util.php

<?php

function to_file($input){
    $input = str_replace(' ','_',$input);
    $input = str_replace('__','_',$input);
    $input = str_replace(',_',',',$input);
    $input = str_replace('_,',',',$input);
    $input = str_replace('-_','-',$input);
    $input = str_replace('_-','-',$input);
    $input = str_replace(',','__',$input);
    return $input;
}

function book_output($input){
    $input = str_replace('__',',',$input);
    $input = str_replace('_',' ',$input);
    $input = str_replace(',',', ',$input);
    $input = str_replace('-',' - ',$input);
    list($author,$title) = explode('-',$input,2);
    $author = trim($author);
    $title  = trim($title);

    if(!$title){
        $title = $author;
        $author = '';
    }

    return '<span class="title">'.htmlspecialchars($title).'</span>'.
           '<span class="author">'.htmlspecialchars($author).'</author>';
}