X-Git-Url: https://scripts.mit.edu/gitweb/autoinstalls/wordpress.git/blobdiff_plain/d3b1ea255664edd2deef17f900a655613d20820d..073c5ed6408e2f00dc1863b463fe205467628905:/wp-includes/category-template.php

diff --git a/wp-includes/category-template.php b/wp-includes/category-template.php
index 61f2faf1..7063c2d4 100644
--- a/wp-includes/category-template.php
+++ b/wp-includes/category-template.php
@@ -1,42 +1,31 @@
 <?php
 /**
- * Category Template Tags and API.
+ * Taxonomy API: Core category-specific template tags
  *
  * @package WordPress
  * @subpackage Template
+ * @since 1.2.0
  */
 
 /**
  * Retrieve category link URL.
  *
  * @since 1.0.0
- * @uses apply_filters() Calls 'category_link' filter on category link and category ID.
+ * @see get_term_link()
  *
- * @param int $category_id Category ID.
- * @return string
+ * @param int|object $category Category ID or object.
+ * @return string Link on success, empty string if category does not exist.
  */
-function get_category_link( $category_id ) {
-	global $wp_rewrite;
-	$catlink = $wp_rewrite->get_category_permastruct();
+function get_category_link( $category ) {
+	if ( ! is_object( $category ) )
+		$category = (int) $category;
 
-	if ( empty( $catlink ) ) {
-		$file = get_option( 'home' ) . '/';
-		$catlink = $file . '?cat=' . $category_id;
-	} else {
-		$category = &get_category( $category_id );
-		if ( is_wp_error( $category ) )
-			return $category;
-		$category_nicename = $category->slug;
+	$category = get_term_link( $category, 'category' );
 
-		if ( $category->parent == $category_id ) // recursive recursion
-			$category->parent = 0;
-		elseif ($category->parent != 0 )
-			$category_nicename = get_category_parents( $category->parent, false, '/', true ) . $category_nicename;
+	if ( is_wp_error( $category ) )
+		return '';
 
-		$catlink = str_replace( '%category%', $category_nicename, $catlink );
-		$catlink = get_option( 'home' ) . user_trailingslashit( $catlink, 'category' );
-	}
-	return apply_filters( 'category_link', $catlink, $category_id );
+	return $category;
 }
 
 /**
@@ -49,18 +38,18 @@ function get_category_link( $category_id ) {
  * @param string $separator Optional, default is '/'. How to separate categories.
  * @param bool $nicename Optional, default is false. Whether to use nice name for display.
  * @param array $visited Optional. Already linked to categories to prevent duplicates.
- * @return string
+ * @return string|WP_Error A list of category parents on success, WP_Error on failure.
  */
 function get_category_parents( $id, $link = false, $separator = '/', $nicename = false, $visited = array() ) {
 	$chain = '';
-	$parent = &get_category( $id );
+	$parent = get_term( $id, 'category' );
 	if ( is_wp_error( $parent ) )
 		return $parent;
 
 	if ( $nicename )
 		$name = $parent->slug;
 	else
-		$name = $parent->cat_name;
+		$name = $parent->name;
 
 	if ( $parent->parent && ( $parent->parent != $parent->term_id ) && !in_array( $parent->parent, $visited ) ) {
 		$visited[] = $parent->parent;
@@ -68,7 +57,7 @@ function get_category_parents( $id, $link = false, $separator = '/', $nicename =
 	}
 
 	if ( $link )
-		$chain .= '<a href="' . get_category_link( $parent->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $parent->cat_name ) . '">'.$name.'</a>' . $separator;
+		$chain .= '<a href="' . esc_url( get_category_link( $parent->term_id ) ) . '">'.$name.'</a>' . $separator;
 	else
 		$chain .= $name.$separator;
 	return $chain;
@@ -77,35 +66,37 @@ function get_category_parents( $id, $link = false, $separator = '/', $nicename =
 /**
  * Retrieve post categories.
  *
+ * This tag may be used outside The Loop by passing a post id as the parameter.
+ *
+ * Note: This function only returns results from the default "category" taxonomy.
+ * For custom taxonomies use get_the_terms().
+ *
  * @since 0.71
- * @uses $post
  *
  * @param int $id Optional, default to current post ID. The post ID.
- * @return array
+ * @return array Array of WP_Term objects, one for each category assigned to the post.
  */
 function get_the_category( $id = false ) {
-	global $post;
-
-	$id = (int) $id;
-	if ( !$id )
-		$id = (int) $post->ID;
-
-	$categories = get_object_term_cache( $id, 'category' );
-	if ( false === $categories ) {
-		$categories = wp_get_object_terms( $id, 'category' );
-		wp_cache_add($id, $categories, 'category_relationships');
-	}
-
-	if ( !empty( $categories ) )
-		usort( $categories, '_usort_terms_by_name' );
-	else
+	$categories = get_the_terms( $id, 'category' );
+	if ( ! $categories || is_wp_error( $categories ) )
 		$categories = array();
 
-	foreach ( (array) array_keys( $categories ) as $key ) {
+	$categories = array_values( $categories );
+
+	foreach ( array_keys( $categories ) as $key ) {
 		_make_cat_compat( $categories[$key] );
 	}
 
-	return $categories;
+	/**
+	 * Filters the array of categories to return for a post.
+	 *
+	 * @since 3.1.0
+	 * @since 4.4.0 Added `$id` parameter.
+	 *
+	 * @param array $categories An array of categories to return for the post.
+	 * @param int   $id         ID of the post.
+	 */
+	return apply_filters( 'get_the_categories', $categories, $id );
 }
 
 /**
@@ -153,14 +144,16 @@ function _usort_terms_by_ID( $a, $b ) {
  * @since 0.71
  *
  * @param int $cat_ID Category ID.
- * @return string Category name.
+ * @return string|WP_Error Category name on success, WP_Error on failure.
  */
 function get_the_category_by_ID( $cat_ID ) {
 	$cat_ID = (int) $cat_ID;
-	$category = &get_category( $cat_ID );
+	$category = get_term( $cat_ID, 'category' );
+
 	if ( is_wp_error( $category ) )
 		return $category;
-	return $category->name;
+
+	return ( $category ) ? $category->name : '';
 }
 
 /**
@@ -168,6 +161,8 @@ function get_the_category_by_ID( $cat_ID ) {
  *
  * @since 1.5.1
  *
+ * @global WP_Rewrite $wp_rewrite
+ *
  * @param string $separator Optional, default is empty string. Separator for between the categories.
  * @param string $parents Optional. How to display the parents.
  * @param int $post_id Optional. Post ID to retrieve categories.
@@ -175,9 +170,26 @@ function get_the_category_by_ID( $cat_ID ) {
  */
 function get_the_category_list( $separator = '', $parents='', $post_id = false ) {
 	global $wp_rewrite;
-	$categories = get_the_category( $post_id );
-	if ( empty( $categories ) )
+	if ( ! is_object_in_taxonomy( get_post_type( $post_id ), 'category' ) ) {
+		/** This filter is documented in wp-includes/category-template.php */
+		return apply_filters( 'the_category', '', $separator, $parents );
+	}
+
+	/**
+	 * Filters the categories before building the category list.
+	 *
+	 * @since 4.4.0
+	 *
+	 * @param array    $categories An array of the post's categories.
+	 * @param int|bool $post_id    ID of the post we're retrieving categories for. When `false`, we assume the
+	 *                             current post in the loop.
+	 */
+	$categories = apply_filters( 'the_category_list', get_the_category( $post_id ), $post_id );
+
+	if ( empty( $categories ) ) {
+		/** This filter is documented in wp-includes/category-template.php */
 		return apply_filters( 'the_category', __( 'Uncategorized' ), $separator, $parents );
+	}
 
 	$rel = ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) ? 'rel="category tag"' : 'rel="category"';
 
