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Diffstat (limited to 'user_guide_src/source/libraries/parser.rst')
| -rw-r--r-- | user_guide_src/source/libraries/parser.rst | 242 |
1 files changed, 186 insertions, 56 deletions
diff --git a/user_guide_src/source/libraries/parser.rst b/user_guide_src/source/libraries/parser.rst index 5af504a03..d66684d9b 100644 --- a/user_guide_src/source/libraries/parser.rst +++ b/user_guide_src/source/libraries/parser.rst @@ -2,24 +2,26 @@ Template Parser Class ##################### -The Template Parser Class enables you to parse pseudo-variables -contained within your view files. It can parse simple variables or -variable tag pairs. If you've never used a template engine, -pseudo-variables look like this:: +The Template Parser Class can perform simple text substitution for +pseudo-variables contained within your view files. +It can parse simple variables or variable tag pairs. + +If you've never used a template engine, +pseudo-variable names are enclosed in braces, like this:: <html> - <head> - <title>{blog_title}</title> - </head> - <body> - - <h3>{blog_heading}</h3> - - {blog_entries} - <h5>{title}</h5> - <p>{body}</p> - {/blog_entries} - </body> + <head> + <title>{blog_title}</title> + </head> + <body> + <h3>{blog_heading}</h3> + + {blog_entries} + <h5>{title}</h5> + <p>{body}</p> + {/blog_entries} + + </body> </html> These variables are not actual PHP variables, but rather plain text @@ -28,8 +30,9 @@ representations that allow you to eliminate PHP from your templates .. note:: CodeIgniter does **not** require you to use this class since using pure PHP in your view pages lets them run a little faster. - However, some developers prefer to use a template engine if they work - with designers who they feel would find some confusion working with PHP. + However, some developers prefer to use a template engine if + they work with designers who they feel would find some + confusion working with PHP. .. important:: The Template Parser Class is **not** a full-blown template parsing solution. We've kept it very lean on purpose in order @@ -42,11 +45,15 @@ representations that allow you to eliminate PHP from your templates <div class="custom-index container"></div> +******************************* +Using the Template Parser Class +******************************* + Initializing the Class ====================== Like most other classes in CodeIgniter, the Parser class is initialized -in your controller using the $this->load->library function:: +in your controller using the ``$this->load->library()`` method:: $this->load->library('parser'); @@ -56,12 +63,13 @@ $this->parser Parsing templates ================= -You can use the ``parse()`` method to parse (or render) simple templates, like this:: +You can use the ``parse()`` method to parse (or render) simple templates, +like this:: $data = array( - 'blog_title' => 'My Blog Title', - 'blog_heading' => 'My Blog Heading' - ); + 'blog_title' => 'My Blog Title', + 'blog_heading' => 'My Blog Heading' + ); $this->parser->parse('blog_template', $data); @@ -74,7 +82,7 @@ template would contain two variables: {blog_title} and {blog_heading} There is no need to "echo" or do something with the data returned by $this->parser->parse(). It is automatically passed to the output class to be sent to the browser. However, if you do want the data returned -instead of sent to the output class you can pass TRUE (boolean) to the +instead of sent to the output class you can pass TRUE (boolean) as the third parameter:: $string = $this->parser->parse('blog_template', $data, TRUE); @@ -88,24 +96,24 @@ iteration containing new values? Consider the template example we showed at the top of the page:: <html> - <head> - <title>{blog_title}</title> - </head> - <body> - - <h3>{blog_heading}</h3> - - {blog_entries} - <h5>{title}</h5> - <p>{body}</p> - {/blog_entries} - </body> + <head> + <title>{blog_title}</title> + </head> + <body> + <h3>{blog_heading}</h3> + + {blog_entries} + <h5>{title}</h5> + <p>{body}</p> + {/blog_entries} + + </body> </html> In the above code you'll notice a pair of variables: {blog_entries} data... {/blog_entries}. In a case like this, the entire chunk of data between these pairs would be repeated multiple times, corresponding to -the number of rows in a result. +the number of rows in the "blog_entries" element of the parameters array. Parsing variable pairs is done using the identical code shown above to parse single variables, except, you will add a multi-dimensional array @@ -114,35 +122,156 @@ corresponding to your variable pair data. Consider this example:: $this->load->library('parser'); $data = array( - 'blog_title' => 'My Blog Title', - 'blog_heading' => 'My Blog Heading', - 'blog_entries' => array( - array('title' => 'Title 1', 'body' => 'Body 1'), - array('title' => 'Title 2', 'body' => 'Body 2'), - array('title' => 'Title 3', 'body' => 'Body 3'), - array('title' => 'Title 4', 'body' => 'Body 4'), - array('title' => 'Title 5', 'body' => 