Index: src/wp-includes/rewrite.php
===================================================================
--- src/wp-includes/rewrite.php	(revision 27218)
+++ src/wp-includes/rewrite.php	(working copy)
@@ -288,7 +288,14 @@
 function url_to_postid($url) {
 	global $wp_rewrite;
 
-	$url = apply_filters('url_to_postid', $url);
+	/**
+	 * Filter the URL that will be examined to determine a post ID.
+	 *
+	 * @since 2.2.0
+	 *
+	 * @param string $url The URL which will be searched.
+	 */
+	$url = apply_filters( 'url_to_postid', $url );
 
 	// First, check to see if there is a 'p=N' or 'page_id=N' to match against
 	if ( preg_match('#[?&](p|page_id|attachment_id)=(\d+)#', $url, $values) )	{
@@ -1558,36 +1565,105 @@
 		}
 		$registration_pages['.*wp-register.php$'] = $this->index . '?register=true'; // Deprecated
 
-		// Post
+		// Post rewrite rules.
 		$post_rewrite = $this->generate_rewrite_rules( $this->permalink_structure, EP_PERMALINK );
-		$post_rewrite = apply_filters('post_rewrite_rules', $post_rewrite);
 
-		// Date
+		/**
+		 * Filter rewrite rules used for "post" post type archives.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $post_rewrite The rewrite rules for the "post" post type.
+		 */
+		$post_rewrite = apply_filters( 'post_rewrite_rules', $post_rewrite );
+
+		// Date rewrite rules.
 		$date_rewrite = $this->generate_rewrite_rules($this->get_date_permastruct(), EP_DATE);
-		$date_rewrite = apply_filters('date_rewrite_rules', $date_rewrite);
 
-		// Root
+		/**
+		 * Filter rewrite rules used for date archives.
+		 *
+		 * Likely date archives would include /yyyy/, /yyyy/mm/, and /yyyy/mm/dd/.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $date_rewrite The rewrite rules for date archives.
+		 */
+		$date_rewrite = apply_filters( 'date_rewrite_rules', $date_rewrite );
+
+		// Root-level rewrite rules.
 		$root_rewrite = $this->generate_rewrite_rules($this->root . '/', EP_ROOT);
-		$root_rewrite = apply_filters('root_rewrite_rules', $root_rewrite);
 
-		// Comments
+		/**
+		 * Filter rewrite rules used for root-level archives.
+		 *
+		 * Likely root-level archives would include pagination rules for the homepage
+		 * as well as site-wide post feeds (e.g. /feed/, and /feed/atom/).
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $root_rewrite The root-level rewrite rules.
+		 */
+		$root_rewrite = apply_filters( 'root_rewrite_rules', $root_rewrite );
+
+		// Comments rewrite rules.
 		$comments_rewrite = $this->generate_rewrite_rules($this->root . $this->comments_base, EP_COMMENTS, false, true, true, false);
-		$comments_rewrite = apply_filters('comments_rewrite_rules', $comments_rewrite);
 
-		// Search
+		/**
+		 * Filter rewrite rules used for comment feed archives.
+		 *
+		 * Likely comments feed archives include /comments/feed/, and /comments/feed/atom/.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $comments_rewrite The rewrite rules for the site-wide comments feeds.
+		 */
+		$comments_rewrite = apply_filters( 'comments_rewrite_rules', $comments_rewrite );
+
+		// Search rewrite rules.
 		$search_structure = $this->get_search_permastruct();
 		$search_rewrite = $this->generate_rewrite_rules($search_structure, EP_SEARCH);
-		$search_rewrite = apply_filters('search_rewrite_rules', $search_rewrite);
 
-		// Authors
+		/**
+		 * Filter rewrite rules used for search archives.
+		 *
+		 * Likely search-related archives include /search/search+query/ as well as
+		 * pagination and feed paths for a search.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $search_rewrite The rewrite rules for search queries.
+		 */
+		$search_rewrite = apply_filters( 'search_rewrite_rules', $search_rewrite );
+
+		// Author rewrite rules.
 		$author_rewrite = $this->generate_rewrite_rules($this->get_author_permastruct(), EP_AUTHORS);
-		$author_rewrite = apply_filters('author_rewrite_rules', $author_rewrite);
 
-		// Pages
+		/**
+		 * Filter rewrite rules used for author archives.
+		 *
+		 * Likely author archives would inlcude /author/author-name/, as well as
+		 * pagination and feed paths for author archives.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $author_rewrite The rewrite rules for author archives.
+		 */
+		$author_rewrite = apply_filters( 'author_rewrite_rules', $author_rewrite );
+
+		// Pages rewrite rules.
 		$page_rewrite = $this->page_rewrite_rules();
-		$page_rewrite = apply_filters('page_rewrite_rules', $page_rewrite);
 
-		// Extra permastructs
+		/**
+		 * Filter rewrite rules used for "page" post type archives.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $page_rewrite The rewrite rules for the "page" post type.
+		 */
+		$page_rewrite = apply_filters( 'page_rewrite_rules', $page_rewrite );
+
+		// Extra permastructs.
 		foreach ( $this->extra_permastructs as $permastructname => $struct ) {
 			if ( is_array( $struct ) ) {
 				if ( count( $struct ) == 2 )
@@ -1598,9 +1674,29 @@
 				$rules = $this->generate_rewrite_rules( $struct );
 			}
 