@@ -190,17 +202,17 @@ function get_the_category_list( $separator = '', $parents='', $post_id = false )
 				case 'multiple':
 					if ( $category->parent )
 						$thelist .= get_category_parents( $category->parent, true, $separator );
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->name.'</a></li>';
+					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name.'</a></li>';
 					break;
 				case 'single':
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>';
+					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '"  ' . $rel . '>';
 					if ( $category->parent )
 						$thelist .= get_category_parents( $category->parent, false, $separator );
 					$thelist .= $category->name.'</a></li>';
 					break;
 				case '':
 				default:
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->cat_name.'</a></li>';
+					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name.'</a></li>';
 			}
 		}
 		$thelist .= '</ul>';
@@ -208,30 +220,40 @@ function get_the_category_list( $separator = '', $parents='', $post_id = false )
 		$i = 0;
 		foreach ( $categories as $category ) {
 			if ( 0 < $i )
-				$thelist .= $separator . ' ';
+				$thelist .= $separator;
 			switch ( strtolower( $parents ) ) {
 				case 'multiple':
 					if ( $category->parent )
 						$thelist .= get_category_parents( $category->parent, true, $separator );
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->cat_name.'</a>';
+					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name.'</a>';
 					break;
 				case 'single':
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>';
+					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>';
 					if ( $category->parent )
 						$thelist .= get_category_parents( $category->parent, false, $separator );
-					$thelist .= "$category->cat_name</a>";
+					$thelist .= "$category->name</a>";
 					break;
 				case '':
 				default:
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->name.'</a>';
+					$thelist .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" ' . $rel . '>' . $category->name.'</a>';
 			}
 			++$i;
 		}
 	}
+
+	/**
+	 * Filters the category or list of categories.
+	 *
+	 * @since 1.2.0
+	 *
+	 * @param array  $thelist   List of categories for the current post.
+	 * @param string $separator Separator used between the categories.
+	 * @param string $parents   How to display the category parents. Accepts 'multiple',
+	 *                          'single', or empty.
+	 */
 	return apply_filters( 'the_category', $thelist, $separator, $parents );
 }
 
-
 /**
  * Check if the current post in within any of the given categories.
  *
@@ -246,29 +268,15 @@ function get_the_category_list( $separator = '', $parents='', $post_id = false )
  *
  * @since 1.2.0
  *
- * @uses is_object_in_term()
- *
- * @param int|string|array $category. Category ID, name or slug, or array of said.
- * @param int|post object Optional.  Post to check instead of the current post. @since 2.7.0
+ * @param int|string|array $category Category ID, name or slug, or array of said.
+ * @param int|object $post Optional. Post to check instead of the current post. (since 2.7.0)
  * @return bool True if the current post is in any of the given categories.
  */
-function in_category( $category, $_post = null ) {
+function in_category( $category, $post = null ) {
 	if ( empty( $category ) )
 		return false;
 
-	if ( $_post ) {
-		$_post = get_post( $_post );
-	} else {
-		$_post =& $GLOBALS['post'];
-	}
-
-	if ( !$_post )
-		return false;
-
-	$r = is_object_in_term( $_post->ID, 'category', $category );
-	if ( is_wp_error( $r ) )
-		return false;
-	return $r;
+	return has_category( $category, $post );
 }
 
 /**
@@ -299,195 +307,380 @@ function category_description( $category = 0 ) {
 /**
  * Display or retrieve the HTML dropdown list of categories.
  *
- * The list of arguments is below:
- *     'show_option_all' (string) - Text to display for showing all categories.
- *     'show_option_none' (string) - Text to display for showing no categories.
- *     'orderby' (string) default is 'ID' - What column to use for ordering the
- * categories.
- *     'order' (string) default is 'ASC' - What direction to order categories.
- *     'show_last_update' (bool|int) default is 0 - See {@link get_categories()}
- *     'show_count' (bool|int) default is 0 - Whether to show how many posts are
- * in the category.
- *     'hide_empty' (bool|int) default is 1 - Whether to hide categories that
- * don't have any posts attached to them.
- *     'child_of' (int) default is 0 - See {@link get_categories()}.
- *     'exclude' (string) - See {@link get_categories()}.
- *     'echo' (bool|int) default is 1 - Whether to display or retrieve content.
- *     'depth' (int) - The max depth.
- *     'tab_index' (int) - Tab index for select element.
- *     'name' (string) - The name attribute value for selected element.
- *     'class' (string) - The class attribute value for selected element.
- *     'selected' (int) - Which category ID is selected.
- *
  * The 'hierarchical' argument, which is disabled by default, will override the
  * depth argument, unless it is true. When the argument is false, it will
  * display all of the categories. When it is enabled it will use the value in
  * the 'depth' argument.
  *
  * @since 2.1.0
- *
- * @param string|array $args Optional. Override default arguments.
+ * @since 4.2.0 Introduced the `value_field` argument.
+ * @since 4.6.0 Introduced the `required` argument.
+ *
+ * @param string|array $args {
+ *     Optional. Array or string of arguments to generate a categories drop-down element.
+ *
+ *     @type string       $show_option_all   Text to display for showing all categories. Default empty.
+ *     @type string       $show_option_none  Text to display for showing no categories. Default empty.
+ *     @type string       $option_none_value Value to use when no category is selected. Default empty.
+ *     @type string       $orderby           Which column to use for ordering categories. See get_terms() for a list
+ *                                           of accepted values. Default 'id' (term_id).
+ *     @type string       $order             Whether to order terms in ascending or descending order. Accepts 'ASC'
+ *                                           or 'DESC'. Default 'ASC'.
+ *     @type bool         $pad_counts        See get_terms() for an argument description. Default false.
+ *     @type bool|int     $show_count        Whether to include post counts. Accepts 0, 1, or their bool equivalents.
+ *                                           Default 0.
+ *     @type bool|int     $hide_empty        Whether to hide categories that don't have any posts. Accepts 0, 1, or
+ *                                           their bool equivalents. Default 1.
+ *     @type int          $child_of          Term ID to retrieve child terms of. See get_terms(). Default 0.
+ *     @type array|string $exclude           Array or comma/space-separated string of term ids to exclude.
+ *                                           If `$include` is non-empty, `$exclude` is ignored. Default empty array.
+ *     @type bool|int     $echo              Whether to echo or return the generated markup. Accepts 0, 1, or their
+ *                                           bool equivalents. Default 1.
+ *     @type bool|int     $hierarchical      Whether to traverse the taxonomy hierarchy. Accepts 0, 1, or their bool
+ *                                           equivalents. Default 0.
+ *     @type int          $depth             Maximum depth. Default 0.
+ *     @type int          $tab_index         Tab index for the select element. Default 0 (no tabindex).
+ *     @type string       $name              Value for the 'name' attribute of the select element. Default 'cat'.
+ *     @type string       $id                Value for the 'id' attribute of the select element. Defaults to the value
+ *                                           of `$name`.
+ *     @type string       $class             Value for the 'class' attribute of the select element. Default 'postform'.
+ *     @type int|string   $selected          Value of the option that should be selected. Default 0.
+ *     @type string       $value_field       Term field that should be used to populate the 'value' attribute
+ *                                           of the option elements. Accepts any valid term field: 'term_id', 'name',
+ *                                           'slug', 'term_group', 'term_taxonomy_id', 'taxonomy', 'description',
+ *                                           'parent', 'count'. Default 'term_id'.
+ *     @type string|array $taxonomy          Name of the category or categories to retrieve. Default 'category'.
+ *     @type bool         $hide_if_empty     True to skip generating markup if no categories are found.
+ *                                           Default false (create select element even if no categories are found).
+ *     @type bool         $required          Whether the `<select>` element should have the HTML5 'required' attribute.
+ *                                           Default false.
+ * }
  * @return string HTML content only if 'echo' argument is 0.
  */
 function wp_dropdown_categories( $args = '' ) {
 	$defaults = array(
-		'show_option_all' => '', 'show_option_none' => '',
-		'orderby' => 'id', 'order' => 'ASC',
-		'show_last_update' => 0, 'show_count' => 0,
-		'hide_empty' => 1, 'child_of' => 0,
-		'exclude' => '', 'echo' => 1,
-		'selected' => 0, 'hierarchical' => 0,
-		'name' => 'cat', 'class' => 'postform',
-		'depth' => 0, 'tab_index' => 0
+		'show_option_all'   => '',
+		'show_option_none'  => '',
+		'orderby'           => 'id',
+		'order'             => 'ASC',
+		'show_count'        => 0,
+		'hide_empty'        => 1,
+		'child_of'          => 0,
+		'exclude'           => '',
+		'echo'              => 1,
+		'selected'          => 0,
+		'hierarchical'      => 0,
+		'name'              => 'cat',
+		'id'                => '',
+		'class'             => 'postform',
+		'depth'             => 0,
+		'tab_index'         => 0,
+		'taxonomy'          => 'category',
+		'hide_if_empty'     => false,
+		'option_none_value' => -1,
+		'value_field'       => 'term_id',
+		'required'          => false,
 	);
 
