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   1  <?php
   2  /**
   3   * Category Template Tags and API.
   4   *
   5   * @package WordPress
   6   * @subpackage Template
   7   */
   8  
   9  /**
  10   * Retrieve category children list separated before and after the term IDs.
  11   *
  12   * @since 1.2.0
  13   *
  14   * @param int $id Category ID to retrieve children.
  15   * @param string $before Optional. Prepend before category term ID.
  16   * @param string $after Optional, default is empty string. Append after category term ID.
  17   * @param array $visited Optional. Category Term IDs that have already been added.
  18   * @return string
  19   */
  20  function get_category_children( $id, $before = '/', $after = '', $visited = array() ) {
  21      if ( 0 == $id )
  22          return '';
  23  
  24      $chain = '';
  25      /** TODO: consult hierarchy */
  26      $cat_ids = get_all_category_ids();
  27      foreach ( (array) $cat_ids as $cat_id ) {
  28          if ( $cat_id == $id )
  29              continue;
  30  
  31          $category = get_category( $cat_id );
  32          if ( is_wp_error( $category ) )
  33              return $category;
  34          if ( $category->parent == $id && !in_array( $category->term_id, $visited ) ) {
  35              $visited[] = $category->term_id;
  36              $chain .= $before.$category->term_id.$after;
  37              $chain .= get_category_children( $category->term_id, $before, $after );
  38          }
  39      }
  40      return $chain;
  41  }
  42  
  43  /**
  44   * Retrieve category link URL.
  45   *
  46   * @since 1.0.0
  47   * @uses apply_filters() Calls 'category_link' filter on category link and category ID.
  48   *
  49   * @param int $category_id Category ID.
  50   * @return string
  51   */
  52  function get_category_link( $category_id ) {
  53      global $wp_rewrite;
  54      $catlink = $wp_rewrite->get_category_permastruct();
  55  
  56      if ( empty( $catlink ) ) {
  57          $file = get_option( 'home' ) . '/';
  58          $catlink = $file . '?cat=' . $category_id;
  59      } else {
  60          $category = &get_category( $category_id );
  61          if ( is_wp_error( $category ) )
  62              return $category;
  63          $category_nicename = $category->slug;
  64  
  65          if ( $category->parent == $category_id ) // recursive recursion
  66              $category->parent = 0;
  67          elseif ($category->parent != 0 )
  68              $category_nicename = get_category_parents( $category->parent, false, '/', true ) . $category_nicename;
  69  
  70          $catlink = str_replace( '%category%', $category_nicename, $catlink );
  71          $catlink = get_option( 'home' ) . user_trailingslashit( $catlink, 'category' );
  72      }
  73      return apply_filters( 'category_link', $catlink, $category_id );
  74  }
  75  
  76  /**
  77   * Retrieve category parents with separator.
  78   *
  79   * @since 1.2.0
  80   *
  81   * @param int $id Category ID.
  82   * @param bool $link Optional, default is false. Whether to format with link.
  83   * @param string $separator Optional, default is '/'. How to separate categories.
  84   * @param bool $nicename Optional, default is false. Whether to use nice name for display.
  85   * @param array $visited Optional. Already linked to categories to prevent duplicates.
  86   * @return string
  87   */
  88  function get_category_parents( $id, $link = false, $separator = '/', $nicename = false, $visited = array() ) {
  89      $chain = '';
  90      $parent = &get_category( $id );
  91      if ( is_wp_error( $parent ) )
  92          return $parent;
  93  
  94      if ( $nicename )
  95          $name = $parent->slug;
  96      else
  97          $name = $parent->cat_name;
  98  
  99      if ( $parent->parent && ( $parent->parent != $parent->term_id ) && !in_array( $parent->parent, $visited ) ) {
 100          $visited[] = $parent->parent;
 101          $chain .= get_category_parents( $parent->parent, $link, $separator, $nicename, $visited );
 102      }
 103  
 104      if ( $link )
 105          $chain .= '<a href="' . get_category_link( $parent->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $parent->cat_name ) . '">'.$name.'</a>' . $separator;
 106      else
 107          $chain .= $name.$separator;
 108      return $chain;
 109  }
 110  
 111  /**
 112   * Retrieve post categories.
 113   *
 114   * @since 0.71
 115   * @uses $post
 116   *
 117   * @param int $id Optional, default to current post ID. The post ID.
