Although it’s easy to use WP Chili out of the box, WordPress does have some limitations, like the following:

• you need to change to the Code editor before adding a snippet to your post
• you need to make your snippet postable yourself, escaping all HTML entities
• even if snippets are very short, they are intermingled with their explanations and it’s tricky to concentrate on writing the best post with so many distractions in between

Using WP Chili & Enzymes

Now I’ll show you a better approach by using together WP Chili 1.0 and Enzymes 2.2.
All you need to be up and running is the classical roundtrip: download, unzip, upload, and activate.

How to highlight code snippets

You can start by writing a simple enzyme for automating things, like the following hilite custom field:

return 
'<pre><code class="' . $this->substrate . '">'
. htmlspecialchars( $this->pathway ) 
. '</code></pre>';

hilite can be used with the following patterns:

1. {[ =snippet= | .hilite( =language= ) ]}
2. {[ .snippet | .hilite( =language= ) ]}

The first pattern comes in handy when you want to highlight some very short and naive snippet
{[ =echo htmlentities( $name );= | .hilite( =php= ) ]} renders

echo htmlentities( $name );

So far, so good, but if the snippet has a character that WP texturizes, then hilite seems to fail. In fact
{[ =$welcome \= "Hello ".$name;= | .hilite( =php= ) ]} renders

$welcome = "Hello ".$name;

The above issue is not a hilite’s bug but it could be fixed by adding new code to it, or with new enzymes along the pathway, like the following requote custom field:

$from = array( '‘', '’', '“', '”' );
$to = array( "'", "'", '"', '"' );
return str_replace( $from, $to, $this->pathway );

which makes that
{[ =$welcome \= "Hello ".$name;= | .requote() | .hilite( =php= ) ]} renders

$welcome = "Hello ".$name;

The best option is to add another custom field for hosting your snippet and use the second pattern: in fact hilite’s snippet has been rendered by {[ .hilite | .hilite( =php= ) ]} and requote’s one by {[ .requote | .hilite( =php= ) ]}.

How to highlight code files

Sometimes you have a file that you want to show in its entirety, and having to copy it into a custom field is annoying or maybe not an option, if the file is alive, for example.

In such cases you can use an enzyme like the following file custom field:

return file_get_contents( $this->substrate );

It’s use is again very simple and very similar to the above patterns:
{[ .file( =blog/wp-content/plugins/hello.php= ) | .hilite( =php= ) ]} renders

<?php
/**
 * @package Hello_Dolly
 * @author Matt Mullenweg
 * @version 1.5.1
 */
/*
Plugin Name: Hello Dolly
Plugin URI: http://wordpress.org/#
Description: This is not just a plugin, it symbolizes the hope and enthusiasm of an entire generation summed up in two words sung most famously by Louis Armstrong: Hello, Dolly. When activated you will randomly see a lyric from <cite>Hello, Dolly</cite> in the upper right of your admin screen on every page.
Author: Matt Mullenweg
Version: 1.5.1
Author URI: http://ma.tt/
*/

function hello_dolly_get_lyric() {
	/** These are the lyrics to Hello Dolly */
	$lyrics = "Hello, Dolly
Well, hello, Dolly
It's so nice to have you back where you belong
You're lookin' swell, Dolly
I can tell, Dolly
You're still glowin', you're still crowin'
You're still goin' strong
We feel the room swayin'
While the band's playin'
One of your old favourite songs from way back when
So, take her wrap, fellas
Find her an empty lap, fellas
Dolly'll never go away again
Hello, Dolly
Well, hello, Dolly
It's so nice to have you back where you belong
You're lookin' swell, Dolly
I can tell, Dolly
You're still glowin', you're still crowin'
You're still goin' strong
We feel the room swayin'
While the band's playin'
One of your old favourite songs from way back when
Golly, gee, fellas
Find her a vacant knee, fellas
Dolly'll never go away
Dolly'll never go away
Dolly'll never go away again";

	// Here we split it into lines
	$lyrics = explode("\n", $lyrics);

	// And then randomly choose a line
	return wptexturize( $lyrics[ mt_rand(0, count($lyrics) - 1) ] );
}

// This just echoes the chosen line, we'll position it later
function hello_dolly() {
	$chosen = hello_dolly_get_lyric();
	echo "<p id='dolly'>$chosen</p>";
}

// Now we set that function up to execute when the admin_footer action is called
add_action('admin_footer', 'hello_dolly');

// We need some CSS to position the paragraph
function dolly_css() {
	// This makes sure that the posinioning is also good for right-to-left languages
	$x = ( 'rtl' == get_bloginfo( 'text_direction' ) ) ? 'left' : 'right';

	echo "
	<style type='text/css'>
	#dolly {
		position: absolute;
		top: 4.5em;
		margin: 0;
		padding: 0;
		$x: 215px;
		font-size: 11px;
	}
	</style>
	";
}

add_action('admin_head', 'dolly_css');

?>

One Response to “How to highlight code in WordPress”

1. Dennis "Best Songs" James says:

   2008-08-17 at 00:40:27

   Did the new version of WP fix this? Seems to be a rough way to work around the WP limitation with WP Chili.