 	$defaults['selected'] = ( is_category() ) ? get_query_var( 'cat' ) : 0;
 
+	// Back compat.
+	if ( isset( $args['type'] ) && 'link' == $args['type'] ) {
+		/* translators: 1: "type => link", 2: "taxonomy => link_category" alternative */
+		_deprecated_argument( __FUNCTION__, '3.0.0',
+			sprintf( __( '%1$s is deprecated. Use %2$s instead.' ),
+				'<code>type => link</code>',
+				'<code>taxonomy => link_category</code>'
+			)
+		);
+		$args['taxonomy'] = 'link_category';
+	}
+
 	$r = wp_parse_args( $args, $defaults );
-	$r['include_last_update_time'] = $r['show_last_update'];
-	extract( $r );
+	$option_none_value = $r['option_none_value'];
+
+	if ( ! isset( $r['pad_counts'] ) && $r['show_count'] && $r['hierarchical'] ) {
+		$r['pad_counts'] = true;
+	}
+
+	$tab_index = $r['tab_index'];
 
 	$tab_index_attribute = '';
-	if ( (int) $tab_index > 0 )
+	if ( (int) $tab_index > 0 ) {
 		$tab_index_attribute = " tabindex=\"$tab_index\"";
+	}
 
-	$categories = get_categories( $r );
+	// Avoid clashes with the 'name' param of get_terms().
+	$get_terms_args = $r;
+	unset( $get_terms_args['name'] );
+	$categories = get_terms( $r['taxonomy'], $get_terms_args );
+
+	$name = esc_attr( $r['name'] );
+	$class = esc_attr( $r['class'] );
+	$id = $r['id'] ? esc_attr( $r['id'] ) : $name;
+	$required = $r['required'] ? 'required' : '';
+
+	if ( ! $r['hide_if_empty'] || ! empty( $categories ) ) {
+		$output = "<select $required name='$name' id='$id' class='$class' $tab_index_attribute>\n";
+	} else {
+		$output = '';
+	}
+	if ( empty( $categories ) && ! $r['hide_if_empty'] && ! empty( $r['show_option_none'] ) ) {
+
+		/**
+		 * Filters a taxonomy drop-down display element.
+		 *
+		 * A variety of taxonomy drop-down display elements can be modified
+		 * just prior to display via this filter. Filterable arguments include
+		 * 'show_option_none', 'show_option_all', and various forms of the
+		 * term name.
+		 *
+		 * @since 1.2.0
+		 *
+		 * @see wp_dropdown_categories()
+		 *
+		 * @param string $element Taxonomy element to list.
+		 */
+		$show_option_none = apply_filters( 'list_cats', $r['show_option_none'] );
+		$output .= "\t<option value='" . esc_attr( $option_none_value ) . "' selected='selected'>$show_option_none</option>\n";
+	}
 
-	$output = '';
 	if ( ! empty( $categories ) ) {
-		$output = "<select name='$name' id='$name' class='$class' $tab_index_attribute>\n";
 
-		if ( $show_option_all ) {
-			$show_option_all = apply_filters( 'list_cats', $show_option_all );
+		if ( $r['show_option_all'] ) {
+
+			/** This filter is documented in wp-includes/category-template.php */
+			$show_option_all = apply_filters( 'list_cats', $r['show_option_all'] );
 			$selected = ( '0' === strval($r['selected']) ) ? " selected='selected'" : '';
 			$output .= "\t<option value='0'$selected>$show_option_all</option>\n";
 		}
 
-		if ( $show_option_none ) {
-			$show_option_none = apply_filters( 'list_cats', $show_option_none );
-			$selected = ( '-1' === strval($r['selected']) ) ? " selected='selected'" : '';
-			$output .= "\t<option value='-1'$selected>$show_option_none</option>\n";
+		if ( $r['show_option_none'] ) {
+
+			/** This filter is documented in wp-includes/category-template.php */
+			$show_option_none = apply_filters( 'list_cats', $r['show_option_none'] );
+			$selected = selected( $option_none_value, $r['selected'], false );
+			$output .= "\t<option value='" . esc_attr( $option_none_value ) . "'$selected>$show_option_none</option>\n";
 		}
 
-		if ( $hierarchical )
+		if ( $r['hierarchical'] ) {
 			$depth = $r['depth'];  // Walk the full depth.
-		else
+		} else {
 			$depth = -1; // Flat.
-
+		}
 		$output .= walk_category_dropdown_tree( $categories, $depth, $r );
-		$output .= "</select>\n";
 	}
 
-	$output = apply_filters( 'wp_dropdown_cats', $output );
-
-	if ( $echo )
+	if ( ! $r['hide_if_empty'] || ! empty( $categories ) ) {
+		$output .= "</select>\n";
+	}
+	/**
+	 * Filters the taxonomy drop-down output.
+	 *
+	 * @since 2.1.0
+	 *
+	 * @param string $output HTML output.
+	 * @param array  $r      Arguments used to build the drop-down.
+	 */
+	$output = apply_filters( 'wp_dropdown_cats', $output, $r );
+
+	if ( $r['echo'] ) {
 		echo $output;
-
+	}
 	return $output;
 }
 
 /**
  * Display or retrieve the HTML list of categories.
  *
- * The list of arguments is below:
- *     'show_option_all' (string) - Text to display for showing all categories.
- *     'orderby' (string) default is 'ID' - What column to use for ordering the
- * categories.
- *     'order' (string) default is 'ASC' - What direction to order categories.
- *     'show_last_update' (bool|int) default is 0 - See {@link
- * walk_category_dropdown_tree()}
- *     'show_count' (bool|int) default is 0 - Whether to show how many posts are
- * in the category.
- *     'hide_empty' (bool|int) default is 1 - Whether to hide categories that
- * don't have any posts attached to them.
- *     'use_desc_for_title' (bool|int) default is 1 - Whether to use the
- * description instead of the category title.
- *     'feed' - See {@link get_categories()}.
- *     'feed_type' - See {@link get_categories()}.
- *     'feed_image' - See {@link get_categories()}.
- *     'child_of' (int) default is 0 - See {@link get_categories()}.
- *     'exclude' (string) - See {@link get_categories()}.
- *     'exclude_tree' (string) - See {@link get_categories()}.
- *     'echo' (bool|int) default is 1 - Whether to display or retrieve content.
- *     'current_category' (int) - See {@link get_categories()}.
- *     'hierarchical' (bool) - See {@link get_categories()}.
- *     'title_li' (string) - See {@link get_categories()}.
- *     'depth' (int) - The max depth.
- *
  * @since 2.1.0
- *
- * @param string|array $args Optional. Override default arguments.
- * @return string HTML content only if 'echo' argument is 0.
+ * @since 4.4.0 Introduced the `hide_title_if_empty` and `separator` arguments. The `current_category` argument was modified to
+ *              optionally accept an array of values.
+ *
+ * @param string|array $args {
+ *     Array of optional arguments.
+ *
+ *     @type int          $child_of              Term ID to retrieve child terms of. See get_terms(). Default 0.
+ *     @type int|array    $current_category      ID of category, or array of IDs of categories, that should get the
+ *                                               'current-cat' class. Default 0.
+ *     @type int          $depth                 Category depth. Used for tab indentation. Default 0.
+ *     @type bool|int     $echo                  True to echo markup, false to return it. Default 1.
+ *     @type array|string $exclude               Array or comma/space-separated string of term IDs to exclude.
+ *                                               If `$hierarchical` is true, descendants of `$exclude` terms will also
+ *                                               be excluded; see `$exclude_tree`. See get_terms().
+ *                                               Default empty string.
+ *     @type array|string $exclude_tree          Array or comma/space-separated string of term IDs to exclude, along
+ *                                               with their descendants. See get_terms(). Default empty string.
+ *     @type string       $feed                  Text to use for the feed link. Default 'Feed for all posts filed
+ *                                               under [cat name]'.
+ *     @type string       $feed_image            URL of an image to use for the feed link. Default empty string.
+ *     @type string       $feed_type             Feed type. Used to build feed link. See get_term_feed_link().
+ *                                               Default empty string (default feed).
+ *     @type bool|int     $hide_empty            Whether to hide categories that don't have any posts attached to them.
+ *                                               Default 1.
+ *     @type bool         $hide_title_if_empty   Whether to hide the `$title_li` element if there are no terms in
+ *                                               the list. Default false (title will always be shown).
+ *     @type bool         $hierarchical          Whether to include terms that have non-empty descendants.
+ *                                               See get_terms(). Default true.
+ *     @type string       $order                 Which direction to order categories. Accepts 'ASC' or 'DESC'.
+ *                                               Default 'ASC'.
+ *     @type string       $orderby               The column to use for ordering categories. Default 'ID'.
+ *     @type string       $separator             Separator between links. Default '<br />'.
+ *     @type bool|int     $show_count            Whether to show how many posts are in the category. Default 0.
+ *     @type string       $show_option_all       Text to display for showing all categories. Default empty string.
+ *     @type string       $show_option_none      Text to display for the 'no categories' option.
+ *                                               Default 'No categories'.
+ *     @type string       $style                 The style used to display the categories list. If 'list', categories
+ *                                               will be output as an unordered list. If left empty or another value,
+ *                                               categories will be output separated by `<br>` tags. Default 'list'.
+ *     @type string       $taxonomy              Taxonomy name. Default 'category'.
+ *     @type string       $title_li              Text to use for the list title `<li>` element. Pass an empty string
+ *                                               to disable. Default 'Categories'.
+ *     @type bool|int     $use_desc_for_title    Whether to use the category description as the title attribute.
+ *                                               Default 1.
+ * }
+ * @return false|string HTML content only if 'echo' argument is 0.
  */
 function wp_list_categories( $args = '' ) {
 	$defaults = array(
-		'show_option_all' => '', 'orderby' => 'name',
-		'order' => 'ASC', 'show_last_update' => 0,
-		'style' => 'list', 'show_count' => 0,
-		'hide_empty' => 1, 'use_desc_for_title' => 1,
-		'child_of' => 0, 'feed' => '', 'feed_type' => '',
-		'feed_image' => '', 'exclude' => '', 'exclude_tree' => '', 'current_category' => 0,
-		'hierarchical' => true, 'title_li' => __( 'Categories' ),
-		'echo' => 1, 'depth' => 0
+		'child_of'            => 0,
+		'current_category'    => 0,
+		'depth'               => 0,
+		'echo'                => 1,
+		'exclude'             => '',
+		'exclude_tree'        => '',
+		'feed'                => '',
+		'feed_image'          => '',
+		'feed_type'           => '',
+		'hide_empty'          => 1,
+		'hide_title_if_empty' => false,
+		'hierarchical'        => true,
+		'order'               => 'ASC',
+		'orderby'             => 'name',
+		'separator'           => '<br />',
+		'show_count'          => 0,
+		'show_option_all'     => '',
+		'show_option_none'    => __( 'No categories' ),
+		'style'               => 'list',
+		'taxonomy'            => 'category',
+		'title_li'            => __( 'Categories' ),
+		'use_desc_for_title'  => 1,
 	);
 