 118   * @return array
 119   */
 120  function get_the_category( $id = false ) {
 121      global $post;
 122  
 123      $id = (int) $id;
 124      if ( !$id )
 125          $id = (int) $post->ID;
 126  
 127      $categories = get_object_term_cache( $id, 'category' );
 128      if ( false === $categories ) {
 129          $categories = wp_get_object_terms( $id, 'category' );
 130          wp_cache_add($id, $categories, 'category_relationships');
 131      }
 132  
 133      if ( !empty( $categories ) )
 134          usort( $categories, '_usort_terms_by_name' );
 135      else
 136          $categories = array();
 137  
 138      foreach ( (array) array_keys( $categories ) as $key ) {
 139          _make_cat_compat( $categories[$key] );
 140      }
 141  
 142      return $categories;
 143  }
 144  
 145  /**
 146   * Sort categories by name.
 147   *
 148   * Used by usort() as a callback, should not be used directly. Can actually be
 149   * used to sort any term object.
 150   *
 151   * @since 2.3.0
 152   * @access private
 153   *
 154   * @param object $a
 155   * @param object $b
 156   * @return int
 157   */
 158  function _usort_terms_by_name( $a, $b ) {
 159      return strcmp( $a->name, $b->name );
 160  }
 161  
 162  /**
 163   * Sort categories by ID.
 164   *
 165   * Used by usort() as a callback, should not be used directly. Can actually be
 166   * used to sort any term object.
 167   *
 168   * @since 2.3.0
 169   * @access private
 170   *
 171   * @param object $a
 172   * @param object $b
 173   * @return int
 174   */
 175  function _usort_terms_by_ID( $a, $b ) {
 176      if ( $a->term_id > $b->term_id )
 177          return 1;
 178      elseif ( $a->term_id < $b->term_id )
 179          return -1;
 180      else
 181          return 0;
 182  }
 183  
 184  /**
 185   * Retrieve category name based on category ID.
 186   *
 187   * @since 0.71
 188   *
 189   * @param int $cat_ID Category ID.
 190   * @return string Category name.
 191   */
 192  function get_the_category_by_ID( $cat_ID ) {
 193      $cat_ID = (int) $cat_ID;
 194      $category = &get_category( $cat_ID );
 195      if ( is_wp_error( $category ) )
 196          return $category;
 197      return $category->name;
 198  }
 199  
 200  /**
 201   * Retrieve category list in either HTML list or custom format.
 202   *
 203   * @since 1.5.1
 204   *
 205   * @param string $separator Optional, default is empty string. Separator for between the categories.
 206   * @param string $parents Optional. How to display the parents.
 207   * @param int $post_id Optional. Post ID to retrieve categories.
 208   * @return string
 209   */
 210  function get_the_category_list( $separator = '', $parents='', $post_id = false ) {
 211      global $wp_rewrite;
 212      $categories = get_the_category( $post_id );
 213      if ( empty( $categories ) )
 214          return apply_filters( 'the_category', __( 'Uncategorized' ), $separator, $parents );
 215  
 216      $rel = ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) ? 'rel="category tag"' : 'rel="category"';
 217  
 218      $thelist = '';
 219      if ( '' == $separator ) {
 220          $thelist .= '<ul class="post-categories">';
 221          foreach ( $categories as $category ) {
 222              $thelist .= "\n\t<li>";
 223              switch ( strtolower( $parents ) ) {
 224                  case 'multiple':
 225                      if ( $category->parent )
 226                          $thelist .= get_category_parents( $category->parent, true, $separator );
 227                      $thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->name.'</a></li>';
 228                      break;
 229                  case 'single':
 230                      $thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>';
 231                      if ( $category->parent )
 232                          $thelist .= get_category_parents( $category->parent, false, $separator );
 233                      $thelist .= $category->name.'</a></li>';
 234                      break;
 235                  case '':
 236                  default:
 237                      $thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->cat_name.'</a></li>';
 238              }
 239          }
 240          $thelist .= '</ul>';
 241      } else {
 242          $i = 0;
 243          foreach ( $categories as $category ) {
 244              if ( 0 < $i )
 245                  $thelist .= $separator . ' ';
 246              switch ( strtolower( $parents ) ) {
 247                  case 'multiple':
 248                      if ( $category->parent )
 249                          $thelist .= get_category_parents( $category->parent, true, $separator );
 250                      $thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->cat_name.'</a>';
 251                      break;
 252                  case 'single':
 253                      $thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>';
 254                      if ( $category->parent )
 255                          $thelist .= get_category_parents( $category->parent, false, $separator );
 256                      $thelist .= "$category->cat_name</a>";
 257                      break;
 258                  case '':
 259                  default:
 260                      $thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . $rel . '>' . $category->name.'</a>';
 261              }
 262              ++$i;
 263          }
 264      }
 265      return apply_filters( 'the_category', $thelist, $separator, $parents );
 266  }
 267  
 268  
 269  /**
 270   * Check if the current post in within any of the given categories.
