zacscott/bbcode.php

## bbcode.php
<?php

/**
 * Renders BBCode to html, suitable to be embedded in a document.  Supports only
 * a limited set of BBCode tags (can be extended), which are:
 *
 * @param $bbcode The bbcode to be rendered.  Must not be `null` or empty
 * string.
 * @param $reps Optional additional replacements.  Allows you to add custom tags
 * etc.  Should be an associative array, mapping a regex (preg) to replacement.
 * For example: `array('{\[b\](.+?)\[/b\]}is' => "<b>$1</b>\n")` adds the
 * [b] tag.
 */
function bbcode($bbcode, $reps = array()) {
	assert($bbcode != null && $bbcode != '');

	// first encode any HTML special charaters
	$bbcode = htmlentities($bbcode);

	// ensure paragraph structure
	$bbcode = "<p>$bbcode</p>";

	// single lines to paragraph break
	$bbcode = preg_replace('/^\s*$/m', '</p><p>', $bbcode);

	// add built-in regex replacements to perform (i.e. core bbcode tags)
	$reps['{\[b\](.+?)\[/b\]}is'] =  "<b>$1</b>\n"; // [b] - bold
	$reps['{\[i\](.+?)\[/i\]}is'] =  "<i>$1</i>\n"; // [i] - italic
	$reps['{\[u\](.+?)\[/u\]}is'] =  "<u>$1</u>\n"; // [u] - underline
	$reps['{\[s\](.+?)\[/s\]}is'] =  "<s>$1</s>\n"; // [s] - strikethrough
	$reps['{\[color=(.+?)\](.*?)\[/color\]}is'] = "<span style='color:$1;'>$2</span>\n"; // [color]
	$reps['{\[quote\](.*?)\[/quote\]}is'] =  "</p>\n<blockquote><p>\n$1\n</p></blockquote>\n<p>\n"; // [quote]
	$reps['{\[code\](.*?)\[/code\]}is'] =  "<pre>$1</pre>\n"; // [code]
	$reps['{\[url\](.+?)\[/url\]}is'] =  "<a href='$1'>$1</a>\n"; // [url] - raw url
	$reps['{\[url=(.*?)\](.+?)\[/url\]}is'] =  "<a href='$1'>$2</a>\n"; // [url=] - with text
	$reps['{\[img\](.*?)\[/img\]}is'] =  "<img src='$1' alt=''/>\n"; // [img]
	$reps['{\[ul\](.*?)\[/ul\]}is'] = 	"</p>\n<ul>$1</ul>\n<p>\n"; // [ul] - unordered list
	$reps['{\[ol\](.*?)\[/ol\]}is'] =  "</p>\n<ol>$1</ol>\n<p>\n"; // [ol] - ordered list
	$reps['{\[\*\](.*?)\[/\*\]}is'] =  "<li>\n<p>\n$1\n</p>\n</li>\n"; // [*] - list item

	// perform replacements
	foreach ($reps as $regex => $replace)
		$bbcode = preg_replace($regex, $replace, $bbcode);

	return $bbcode;

}

?>

## bbcode_test.php
<?php

require_once dirname(__FILE__).'/code/bbcode.php';

$bbcode = isset($_POST['bbcode']) ?
	$_POST['bbcode']:
	'[quote]Write some [b]bbcode[/b] here![/quote]';

?>
<!DOCTYPE HTML>
<html lang="en-US">
<head>
	<meta charset="UTF-8">
	<title></title>
</head>
<body>
	<h1>BBCode Test</h1>
	<form action="bbcode.php" method="post">
		<label for="bbcode">BBCode:</label>
		<textarea name="bbcode" cols="30" rows="10"><?php echo $bbcode ?></textarea>
		<input type="submit" value="Preview"/>
	</form>
	<h2>Output</h2>
	<?php
	if (isset($bbcode))
		echo bbcode($bbcode);
	?>
</body>
</html>
	<?php

	/**
	* Renders BBCode to html, suitable to be embedded in a document. Supports only
	* a limited set of BBCode tags (can be extended), which are:
	*
	* @param $bbcode The bbcode to be rendered. Must not be `null` or empty
	* string.
	* @param $reps Optional additional replacements. Allows you to add custom tags
	* etc. Should be an associative array, mapping a regex (preg) to replacement.
	* For example: `array('{\[b\](.+?)\[/b\]}is' => "<b>$1</b>\n")` adds the
	* [b] tag.
	*/
	function bbcode($bbcode, $reps = array()) {
	assert($bbcode != null && $bbcode != '');

	// first encode any HTML special charaters
	$bbcode = htmlentities($bbcode);

	// ensure paragraph structure
	$bbcode = "<p>$bbcode</p>";

	// single lines to paragraph break
	$bbcode = preg_replace('/^\s*$/m', '</p><p>', $bbcode);

	// add built-in regex replacements to perform (i.e. core bbcode tags)
	$reps['{\[b\](.+?)\[/b\]}is'] = "<b>$1</b>\n"; // [b] - bold
	$reps['{\[i\](.+?)\[/i\]}is'] = "<i>$1</i>\n"; // [i] - italic
	$reps['{\[u\](.+?)\[/u\]}is'] = "<u>$1</u>\n"; // [u] - underline
	$reps['{\[s\](.+?)\[/s\]}is'] = "<s>$1</s>\n"; // [s] - strikethrough
	$reps['{\[color=(.+?)\](.*?)\[/color\]}is'] = "<span style='color:$1;'>$2</span>\n"; // [color]
	$reps['{\[quote\](.*?)\[/quote\]}is'] = "</p>\n<blockquote><p>\n$1\n</p></blockquote>\n<p>\n"; // [quote]
	$reps['{\[code\](.*?)\[/code\]}is'] = "<pre>$1</pre>\n"; // [code]
	$reps['{\[url\](.+?)\[/url\]}is'] = "<a href='$1'>$1</a>\n"; // [url] - raw url
	$reps['{\[url=(.*?)\](.+?)\[/url\]}is'] = "<a href='$1'>$2</a>\n"; // [url=] - with text
	$reps['{\[img\](.*?)\[/img\]}is'] = "<img src='$1' alt=''/>\n"; // [img]
	$reps['{\[ul\](.*?)\[/ul\]}is'] = "</p>\n<ul>$1</ul>\n<p>\n"; // [ul] - unordered list
	$reps['{\[ol\](.*?)\[/ol\]}is'] = "</p>\n<ol>$1</ol>\n<p>\n"; // [ol] - ordered list
	$reps['{\[\\](.?)\[/\\]}is'] = "<li>\n<p>\n$1\n</p>\n</li>\n"; // [] - list item

	// perform replacements
	foreach ($reps as $regex => $replace)
	$bbcode = preg_replace($regex, $replace, $bbcode);

	return $bbcode;

	}

	?>
	<?php

	require_once dirname(__FILE__).'/code/bbcode.php';

	$bbcode = isset($_POST['bbcode']) ?
	$_POST['bbcode']:
	'[quote]Write some [b]bbcode[/b] here![/quote]';

	?>
	<!DOCTYPE HTML>
	<html lang="en-US">
	<head>
	<meta charset="UTF-8">
	<title></title>
	</head>
	<body>
	<h1>BBCode Test</h1>
	<form action="bbcode.php" method="post">
	<label for="bbcode">BBCode:</label>
	<textarea name="bbcode" cols="30" rows="10"><?php echo $bbcode ?></textarea>
	<input type="submit" value="Preview"/>
	</form>
	<h2>Output</h2>
	<?php
	if (isset($bbcode))
	echo bbcode($bbcode);
	?>
	</body>
	</html>