 	$r = wp_parse_args( $args, $defaults );
 
-	if ( !isset( $r['pad_counts'] ) && $r['show_count'] && $r['hierarchical'] ) {
+	if ( !isset( $r['pad_counts'] ) && $r['show_count'] && $r['hierarchical'] )
 		$r['pad_counts'] = true;
-	}
-
-	if ( isset( $r['show_date'] ) ) {
-		$r['include_last_update_time'] = $r['show_date'];
-	}
 
+	// Descendants of exclusions should be excluded too.
 	if ( true == $r['hierarchical'] ) {
-		$r['exclude_tree'] = $r['exclude'];
+		$exclude_tree = array();
+
+		if ( $r['exclude_tree'] ) {
+			$exclude_tree = array_merge( $exclude_tree, wp_parse_id_list( $r['exclude_tree'] ) );
+		}
+
+		if ( $r['exclude'] ) {
+			$exclude_tree = array_merge( $exclude_tree, wp_parse_id_list( $r['exclude'] ) );
+		}
+
+		$r['exclude_tree'] = $exclude_tree;
 		$r['exclude'] = '';
 	}
 
-	extract( $r );
+	if ( ! isset( $r['class'] ) )
+		$r['class'] = ( 'category' == $r['taxonomy'] ) ? 'categories' : $r['taxonomy'];
+
+	if ( ! taxonomy_exists( $r['taxonomy'] ) ) {
+		return false;
+	}
+
+	$show_option_all = $r['show_option_all'];
+	$show_option_none = $r['show_option_none'];
 
 	$categories = get_categories( $r );
 
 	$output = '';
-	if ( $title_li && 'list' == $style )
-			$output = '<li class="categories">' . $r['title_li'] . '<ul>';
-
+	if ( $r['title_li'] && 'list' == $r['style'] && ( ! empty( $categories ) || ! $r['hide_title_if_empty'] ) ) {
+		$output = '<li class="' . esc_attr( $r['class'] ) . '">' . $r['title_li'] . '<ul>';
+	}
 	if ( empty( $categories ) ) {
-		if ( 'list' == $style )
-			$output .= '<li>' . __( "No categories" ) . '</li>';
-		else
-			$output .= __( "No categories" );
+		if ( ! empty( $show_option_none ) ) {
+			if ( 'list' == $r['style'] ) {
+				$output .= '<li class="cat-item-none">' . $show_option_none . '</li>';
+			} else {
+				$output .= $show_option_none;
+			}
+		}
 	} else {
-		global $wp_query;
+		if ( ! empty( $show_option_all ) ) {
+
+			$posts_page = '';
+
+			// For taxonomies that belong only to custom post types, point to a valid archive.
+			$taxonomy_object = get_taxonomy( $r['taxonomy'] );
+			if ( ! in_array( 'post', $taxonomy_object->object_type ) && ! in_array( 'page', $taxonomy_object->object_type ) ) {
+				foreach ( $taxonomy_object->object_type as $object_type ) {
+					$_object_type = get_post_type_object( $object_type );
+
+					// Grab the first one.
+					if ( ! empty( $_object_type->has_archive ) ) {
+						$posts_page = get_post_type_archive_link( $object_type );
+						break;
+					}
+				}
+			}
 
-		if( !empty( $show_option_all ) )
-			if ( 'list' == $style )
-				$output .= '<li><a href="' .  get_bloginfo( 'url' )  . '">' . $show_option_all . '</a></li>';
-			else
-				$output .= '<a href="' .  get_bloginfo( 'url' )  . '">' . $show_option_all . '</a>';
+			// Fallback for the 'All' link is the posts page.
+			if ( ! $posts_page ) {
+				if ( 'page' == get_option( 'show_on_front' ) && get_option( 'page_for_posts' ) ) {
+					$posts_page = get_permalink( get_option( 'page_for_posts' ) );
+				} else {
+					$posts_page = home_url( '/' );
+				}
+			}
 
-		if ( empty( $r['current_category'] ) && is_category() )
-			$r['current_category'] = $wp_query->get_queried_object_id();
+			$posts_page = esc_url( $posts_page );
+			if ( 'list' == $r['style'] ) {
+				$output .= "<li class='cat-item-all'><a href='$posts_page'>$show_option_all</a></li>";
+			} else {
+				$output .= "<a href='$posts_page'>$show_option_all</a>";
+			}
+		}
+
+		if ( empty( $r['current_category'] ) && ( is_category() || is_tax() || is_tag() ) ) {
+			$current_term_object = get_queried_object();
+			if ( $current_term_object && $r['taxonomy'] === $current_term_object->taxonomy ) {
+				$r['current_category'] = get_queried_object_id();
+			}
+		}
 
-		if ( $hierarchical )
+		if ( $r['hierarchical'] ) {
 			$depth = $r['depth'];
-		else
+		} else {
 			$depth = -1; // Flat.
-
+		}
 		$output .= walk_category_tree( $categories, $depth, $r );
 	}
 
-	if ( $title_li && 'list' == $style )
+	if ( $r['title_li'] && 'list' == $r['style'] )
 		$output .= '</ul></li>';
 
-	$output = apply_filters( 'wp_list_categories', $output );
-
-	if ( $echo )
-		echo $output;
-	else
-		return $output;
+	/**
+	 * Filters the HTML output of a taxonomy list.
+	 *
+	 * @since 2.1.0
+	 *
+	 * @param string $output HTML output.
+	 * @param array  $args   An array of taxonomy-listing arguments.
+	 */
+	$html = apply_filters( 'wp_list_categories', $output, $args );
+
+	if ( $r['echo'] ) {
+		echo $html;
+	} else {
+		return $html;
+	}
 }
 
