<perl>
sub convert_ubb {
 $temp=$_[0];
 if ($temp=~ m/\[/) {
  $Neu="X";
  while ($Neu ne "") {
   $Neu="";
   $SStart = index($temp,"\[");
   $SEnde = index($temp,"\]");
   $STemp = substr($temp,$SStart+1,$SEnde-($SStart+1));
   if (index($STemp,"=") > 0) {
    $STag = uc(substr($STemp,0,index($STemp,"=")));
    $SParam = substr($STemp,index($STemp,"=")+1);
   } else {
    $STag=uc($STemp);
   }
   $ETemp=substr($temp,$SEnde+1);
   $EStart = index($ETemp,"\[/")+$SEnde+1;
   $EEnde = index($ETemp,"\]")+$SEnde+1;
   $ETag = uc(substr($temp,$EStart+1,$EEnde-($EStart+1)));
   $Inc = substr($temp,$SEnde+1,$EStart-($SEnde+1));
   $Alt = substr($temp,$SStart,$EEnde-($SStart-1));
   $Alt=~s/\[/\\\[/g;
   $Alt=~s/\]/\\]/g;
   if ($STag eq "URL") {
    if ($SParam eq "") {
     $SParam=$Inc;
     if (index($SParam,"://") < 0) {
      $SParam="http://".$SParam;
     }
    }
    $Neu="<a href=\"$SParam\">$Inc</a>";
   } elsif ($STag eq "EMAIL") {
    $Neu="<a href=\"mailto:$Inc\">$Inc</a>";
   } elsif ($STag eq "B") {
    $Neu="<b>$Inc</b>";
   } elsif ($STag eq "I") {
    $Neu="<i>$Inc</i>";
   } elsif ($STag eq "IMG") {
    $Neu="<img src=\"$Inc\">";
   } elsif ($STag eq "QUOTE") {
    $Neu="<blockquote>$Inc</blockquote>";
   } elsif ($STag eq "CODE") {
    $Neu="<pre>$Inc</pre>";
   }
   if ($Neu eq "") {
    last;
   }
   $temp=~s/$Alt/$Neu/;
  }
 }
 return $temp;
}
</perl>

<perl>
 out convert_ubb("[b]Test[/b]");
</perl>