ใช้ function(); ใน str_replace ไม่ได้หรอครับ ช่วยผมหน่อยนะครับ

<?

include "config.php"; 
include "functions.php";

$template = "test1";

$categories = "<? categories(); ?>";
$recentblogs = "<? recentblogs(); ?>";
$tags = "<? include 'tags.php'; ?>";

$sidebar = file_get_contents("templates/$template/sidebar.html");
$sidebar = str_replace("{categories}", $categories ,$sidebar);
$sidebar = str_replace("{recentblogs}", $recentblogs ,$sidebar);
$sidebar = str_replace("{tags}", $tags ,$sidebar);

echo $sidebar;

?>

<?

//categories
function categories()
{
$categories=mysql_query("SELECT * FROM categories");

while ($category=mysql_fetch_array($categories))
	{
	echo "<li><a href=\"?site=category&amp;cat=$category[name]\">$category[name]</a></li>";
	}
}


//function to Recent Blogs
function recentblogs()
{
$num_recent = "5";
$recentblogs=mysql_query("SELECT * FROM news order by id desc LIMIT 0 , $num_recent");
while ($recent=mysql_fetch_array($recentblogs))
	{
$recent[title] = strip_tags($recent[title]);
echo "<li><a href='?site=news&amp;id=$recent[id]' title='$recent[title]'>$recent[title]</a></li>";
	}
}


?>

<?php
$values = '';
$result = mysql_query("SELECT tags FROM news");
while($row = mysql_fetch_array($result))
    $values .= $row['tags']." ";

$values = explode(' ', $values);
$values=(array_count_values($values));

array_multisort($values, SORT_DESC);
$values=array_slice($values, 0,10);
//SHUFFLE
   $randomized_keys = array_rand($values, count($values));
   foreach($randomized_keys as $current_key) {
   $values2[$current_key] = $values[$current_key]; 
   }

//ZA IZRACUN
foreach ($values2 as $name=>$value)
{
$kolk+=$value;
$ss+=1;
}
//ZA IZRACUN

//ZA IZPIS
foreach ($values2 as $name=>$value)
{
$size=$tagsize*$value/$kolk;
echo "<a href='$urlweb/?site=search&amp;keyword=$name'><strong>$name</strong></a> ";
}
//ZA IZPIS
?>