-			$rules = apply_filters($permastructname . '_rewrite_rules', $rules);
-			if ( 'post_tag' == $permastructname )
-				$rules = apply_filters('tag_rewrite_rules', $rules);
+			/**
+			 * Filter rewrite rules used for individual permastructs.
+			 *
+			 * The dynamic portion of the hook name, $permastructname, refers
+			 * to the name of the registered permastruct, e.g. 'post_tag' (tags),
+			 * 'category' (categories), etc.
+			 *
+			 * @since 3.1.0
+			 *
+			 * @param array $rules The rewrite rules generated for the current permastruct.
+			 */
+			$rules = apply_filters( $permastructname . '_rewrite_rules', $rules );
+			if ( 'post_tag' == $permastructname ) {
+				/**
+				 * Filter rewrite rules used specifically for Tags.
+				 *
+				 * @since 2.3.0
+				 * @deprecated 3.1.0 Use 'post_tag_rewrite_rules' instead
+				 *
+				 * @param array $rules The rewrite rules generated for tags.
+				 */
+				$rules = apply_filters( 'tag_rewrite_rules', $rules );
+			}
 
 			$this->extra_rules_top = array_merge($this->extra_rules_top, $rules);
 		}
@@ -1611,9 +1707,24 @@
 		else
 			$this->rules = array_merge($this->extra_rules_top, $robots_rewrite, $deprecated_files, $registration_pages, $root_rewrite, $comments_rewrite, $search_rewrite,  $author_rewrite, $date_rewrite, $post_rewrite, $page_rewrite, $this->extra_rules);
 
-		do_action_ref_array('generate_rewrite_rules', array(&$this));
-		$this->rules = apply_filters('rewrite_rules_array', $this->rules);
+		/**
+		 * Fires after the rewrite rules are generated.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param WP_Rewrite $this Current WP_Rewrite instance, passed by reference.
+		 */
+		do_action_ref_array( 'generate_rewrite_rules', array( &$this ) );
 
+		/**
+		 * Filter the full set of generated rewrite rules.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param array $this->rules The compiled array of rewrite rules.
+		 */
+		$this->rules = apply_filters( 'rewrite_rules_array', $this->rules );
+
 		return $this->rules;
 	}
 
@@ -1720,9 +1831,25 @@
 
 		$rules .= "</IfModule>\n";
 
-		$rules = apply_filters('mod_rewrite_rules', $rules);
-		$rules = apply_filters('rewrite_rules', $rules);  // Deprecated
+		/**
+		 * Filter rewrite rules formatted for output to a mod_rewrite .htaccess file.
+		 *
+		 * @since 1.5.0
+		 *
+		 * @param string $rules mod_rewrite Rewrite rules formatted for .htaccess.
+		 */
+		$rules = apply_filters( 'mod_rewrite_rules', $rules );
 
+		/**
+		 * Filter rewrite rules formatted for output to a mod_rewrite .htaccess file.
+		 *
+		 * @since 1.5.0
+		 * @deprecated 1.5.0 Use the mod_rewrite_rules filter instead.
+		 *
+		 * @param string $rules mod_rewrite Rewrite rules formatted for .htaccess.
+		 */
+		$rules = apply_filters( 'rewrite_rules', $rules );  // Deprecated
+
 		return $rules;
 	}
 
@@ -1767,7 +1894,14 @@
 </configuration>';
 		}
 
-		$rules = apply_filters('iis7_url_rewrite_rules', $rules);
+		/**
+		 * Filter rewrite rules formatted for output to an IIS web.config file.
+		 *
+		 * @since 2.8.0
+		 *
+		 * @param string $rules Rewrite rules formatted for IIS web.config.
+		 */
+		$rules = apply_filters( 'iis7_url_rewrite_rules', $rules );
 
 		return $rules;
 	}
@@ -1910,10 +2044,12 @@
 		 * A "hard" flush updates .htaccess (Apache) or web.config (IIS).
 		 *
 		 * @since 3.7.0
-		 * @param bool $hard Defaults to true.
+		 *
+		 * @param bool $hard Whether to flush rewrite rules "hard". Default true.
 		 */
-		if ( ! $hard || ! apply_filters( 'flush_rewrite_rules_hard', true ) )
+		if ( ! $hard || ! apply_filters( 'flush_rewrite_rules_hard', true ) ) {
 			return;
+		}
 		if ( function_exists( 'save_mod_rewrite_rules' ) )
 			save_mod_rewrite_rules();
 		if ( function_exists( 'iis7_save_url_rewrite_rules' ) )
@@ -1972,7 +2108,16 @@
 			$old_permalink_structure = $this->permalink_structure;
 			update_option('permalink_structure', $permalink_structure);
 			$this->init();
-			do_action('permalink_structure_changed', $old_permalink_structure, $permalink_structure);
+
+			/**
+			 * Fires after the permalink structure is updated.
+			 *
+			 * @since 2.8.0
+			 *
+			 * @param string $old_permalink_structure The previous permalink structure.
+			 * @param string $permalink_structure     The new permalink structure.
+			 */
+			do_action( 'permalink_structure_changed', $old_permalink_structure, $permalink_structure );
 		}
 	}