> So you found sanitize_title (you're good enough at PHP)

Well, I didn't find it by checking the source but during a google research. Someone pointed to the sanitize_title function when it comes to permalink creation.

So I downloaded the WordPress source code and found it in formatting.php.

To be honest I also found the apply_filters function in wp-includes/plugin.php when trying to understand what "sanitize_title" does.

But apply_filters as well as sanitize_title gives me no clue what WordPress does to convert the title. I expected to find some php string manipulation but apply_filters is all greek to me.

function apply_filters($tag, $value) {
    global $wp_filter, $merged_filters, $wp_current_filter;

    $args = array();
    $wp_current_filter[] = $tag;

    // Do 'all' actions first
    if ( isset($wp_filter['all']) ) {
        $args = func_get_args();
        _wp_call_all_hook($args);
    }

    if ( !isset($wp_filter[$tag]) ) {
        array_pop($wp_current_filter);
        return $value;
    }

    // Sort
    if ( !isset( $merged_filters[ $tag ] ) ) {
        ksort($wp_filter[$tag]);
        $merged_filters[ $tag ] = true;
    }

    reset( $wp_filter[ $tag ] );

    if ( empty($args) )
        $args = func_get_args();

    do {
        foreach( (array) current($wp_filter[$tag]) as $the_ )
            if ( !is_null($the_['function']) ){
                $args[1] = $value;
                $value = call_user_func_array($the_['function'], array
+_slice($args, 1, (int) $the_['accepted_args']));
            }

    } while ( next($wp_filter[$tag]) !== false );

    array_pop( $wp_current_filter );

    return $value;
}
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My hope and the reason for my posting was, that someone already has written a module/function/... in Perl that accomplished this. It seems this is not the case.

Once again you just give up too easily. PHP is no harder than Perl. You're just being lazy.

sanitize_title
    applied to a post title by the sanitize_title function, after stri
+pping out HTML tags. 

wordpress/wp-includes/taxonomy.php:        $value = apply_filters("pre
+_term_$field", $value, $taxonomy);

wordpress/wp-includes/default-filters.php:$filters = array('pre_term_s
+lug');
wordpress/wp-includes/plugin.php:function apply_filters($tag, $value) 
+{
wordpress/wp-includes/formatting.php:function sanitize_file_name( $nam
+e ) { // Like sanitize_title, but with periods
wordpress/wp-includes/formatting.php:function sanitize_title($title, $
+fallback_title = '') {
wordpress/wp-includes/formatting.php:    $title = apply_filters('sanit
+ize_title', $title);
wordpress/wp-includes/taxonomy.php:        $args['query_var'] = saniti
+ze_title_with_dashes($args['query_var']);
wordpress/wp-includes/taxonomy.php:            $args['rewrite']['slug'
+] = sanitize_title_with_dashes($taxonomy);
wordpress/wp-includes/taxonomy.php:        $value = sanitize_title($va
+lue);
wordpress/wp-includes/taxonomy.php:        $slug = sanitize_title($slu
+g);
wordpress/wp-includes/taxonomy.php:    if ( '' === $slug = sanitize_ti
+tle($term) )
wordpress/wp-includes/taxonomy.php:        $slug = sanitize_title($nam
+e);
wordpress/wp-includes/taxonomy.php:        $slug = sanitize_title($slu
+g, $term_id);
wordpress/wp-includes/taxonomy.php:        $slug = sanitize_title($nam
+e);
wordpress/wp-includes/taxonomy.php:        $slug = sanitize_title($nam
+e, $term_id);

function add_filter($tag, $function_to_add, $priority = 10, $accepted_
+args = 1) {
    global $wp_filter, $merged_filters;

    $idx = _wp_filter_build_unique_id($tag, $function_to_add, $priorit
+y);
    $wp_filter[$tag][$priority][$idx] = array('function' => $function_
+to_add, 'accepted_args' => $accepted_args);
    unset( $merged_filters[ $tag ] );
    return true;
}



// Slugs
$filters = array('pre_term_slug');
foreach ( $filters as $filter ) {
    add_filter($filter, 'sanitize_title');
}

add_filter('sanitize_title', 'sanitize_title_with_dashes');


function sanitize_title_with_dashes($title) {
    $title = strip_tags($title);
    // Preserve escaped octets.
    $title = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $
+title);
    // Remove percent signs that are not part of an octet.
    $title = str_replace('%', '', $title);
    // Restore octets.
    $title = preg_replace('|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $
+title);

    $title = remove_accents($title);
    if (seems_utf8($title)) {
        if (function_exists('mb_strtolower')) {
            $title = mb_strtolower($title, 'UTF-8');
        }
        $title = utf8_uri_encode($title, 200);
    }

    $title = strtolower($title);
    $title = preg_replace('/&.+?;/', '', $title); // kill entities
    $title = preg_replace('/[^%a-z0-9 _-]/', '', $title);
    $title = preg_replace('/\s+/', '-', $title);
    $title = preg_replace('|-+|', '-', $title);
    $title = trim($title, '-');

    return $title;
}
[download]

http://www.w3schools.com/php/func_string_strip_tags.asp
http://www.php.net/preg_replace
http://www.php.net/strip_tags
http://www.php.net/trim
http://www.php.net/strtolower
WordPress › Support » How does WP remove accents from Polish characters?
http://codex.wordpress.org/Function_Reference_2.0.x

http://adambrown.info/p/wp_hooks/hook/sanitize_title?version=2.6&file=wp-includes/formatting.php
http://postedpost.com/2008/06/22/hack-wordpress-sanitize-title-function/
http://postedpost.com/2008/06/23/ultimate-wordpress-post-name-url-sanitize-solution/

> You're just being lazy.

In defense I can only say, that I'm not a good perl scripter too. :)

I'm really trying hard. I don't expect anybody to write this for me in case you fear I'm that sort of guy.

As far as I understand your posted code, sanitize_title_with_dashes is the function to look for. Finally some string manipulation. :)

Thanks for all the other helpful links. I'll have a look at it and will try to convert sanitize_title_with_dashes into perl code.

Cheers Klammer