 /**
@@ -506,38 +699,44 @@ function wp_list_categories( $args = '' ) {
  * The 'number' argument is how many tags to return. By default, the limit will
  * be to return the top 45 tags in the tag cloud list.
  *
- * The 'topic_count_text_callback' argument is a function, which, given the count
- * of the posts  with that tag, returns a text for the tooltip of the tag link.
+ * The 'topic_count_text' argument is a nooped plural from _n_noop() to generate the
+ * text for the tooltip of the tag link.
+ *
+ * The 'topic_count_text_callback' argument is a function, which given the count
+ * of the posts with that tag returns a text for the tooltip of the tag link.
+ *
+ * The 'post_type' argument is used only when 'link' is set to 'edit'. It determines the post_type
+ * passed to edit.php for the popular tags edit links.
  *
- * The 'exclude' and 'include' arguments are used for the {@link get_tags()}
- * function. Only one should be used, because only one will be used and the
- * other ignored, if they are both set.
+ * The 'exclude' and 'include' arguments are used for the get_tags() function. Only one
+ * should be used, because only one will be used and the other ignored, if they are both set.
  *
  * @since 2.3.0
  *
- * @param array|string $args Optional. Override default arguments.
- * @return array Generated tag cloud, only if no failures and 'array' is set for the 'format' argument.
+ * @param array|string|null $args Optional. Override default arguments.
+ * @return void|array Generated tag cloud, only if no failures and 'array' is set for the 'format' argument.
+ *                    Otherwise, this function outputs the tag cloud.
  */
 function wp_tag_cloud( $args = '' ) {
 	$defaults = array(
 		'smallest' => 8, 'largest' => 22, 'unit' => 'pt', 'number' => 45,
-		'format' => 'flat', 'orderby' => 'name', 'order' => 'ASC',
-		'exclude' => '', 'include' => '', 'link' => 'view', 'taxonomy' => 'post_tag', 'echo' => true
+		'format' => 'flat', 'separator' => "\n", 'orderby' => 'name', 'order' => 'ASC',
+		'exclude' => '', 'include' => '', 'link' => 'view', 'taxonomy' => 'post_tag', 'post_type' => '', 'echo' => true
 	);
 	$args = wp_parse_args( $args, $defaults );
 
 	$tags = get_terms( $args['taxonomy'], array_merge( $args, array( 'orderby' => 'count', 'order' => 'DESC' ) ) ); // Always query top tags
 
-	if ( empty( $tags ) )
+	if ( empty( $tags ) || is_wp_error( $tags ) )
 		return;
 
 	foreach ( $tags as $key => $tag ) {
 		if ( 'edit' == $args['link'] )
-			$link = get_edit_tag_link( $tag->term_id, $args['taxonomy'] );
+			$link = get_edit_term_link( $tag->term_id, $tag->taxonomy, $args['post_type'] );
 		else
-			$link = get_term_link( intval($tag->term_id), $args['taxonomy'] );
+			$link = get_term_link( intval($tag->term_id), $tag->taxonomy );
 		if ( is_wp_error( $link ) )
-			return false;
+			return;
 
 		$tags[ $key ]->link = $link;
 		$tags[ $key ]->id = $tag->term_id;
@@ -545,6 +744,14 @@ function wp_tag_cloud( $args = '' ) {
 
 	$return = wp_generate_tag_cloud( $tags, $args ); // Here's where those top tags get sorted according to $args
 
+	/**
+	 * Filters the tag cloud output.
+	 *
+	 * @since 2.3.0
+	 *
+	 * @param string $return HTML output of the tag cloud.
+	 * @param array  $args   An array of tag cloud arguments.
+	 */
 	$return = apply_filters( 'wp_tag_cloud', $return, $args );
 
 	if ( 'array' == $args['format'] || empty($args['echo']) )
@@ -554,139 +761,259 @@ function wp_tag_cloud( $args = '' ) {
 }
 
 /**
- * Default text for tooltip for tag links
+ * Default topic count scaling for tag links
  *
- * @param integer $count number of posts with that tag
- * @return string text for the tooltip of a tag link.
+ * @param int $count number of posts with that tag
+ * @return int scaled count
  */
-function default_topic_count_text( $count ) {
-	return sprintf( _n('%s topic', '%s topics', $count), number_format_i18n( $count ) );
+function default_topic_count_scale( $count ) {
+	return round(log10($count + 1) * 100);
 }
 
 /**
  * Generates a tag cloud (heatmap) from provided data.
  *
- * The text size is set by the 'smallest' and 'largest' arguments, which will
- * use the 'unit' argument value for the CSS text size unit. The 'format'
- * argument can be 'flat' (default), 'list', or 'array'. The flat value for the
- * 'format' argument will separate tags with spaces. The list value for the
- * 'format' argument will format the tags in a UL HTML list. The array value for
- * the 'format' argument will return in PHP array type format.
- *
- * The 'tag_cloud_sort' filter allows you to override the sorting done
- * by the 'orderby' argument; passed to the filter: $tags array and $args array.
- *
- * The 'orderby' argument will accept 'name' or 'count' and defaults to 'name'.
- * The 'order' is the direction to sort, defaults to 'ASC' and can be 'DESC' or
- * 'RAND'.
- *
- * The 'number' argument is how many tags to return. By default, the limit will
- * be to return the entire tag cloud list.
- *
- * The 'topic_count_text_callback' argument is a function, which given the count
- * of the posts  with that tag returns a text for the tooltip of the tag link.
- *
  * @todo Complete functionality.
  * @since 2.3.0
  *
  * @param array $tags List of tags.
- * @param string|array $args Optional, override default arguments.
- * @return string
+ * @param string|array $args {
+ *     Optional. Array of string of arguments for generating a tag cloud.
+ *
+ *     @type int      $smallest                   Smallest font size used to display tags. Paired
+ *                                                with the value of `$unit`, to determine CSS text
+ *                                                size unit. Default 8 (pt).
+ *     @type int      $largest                    Largest font size used to display tags. Paired
+ *                                                with the value of `$unit`, to determine CSS text
+ *                                                size unit. Default 22 (pt).
+ *     @type string   $unit                       CSS text size unit to use with the `$smallest`
+ *                                                and `$largest` values. Accepts any valid CSS text
+ *                                                size unit. Default 'pt'.
+ *     @type int      $number                     The number of tags to return. Accepts any
+ *                                                positive integer or zero to return all.
+ *                                                Default 0.
+ *     @type string   $format                     Format to display the tag cloud in. Accepts 'flat'
+ *                                                (tags separated with spaces), 'list' (tags displayed
+ *                                                in an unordered list), or 'array' (returns an array).
+ *                                                Default 'flat'.
+ *     @type string   $separator                  HTML or text to separate the tags. Default "\n" (newline).
+ *     @type string   $orderby                    Value to order tags by. Accepts 'name' or 'count'.
+ *                                                Default 'name'. The {@see 'tag_cloud_sort'} filter
+ *                                                can also affect how tags are sorted.
+ *     @type string   $order                      How to order the tags. Accepts 'ASC' (ascending),
+ *                                                'DESC' (descending), or 'RAND' (random). Default 'ASC'.
+ *     @type int|bool $filter                     Whether to enable filtering of the final output
+ *                                                via {@see 'wp_generate_tag_cloud'}. Default 1|true.
+ *     @type string   $topic_count_text           Nooped plural text from _n_noop() to supply to
+ *                                                tag tooltips. Default null.
+ *     @type callable $topic_count_text_callback  Callback used to generate nooped plural text for
+ *                                                tag tooltips based on the count. Default null.
+ *     @type callable $topic_count_scale_callback Callback used to determine the tag count scaling
+ *                                                value. Default default_topic_count_scale().
+ * }
+ * @return string|array Tag cloud as a string or an array, depending on 'format' argument.
  */
 function wp_generate_tag_cloud( $tags, $args = '' ) {
-	global $wp_rewrite;
 	$defaults = array(
 		'smallest' => 8, 'largest' => 22, 'unit' => 'pt', 'number' => 0,
-		'format' => 'flat', 'orderby' => 'name', 'order' => 'ASC',
-		'topic_count_text_callback' => 'default_topic_count_text',
-		'filter' => 1,
+		'format' => 'flat', 'separator' => "\n", 'orderby' => 'name', 'order' => 'ASC',
+		'topic_count_text' => null, 'topic_count_text_callback' => null,
+		'topic_count_scale_callback' => 'default_topic_count_scale', 'filter' => 1,
 	);
 
