = @>
In order to use these expressions, we have declared it before:
<@ salesAreaID = "Central District" @>
Or the property of the ViewResourcesConfig object (viewConfig) has been declared in the view-resources node:
<view-resources
appTitle = "Flash Jacks' Sleek Tab Site"
contactInfo = "@"
...
</view-resources>
When using objects in expressions, we can write an object-method declared in standard PHP symbols or dot-style symbols:
The PhpMVC_Tags Object-Method Notation
PHP Style sales = data->getSales
Dot Style sales =
With Method Params staff = ("STAFF")
Retrieve Data Array products = data->getValueBean("PRODUCTS_ARRAY")
In the next unit we will see how to use the template tag system to combine these to build a page.