'Body 5') - ) - ); + 'blog_title' => 'My Blog Title', + 'blog_heading' => 'My Blog Heading', + 'blog_entries' => array( + array('title' => 'Title 1', 'body' => 'Body 1'), + array('title' => 'Title 2', 'body' => 'Body 2'), + array('title' => 'Title 3', 'body' => 'Body 3'), + array('title' => 'Title 4', 'body' => 'Body 4'), + array('title' => 'Title 5', 'body' => 'Body 5') + ) + ); $this->parser->parse('blog_template', $data); If your "pair" data is coming from a database result, which is already a -multi-dimensional array, you can simply use the database result_array() -function:: +multi-dimensional array, you can simply use the database ``result_array()`` +method:: $query = $this->db->query("SELECT * FROM blog"); $this->load->library('parser'); $data = array( - 'blog_title' => 'My Blog Title', - 'blog_heading' => 'My Blog Heading', - 'blog_entries' => $query->result_array() - ); + 'blog_title' => 'My Blog Title', + 'blog_heading' => 'My Blog Heading', + 'blog_entries' => $query->result_array() + ); $this->parser->parse('blog_template', $data); +Usage Notes +=========== + +If you include substitution parameters that are not referenced in your +template, they are ignored:: + + $template = 'Hello, {firstname} {lastname}'; + $data = array( + 'title' => 'Mr', + 'firstname' => 'John', + 'lastname' => 'Doe' + ); + $this->parser->parse_string($template, $data); + + // Result: Hello, John Doe + +If you do not include a substitution parameter that is referenced in your +template, the original pseudo-variable is shown in the result:: + + $template = 'Hello, {firstname} {initials} {lastname}'; + $data = array( + 'title' => 'Mr', + 'firstname' => 'John', + 'lastname' => 'Doe' + ); + $this->parser->parse_string($template, $data); + + // Result: Hello, John {initials} Doe + +If you provide a string substitution parameter when an array is expected, +i.e. for a variable pair, the substitution is done for the opening variable +pair tag, but the closing variable pair tag is not rendered properly:: + + $template = 'Hello, {firstname} {lastname} ({degrees}{degree} {/degrees})'; + $data = array( + 'degrees' => 'Mr', + 'firstname' => 'John', + 'lastname' => 'Doe', + 'titles' => array( + array('degree' => 'BSc'), + array('degree' => 'PhD') + ) + ); + $this->parser->parse_string($template, $data); + + // Result: Hello, John Doe (Mr{degree} {/degrees}) + +If you name one of your individual substitution parameters the same as one +used inside a variable pair, the results may not be as expected:: + + $template = 'Hello, {firstname} {lastname} ({degrees}{degree} {/degrees})'; + $data = array( + 'degree' => 'Mr', + 'firstname' => 'John', + 'lastname' => 'Doe', + 'degrees' => array( + array('degree' => 'BSc'), + array('degree' => 'PhD') + ) + ); + $this->parser->parse_string($template, $data); + + // Result: Hello, John Doe (Mr Mr ) + +View Fragments +============== + +You do not have to use variable pairs to get the effect of iteration in +your views. It is possible to use a view fragment for what would be inside +a variable pair, and to control the iteration in your controller instead +of in the view. + +An example with the iteration controlled in the view:: + + $template = '<ul>{menuitems} + <li><a href="{link}">{title}</a></li> + {/menuitems}</ul>'; + + $data = array( + 'menuitems' => array( + array('title' => 'First Link', 'link' => '/first'), + array('title' => 'Second Link', 'link' => '/second'), + ) + ); + $this->parser->parse_string($template, $data); + +Result:: + + <ul> + <li><a href="/first">First Link</a></li> + <li><a href="/second">Second Link</a></li> + </ul> + +An example with the iteration controlled in the controller, +using a view fragment:: + + $temp = ''; + $template1 = '<li><a href="{link}">{title}</a></li>'; + $data1 = array( + array('title' => 'First Link', 'link' => '/first'), + array('title' => 'Second Link', 'link' => '/second'), + ); + + foreach ($data1 as $menuitem) + { + $temp .= $this->parser->parse_string($template1, $menuitem, TRUE); + } + + $template = '<ul>{menuitems}</ul>'; + $data = array( + 'menuitems' => $temp + ); + $this->parser->parse_string($template, $data); + +Result:: + + <ul> + <li><a href="/first">First Link</a></li> + <li><a href="/second">Second Link</a></li> + </ul> + *************** Class Reference *************** @@ -167,8 +296,8 @@ Class Reference :returns: Parsed template string :rtype: string - This method works exactly like ``parse()``, only it accepts the template as a - string instead of loading a view file. + This method works exactly like ``parse()``, only it accepts + the template as a string instead of loading a view file. .. method:: set_delimiters([$l = '{'[, $r = '}']]) @@ -176,4 +305,5 @@ Class Reference :param string $r: Right delimiter :rtype: void - Sets the delimiters (opening and closing) for a value "tag" in a template.
\ No newline at end of file + Sets the delimiters (opening and closing) for a + pseudo-variable "tag" in a template.
\ No newline at end of file |