-	if ( !isset( $args['topic_count_text_callback'] ) && isset( $args['single_text'] ) && isset( $args['multiple_text'] ) ) {
-		$body = 'return sprintf (
-			_n('.var_export($args['single_text'], true).', '.var_export($args['multiple_text'], true).', $count),
-			number_format_i18n( $count ));';
-		$args['topic_count_text_callback'] = create_function('$count', $body);
-	}
-
 	$args = wp_parse_args( $args, $defaults );
 
-	extract( $args );
+	$return = ( 'array' === $args['format'] ) ? array() : '';
 
-	if ( empty( $tags ) )
-		return;
+	if ( empty( $tags ) ) {
+		return $return;
+	}
 
-	// SQL cannot save you; this is a second (potentially different) sort on a subset of data.
-	if ( 'name' == $orderby )
-		uasort( $tags, create_function('$a, $b', 'return strnatcasecmp($a->name, $b->name);') );
-	else
-		uasort( $tags, create_function('$a, $b', 'return ($a->count > $b->count);') );
+	// Juggle topic count tooltips:
+	if ( isset( $args['topic_count_text'] ) ) {
+		// First look for nooped plural support via topic_count_text.
+		$translate_nooped_plural = $args['topic_count_text'];
+	} elseif ( ! empty( $args['topic_count_text_callback'] ) ) {
+		// Look for the alternative callback style. Ignore the previous default.
+		if ( $args['topic_count_text_callback'] === 'default_topic_count_text' ) {
+			$translate_nooped_plural = _n_noop( '%s topic', '%s topics' );
+		} else {
+			$translate_nooped_plural = false;
+		}
+	} elseif ( isset( $args['single_text'] ) && isset( $args['multiple_text'] ) ) {
+		// If no callback exists, look for the old-style single_text and multiple_text arguments.
+		$translate_nooped_plural = _n_noop( $args['single_text'], $args['multiple_text'] );
+	} else {
+		// This is the default for when no callback, plural, or argument is passed in.
+		$translate_nooped_plural = _n_noop( '%s topic', '%s topics' );
+	}
 
-        $tags = apply_filters( 'tag_cloud_sort', $tags, $args );
+	/**
+	 * Filters how the items in a tag cloud are sorted.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param array $tags Ordered array of terms.
+	 * @param array $args An array of tag cloud arguments.
+	 */
+	$tags_sorted = apply_filters( 'tag_cloud_sort', $tags, $args );
+	if ( empty( $tags_sorted ) ) {
+		return $return;
+	}
 
-	if ( 'DESC' == $order )
-		$tags = array_reverse( $tags, true );
-	elseif ( 'RAND' == $order ) {
-		$keys = (array) array_rand( $tags, count( $tags ) );
-		$temp = array();
-		foreach ( $keys as $key )
-			$temp[$key] = $tags[$key];
+	if ( $tags_sorted !== $tags ) {
+		$tags = $tags_sorted;
+		unset( $tags_sorted );
+	} else {
+		if ( 'RAND' === $args['order'] ) {
+			shuffle( $tags );
+		} else {
+			// SQL cannot save you; this is a second (potentially different) sort on a subset of data.
+			if ( 'name' === $args['orderby'] ) {
+				uasort( $tags, '_wp_object_name_sort_cb' );
+			} else {
+				uasort( $tags, '_wp_object_count_sort_cb' );
+			}
 
-		$tags = $temp;
-		$temp = null;
-		unset( $temp );
+			if ( 'DESC' === $args['order'] ) {
+				$tags = array_reverse( $tags, true );
+			}
+		}
 	}
 
-	if ( $number > 0 )
-		$tags = array_slice($tags, 0, $number);
+	if ( $args['number'] > 0 )
+		$tags = array_slice( $tags, 0, $args['number'] );
 
 	$counts = array();
-	foreach ( (array) $tags as $key => $tag )
-		$counts[ $key ] = $tag->count;
+	$real_counts = array(); // For the alt tag
+	foreach ( (array) $tags as $key => $tag ) {
+		$real_counts[ $key ] = $tag->count;
+		$counts[ $key ] = call_user_func( $args['topic_count_scale_callback'], $tag->count );
+	}
 
 	$min_count = min( $counts );
 	$spread = max( $counts ) - $min_count;
 	if ( $spread <= 0 )
 		$spread = 1;
-	$font_spread = $largest - $smallest;
+	$font_spread = $args['largest'] - $args['smallest'];
 	if ( $font_spread < 0 )
 		$font_spread = 1;
 	$font_step = $font_spread / $spread;
 
+	// Assemble the data that will be used to generate the tag cloud markup.
+	$tags_data = array();
+	foreach ( $tags as $key => $tag ) {
+		$tag_id = isset( $tag->id ) ? $tag->id : $key;
+
+		$count = $counts[ $key ];
+		$real_count = $real_counts[ $key ];
+
+		if ( $translate_nooped_plural ) {
+			$title = sprintf( translate_nooped_plural( $translate_nooped_plural, $real_count ), number_format_i18n( $real_count ) );
+		} else {
+			$title = call_user_func( $args['topic_count_text_callback'], $real_count, $tag, $args );
+		}
+
+		$tags_data[] = array(
+			'id'         => $tag_id,
+			'url'        => '#' != $tag->link ? $tag->link : '#',
+			'name'	     => $tag->name,
+			'title'      => $title,
+			'slug'       => $tag->slug,
+			'real_count' => $real_count,
+			'class'	     => 'tag-link-' . $tag_id,
+			'font_size'  => $args['smallest'] + ( $count - $min_count ) * $font_step,
+		);
+	}
+
+	/**
+	 * Filters the data used to generate the tag cloud.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param array $tags_data An array of term data for term used to generate the tag cloud.
+	 */
+	$tags_data = apply_filters( 'wp_generate_tag_cloud_data', $tags_data );
+
 	$a = array();
 
-	$rel = ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) ? ' rel="tag"' : '';
+	// generate the output links array
+	foreach ( $tags_data as $key => $tag_data ) {
+		$class = $tag_data['class'] . ' tag-link-position-' . ( $key + 1 );
+		$a[] = "<a href='" . esc_url( $tag_data['url'] ) . "' class='" . esc_attr( $class ) . "' title='" . esc_attr( $tag_data['title'] ) . "' style='font-size: " . esc_attr( str_replace( ',', '.', $tag_data['font_size'] ) . $args['unit'] ) . ";'>" . esc_html( $tag_data['name'] ) . "</a>";
+	}
 
-	foreach ( $tags as $key => $tag ) {
-		$count = $counts[ $key ];
-		$tag_link = '#' != $tag->link ? esc_url( $tag->link ) : '#';
-		$tag_id = isset($tags[ $key ]->id) ? $tags[ $key ]->id : $key;
-		$tag_name = $tags[ $key ]->name;
-		$a[] = "<a href='$tag_link' class='tag-link-$tag_id' title='" . esc_attr( $topic_count_text_callback( $count ) ) . "'$rel style='font-size: " .
-			( $smallest + ( ( $count - $min_count ) * $font_step ) )
-			. "$unit;'>$tag_name</a>";
-	}
-
-	switch ( $format ) :
-	case 'array' :
-		$return =& $a;
-		break;
-	case 'list' :
-		$return = "<ul class='wp-tag-cloud'>\n\t<li>";
-		$return .= join( "</li>\n\t<li>", $a );
-		$return .= "</li>\n</ul>\n";
-		break;
-	default :
-		$return = join( "\n", $a );
-		break;
-	endswitch;
-
-    if ( $filter )
+	switch ( $args['format'] ) {
+		case 'array' :
+			$return =& $a;
+			break;
+		case 'list' :
+			$return = "<ul class='wp-tag-cloud'>\n\t<li>";
+			$return .= join( "</li>\n\t<li>", $a );
+			$return .= "</li>\n</ul>\n";
+			break;
+		default :
+			$return = join( $args['separator'], $a );
+			break;
+	}
+
+	if ( $args['filter'] ) {
+		/**
+		 * Filters the generated output of a tag cloud.
+		 *
+		 * The filter is only evaluated if a true value is passed
+		 * to the $filter argument in wp_generate_tag_cloud().
+		 *
+		 * @since 2.3.0
+		 *
+		 * @see wp_generate_tag_cloud()
+		 *
+		 * @param array|string $return String containing the generated HTML tag cloud output
+		 *                             or an array of tag links if the 'format' argument
+		 *                             equals 'array'.
+		 * @param array        $tags   An array of terms used in the tag cloud.
+		 * @param array        $args   An array of wp_generate_tag_cloud() arguments.
+		 */
 		return apply_filters( 'wp_generate_tag_cloud', $return, $tags, $args );
-    else
+	}
+
+	else
 		return $return;
 }
 
