各位php高手帮我看看这段代码是什么意思
<br />
function apply_filters($tag, $value) {<br />
global $wp_filter, $merged_filters, $wp_current_filter;<br />
<br />
$args = array();<br />
<br />
if ( isset($wp_filter['all']) ) {<br />
$wp_current_filter[] = $tag;<br />
$args = func_get_args();<br />
_wp_call_all_hook($args);<br />
}<br />
<br />
if ( !isset($wp_filter[$tag]) ) {<br />
if ( isset($wp_filter['all']) )<br />
array_pop($wp_current_filter);<br />
return $value;<br />
}<br />
<br />
if ( !isset($wp_filter['all']) )<br />
$wp_current_filter[] = $tag;<br />
<br />
if ( !isset( $merged_filters[ $tag ] ) ) {<br />
ksort($wp_filter[$tag]);<br />
$merged_filters[ $tag ] = true;<br />
}<br />
<br />
reset( $wp_filter[ $tag ] );<br />
<br />
if ( empty($args) )<br />
$args = func_get_args();<br />
<br />
do {<br />
foreach( (array) current($wp_filter[$tag]) as $the_ )<br />
if ( !is_null($the_['function']) ){<br />
$args[1] = $value;<br />
$value = call_user_func_array($the_['function'], array_slice($args, 1, (int) $the_['accepted_args']));<br />
}<br />
<br />
} while ( next($wp_filter[$tag]) !== false );<br />
<br />
array_pop( $wp_current_filter );<br />
<br />
return $value;<br />
}<br />
<br />
function the_permalink() {<br />
echo apply_filters('the_permalink', get_permalink());<br />
}<br />
