Rarst asks: what magic turns pretty permalinks into query variables?

The setup:

• index.php
• wp-blog-header.php: wp();
• wp-includes/functions.php: function wp
• wp-includes/class-wp.php: function main
• wp-includes/class-wp.php: function parse_request
• $rewrite = $wp_rewrite->wp_rewrite_rules() (add bbPress)

The magic:

foreach ( $rewrite as $match => $query ) {
	if ( preg_match("#^$match#", $request_match, $matches) ) {
		// Got a match.
		$this->matched_rule = $match;
		break;
	}
}

The real voodoo is in creating the rewrite rules. Example: bbPress

• register_post_types
• register_taxonomies
• add_rewrite_tags
• generate_rewrite_rules

Exercise: optimize parse_request by restructuring the rules into a tree.

Nacin suggests: wp-hackers Skip Main Query

• the grand scheme of things (png, blog post)
• $wp->init()
• class freshlypressed_wp extends wp
• wp() calls $wp->main()
• $wp->main() calls $this->parse_request()
• $this is a freshlypressed_wp

Problems:

• Can’t extend a variable class (class my_wp extends $wp_class)
• No pluggable inheritance chaining
• No way for several plugins to cooperatively extend a class