+/**
+ * Serves as a callback for comparing objects based on name.
+ *
+ * Used with `uasort()`.
+ *
+ * @since 3.1.0
+ * @access private
+ *
+ * @param object $a The first object to compare.
+ * @param object $b The second object to compare.
+ * @return int Negative number if `$a->name` is less than `$b->name`, zero if they are equal,
+ *             or greater than zero if `$a->name` is greater than `$b->name`.
+ */
+function _wp_object_name_sort_cb( $a, $b ) {
+	return strnatcasecmp( $a->name, $b->name );
+}
+
+/**
+ * Serves as a callback for comparing objects based on count.
+ *
+ * Used with `uasort()`.
+ *
+ * @since 3.1.0
+ * @access private
+ *
+ * @param object $a The first object to compare.
+ * @param object $b The second object to compare.
+ * @return bool Whether the count value for `$a` is greater than the count value for `$b`.
+ */
+function _wp_object_count_sort_cb( $a, $b ) {
+	return ( $a->count > $b->count );
+}
+
 //
 // Helper functions
 //
@@ -697,16 +1024,17 @@ function wp_generate_tag_cloud( $tags, $args = '' ) {
  * @uses Walker_Category to create HTML list content.
  * @since 2.1.0
  * @see Walker_Category::walk() for parameters and return description.
+ * @return string
  */
 function walk_category_tree() {
 	$args = func_get_args();
 	// the user's options are the third parameter
-	if ( empty($args[2]['walker']) || !is_a($args[2]['walker'], 'Walker') )
+	if ( empty( $args[2]['walker'] ) || ! ( $args[2]['walker'] instanceof Walker ) ) {
 		$walker = new Walker_Category;
-	else
+	} else {
 		$walker = $args[2]['walker'];
-
-	return call_user_func_array(array( &$walker, 'walk' ), $args );
+	}
+	return call_user_func_array( array( $walker, 'walk' ), $args );
 }
 
 /**
@@ -715,16 +1043,17 @@ function walk_category_tree() {
  * @uses Walker_CategoryDropdown to create HTML dropdown content.
  * @since 2.1.0
  * @see Walker_CategoryDropdown::walk() for parameters and return description.
+ * @return string
  */
 function walk_category_dropdown_tree() {
 	$args = func_get_args();
 	// the user's options are the third parameter
-	if ( empty($args[2]['walker']) || !is_a($args[2]['walker'], 'Walker') )
+	if ( empty( $args[2]['walker'] ) || ! ( $args[2]['walker'] instanceof Walker ) ) {
 		$walker = new Walker_CategoryDropdown;
-	else
+	} else {
 		$walker = $args[2]['walker'];
-
-	return call_user_func_array(array( &$walker, 'walk' ), $args );
+	}
+	return call_user_func_array( array( $walker, 'walk' ), $args );
 }
 
 //
@@ -735,40 +1064,42 @@ function walk_category_dropdown_tree() {
  * Retrieve the link to the tag.
  *
  * @since 2.3.0
- * @uses apply_filters() Calls 'tag_link' with tag link and tag ID as parameters.
+ * @see get_term_link()
  *
- * @param int $tag_id Tag (term) ID.
- * @return string
+ * @param int|object $tag Tag ID or object.
+ * @return string Link on success, empty string if tag does not exist.
  */
-function get_tag_link( $tag_id ) {
-	global $wp_rewrite;
-	$taglink = $wp_rewrite->get_tag_permastruct();
+function get_tag_link( $tag ) {
+	if ( ! is_object( $tag ) )
+		$tag = (int) $tag;
+
+	$tag = get_term_link( $tag, 'post_tag' );
 
-	$tag = &get_term( $tag_id, 'post_tag' );
 	if ( is_wp_error( $tag ) )
-		return $tag;
-	$slug = $tag->slug;
+		return '';
 
-	if ( empty( $taglink ) ) {
-		$file = get_option( 'home' ) . '/';
-		$taglink = $file . '?tag=' . $slug;
-	} else {
-		$taglink = str_replace( '%tag%', $slug, $taglink );
-		$taglink = get_option( 'home' ) . user_trailingslashit( $taglink, 'category' );
-	}
-	return apply_filters( 'tag_link', $taglink, $tag_id );
+	return $tag;
 }
 
 /**
  * Retrieve the tags for a post.
  *
  * @since 2.3.0
- * @uses apply_filters() Calls 'get_the_tags' filter on the list of post tags.
  *
  * @param int $id Post ID.
- * @return array
+ * @return array|false|WP_Error Array of tag objects on success, false on failure.
  */
 function get_the_tags( $id = 0 ) {
+
+	/**
+	 * Filters the array of tags for the given post.
+	 *
+	 * @since 2.3.0
+	 *
+	 * @see get_the_terms()
+	 *
+	 * @param array $terms An array of tags for the given post.
+	 */
 	return apply_filters( 'get_the_tags', get_the_terms( $id, 'post_tag' ) );
 }
 
@@ -776,15 +1107,27 @@ function get_the_tags( $id = 0 ) {
  * Retrieve the tags for a post formatted as a string.
  *
  * @since 2.3.0
- * @uses apply_filters() Calls 'the_tags' filter on string list of tags.
  *
  * @param string $before Optional. Before tags.
  * @param string $sep Optional. Between tags.
  * @param string $after Optional. After tags.
- * @return string
+ * @param int $id Optional. Post ID. Defaults to the current post.
+ * @return string|false|WP_Error A list of tags on success, false if there are no terms, WP_Error on failure.
  */
-function get_the_tag_list( $before = '', $sep = '', $after = '' ) {
-	return apply_filters( 'the_tags', get_the_term_list( 0, 'post_tag', $before, $sep, $after ), $before, $sep, $after);
+function get_the_tag_list( $before = '', $sep = '', $after = '', $id = 0 ) {
+
+	/**
+	 * Filters the tags list for a given post.
+	 *
+	 * @since 2.3.0
+	 *
+	 * @param string $tag_list List of tags.
+	 * @param string $before   String to use before tags.
+	 * @param string $sep      String to use between the tags.
+	 * @param string $after    String to use after tags.
+	 * @param int    $id       Post ID.
+	 */
+	return apply_filters( 'the_tags', get_the_term_list( $id, 'post_tag', $before, $sep, $after ), $before, $sep, $after, $id );
 }
 
 /**
@@ -795,7 +1138,6 @@ function get_the_tag_list( $before = '', $sep = '', $after = '' ) {
  * @param string $before Optional. Before list.
  * @param string $sep Optional. Separate items using this.
  * @param string $after Optional. After list.
- * @return string
  */
 function the_tags( $before = null, $sep = ', ', $after = '' ) {
 	if ( null === $before )
@@ -806,7 +1148,7 @@ function the_tags( $before = null, $sep = ', ', $after = '' ) {
 /**
  * Retrieve tag description.
  *
- * @since 2.8
+ * @since 2.8.0
  *
  * @param int $tag Optional. Tag ID. Will use global tag ID by default.
  * @return string Tag description, available.
@@ -818,46 +1160,57 @@ function tag_description( $tag = 0 ) {
 /**
  * Retrieve term description.
  *
- * @since 2.8
+ * @since 2.8.0
  *
  * @param int $term Optional. Term ID. Will use global term ID by default.
+ * @param string $taxonomy Optional taxonomy name. Defaults to 'post_tag'.
  * @return string Term description, available.
  */
 function term_description( $term = 0, $taxonomy = 'post_tag' ) {
-	if ( !$term && ( is_tax() || is_tag() || is_category() ) ) {
-		global $wp_query;
-		$term = $wp_query->get_queried_object();
-		$taxonomy = $term->taxonomy;
-		$term = $term->term_id;
+	if ( ! $term && ( is_tax() || is_tag() || is_category() ) ) {
+		$term = get_queried_object();
+		if ( $term ) {
+			$taxonomy = $term->taxonomy;
+			$term = $term->term_id;
+		}
 	}
-	return get_term_field( 'description', $term, $taxonomy );
+	$description = get_term_field( 'description', $term, $taxonomy );
+	return is_wp_error( $description ) ? '' : $description;
 }
 
 /**
  * Retrieve the terms of the taxonomy that are attached to the post.
  *
- * This function can only be used within the loop.
- *
  * @since 2.5.0
  *
- * @param int $id Post ID. Is not optional.
+ * @param int|object $post Post ID or object.
  * @param string $taxonomy Taxonomy name.
- * @return array|bool False on failure. Array of term objects on success.
+ * @return array|false|WP_Error Array of WP_Term objects on success, false if there are no terms
+ *                              or the post does not exist, WP_Error on failure.
  */
-function get_the_terms( $id = 0, $taxonomy ) {
-	global $post;
-
- 	$id = (int) $id;
-
-	if ( ! $id && ! in_the_loop() )
-		return false; // in-the-loop function
+function get_the_terms( $post, $taxonomy ) {
+	if ( ! $post = get_post( $post ) )
+		return false;
 
-	if ( !$id )
-		$id = (int) $post->ID;
+	$terms = get_object_term_cache( $post->ID, $taxonomy );
+	if ( false === $terms ) {
+		$terms = wp_get_object_terms( $post->ID, $taxonomy );
+		if ( ! is_wp_error( $terms ) ) {
+			$term_ids = wp_list_pluck( $terms, 'term_id' );
+			wp_cache_add( $post->ID, $term_ids, $taxonomy . '_relationships' );
+		}
+	}
 
-	$terms = get_object_term_cache( $id, $taxonomy );
-	if ( false === $terms )
-		$terms = wp_get_object_terms( $id, $taxonomy );
+	/**
+	 * Filters the list of terms attached to the given post.
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param array|WP_Error $terms    List of attached terms, or WP_Error on failure.
+	 * @param int            $post_id  Post ID.
+	 * @param string         $taxonomy Name of the taxonomy.
+	 */
+	$terms = apply_filters( 'get_the_terms', $terms, $post->ID, $taxonomy );
 
 	if ( empty( $terms ) )
 		return false;
@@ -866,18 +1219,18 @@ function get_the_terms( $id = 0, $taxonomy ) {
 }
 
 /**
- * Retrieve terms as a list with specified format.
+ * Retrieve a post's terms as a list with specified format.
  *
  * @since 2.5.0
  *
- * @param int $id Term ID.
+ * @param int $id Post ID.
  * @param string $taxonomy Taxonomy name.
  * @param string $before Optional. Before list.
  * @param string $sep Optional. Separate items using this.
  * @param string $after Optional. After list.
- * @return string
+ * @return string|false|WP_Error A list of terms on success, false if there are no terms, WP_Error on failure.
  */
-function get_the_term_list( $id = 0, $taxonomy, $before = '', $sep = '', $after = '' ) {
+function get_the_term_list( $id, $taxonomy, $before = '', $sep = '', $after = '' ) {
 	$terms = get_the_terms( $id, $taxonomy );
 
 	if ( is_wp_error( $terms ) )
@@ -886,14 +1239,27 @@ function get_the_term_list( $id = 0, $taxonomy, $before = '', $sep = '', $after
 	if ( empty( $terms ) )
 		return false;
 
+	$links = array();
+
 	foreach ( $terms as $term ) {
 		$link = get_term_link( $term, $taxonomy );
-		if ( is_wp_error( $link ) )
+		if ( is_wp_error( $link ) ) {
 			return $link;
-		$term_links[] = '<a href="' . $link . '" rel="tag">' . $term->name . '</a>';
+		}
+		$links[] = '<a href="' . esc_url( $link ) . '" rel="tag">' . $term->name . '</a>';
 	}
 
-	$term_links = apply_filters( "term_links-$taxonomy", $term_links );
+	/**
+	 * Filters the term links for a given taxonomy.
+	 *
+	 * The dynamic portion of the filter name, `$taxonomy`, refers
+	 * to the taxonomy slug.
+	 *
+	 * @since 2.5.0
+	 *
+	 * @param array $links An array of term links.
+	 */
+	$term_links = apply_filters( "term_links-$taxonomy", $links );
 
 	return $before . join( $sep, $term_links ) . $after;
 }
@@ -903,19 +1269,44 @@ function get_the_term_list( $id = 0, $taxonomy, $before = '', $sep = '', $after
  *
  * @since 2.5.0
  *
- * @param int $id Term ID.
+ * @param int $id Post ID.
  * @param string $taxonomy Taxonomy name.
  * @param string $before Optional. Before list.
  * @param string $sep Optional. Separate items using this.
  * @param string $after Optional. After list.
- * @return null|bool False on WordPress error. Returns null when displaying.
+ * @return false|void False on WordPress error.
  */
-function the_terms( $id, $taxonomy, $before = '', $sep = '', $after = '' ) {
-	$return = get_the_term_list( $id, $taxonomy, $before, $sep, $after );
-	if ( is_wp_error( $return ) )
+function the_terms( $id, $taxonomy, $before = '', $sep = ', ', $after = '' ) {
+	$term_list = get_the_term_list( $id, $taxonomy, $before, $sep, $after );
+
+	if ( is_wp_error( $term_list ) )
 		return false;
-	else
-		echo $return;
+
+	/**
+	 * Filters the list of terms to display.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param array  $term_list List of terms to display.
+	 * @param string $taxonomy  The taxonomy name.
+	 * @param string $before    String to use before the terms.
+	 * @param string $sep       String to use between the terms.
+	 * @param string $after     String to use after the terms.
+	 */
+	echo apply_filters( 'the_terms', $term_list, $taxonomy, $before, $sep, $after );
+}
+
+/**
+ * Check if the current post has any of given category.
+ *
+ * @since 3.1.0
+ *
+ * @param string|int|array $category Optional. The category name/term_id/slug or array of them to check for.
+ * @param int|object $post Optional. Post to check instead of the current post.
+ * @return bool True if the current post has any of the given categories (or any category, if no category specified).
+ */
+function has_category( $category = '', $post = null ) {
+	return has_term( $category, 'category', $post );
 }
 
 /**
@@ -931,26 +1322,37 @@ function the_terms( $id, $taxonomy, $before = '', $sep = '', $after = '' ) {
  *
  * @since 2.6.0
  *
- * @uses is_object_in_term()
- *
  * @param string|int|array $tag Optional. The tag name/term_id/slug or array of them to check for.
- * @param int|post object Optional.  Post to check instead of the current post. @since 2.7.0
- * @return bool True if the current post has any of the the given tags (or any tag, if no tag specified).
+ * @param int|object $post Optional. Post to check instead of the current post. (since 2.7.0)
+ * @return bool True if the current post has any of the given tags (or any tag, if no tag specified).
  */
-function has_tag( $tag = '', $_post = null ) {
-	if ( $_post ) {
-		$_post = get_post( $_post );
-	} else {
-		$_post =& $GLOBALS['post'];
-	}
+function has_tag( $tag = '', $post = null ) {
+	return has_term( $tag, 'post_tag', $post );
+}
 
-	if ( !$_post )
+/**
+ * Check if the current post has any of given terms.
+ *
+ * The given terms are checked against the post's terms' term_ids, names and slugs.
+ * Terms given as integers will only be checked against the post's terms' term_ids.
+ * If no terms are given, determines if post has any terms.
+ *
+ * @since 3.1.0
+ *
+ * @param string|int|array $term Optional. The term name/term_id/slug or array of them to check for.
+ * @param string $taxonomy Taxonomy name
+ * @param int|object $post Optional. Post to check instead of the current post.
+ * @return bool True if the current post has any of the given tags (or any tag, if no tag specified).
+ */
+function has_term( $term = '', $taxonomy = '', $post = null ) {
+	$post = get_post($post);
+
+	if ( !$post )
 		return false;
 
-	$r = is_object_in_term( $_post->ID, 'post_tag', $tag );
+	$r = is_object_in_term( $post->ID, $taxonomy, $term );
 	if ( is_wp_error( $r ) )
 		return false;
+
 	return $r;
 }
-
-?>