 271   *
 272   * The given categories are checked against the post's categories' term_ids, names and slugs.
 273   * Categories given as integers will only be checked against the post's categories' term_ids.
 274   *
 275   * Prior to v2.5 of WordPress, category names were not supported.
 276   * Prior to v2.7, category slugs were not supported.
 277   * Prior to v2.7, only one category could be compared: in_category( $single_category ).
 278   * Prior to v2.7, this function could only be used in the WordPress Loop.
 279   * As of 2.7, the function can be used anywhere if it is provided a post ID or post object.
 280   *
 281   * @since 1.2.0
 282   *
 283   * @uses is_object_in_term()
 284   *
 285   * @param int|string|array $category. Category ID, name or slug, or array of said.
 286   * @param int|post object Optional.  Post to check instead of the current post. @since 2.7.0
 287   * @return bool True if the current post is in any of the given categories.
 288   */
 289  function in_category( $category, $_post = null ) {
 290      if ( empty( $category ) )
 291          return false;
 292  
 293      if ( $_post ) {
 294          $_post = get_post( $_post );
 295      } else {
 296          $_post =& $GLOBALS['post'];
 297      }
 298  
 299      if ( !$_post )
 300          return false;
 301  
 302      $r = is_object_in_term( $_post->ID, 'category', $category );
 303      if ( is_wp_error( $r ) )
 304          return false;
 305      return $r;
 306  }
 307  
 308  /**
 309   * Display the category list for the post.
 310   *
 311   * @since 0.71
 312   *
 313   * @param string $separator Optional, default is empty string. Separator for between the categories.
 314   * @param string $parents Optional. How to display the parents.
 315   * @param int $post_id Optional. Post ID to retrieve categories.
 316   */
 317  function the_category( $separator = '', $parents='', $post_id = false ) {
 318      echo get_the_category_list( $separator, $parents, $post_id );
 319  }
 320  
 321  /**
 322   * Retrieve category description.
 323   *
 324   * @since 1.0.0
 325   *
 326   * @param int $category Optional. Category ID. Will use global category ID by default.
 327   * @return string Category description, available.
 328   */
 329  function category_description( $category = 0 ) {
 330      global $cat;
 331      if ( !$category )
 332          $category = $cat;
 333  
 334      return get_term_field( 'description', $category, 'category' );
 335  }
 336  
 337  /**
 338   * Display or retrieve the HTML dropdown list of categories.
 339   *
 340   * The list of arguments is below:
 341   *     'show_option_all' (string) - Text to display for showing all categories.
 342   *     'show_option_none' (string) - Text to display for showing no categories.
 343   *     'orderby' (string) default is 'ID' - What column to use for ordering the
 344   * categories.
 345   *     'order' (string) default is 'ASC' - What direction to order categories.
 346   *     'show_last_update' (bool|int) default is 0 - See {@link get_categories()}
 347   *     'show_count' (bool|int) default is 0 - Whether to show how many posts are
 348   * in the category.
 349   *     'hide_empty' (bool|int) default is 1 - Whether to hide categories that
 350   * don't have any posts attached to them.
 351   *     'child_of' (int) default is 0 - See {@link get_categories()}.
 352   *     'exclude' (string) - See {@link get_categories()}.
 353   *     'echo' (bool|int) default is 1 - Whether to display or retrieve content.
 354   *     'depth' (int) - The max depth.
 355   *     'tab_index' (int) - Tab index for select element.
 356   *     'name' (string) - The name attribute value for selected element.
 357   *     'class' (string) - The class attribute value for selected element.
 358   *     'selected' (int) - Which category ID is selected.
 359   *
 360   * The 'hierarchical' argument, which is disabled by default, will override the
 361   * depth argument, unless it is true. When the argument is false, it will
 362   * display all of the categories. When it is enabled it will use the value in
 363   * the 'depth' argument.
 364   *
 365   * @since 2.1.0
 366   *
 367   * @param string|array $args Optional. Override default arguments.
 368   * @return string HTML content only if 'echo' argument is 0.
 369   */
 370  function wp_dropdown_categories( $args = '' ) {
 371      $defaults = array(
 372          'show_option_all' => '', 'show_option_none' => '',
 373          'orderby' => 'ID', 'order' => 'ASC',
 374          'show_last_update' => 0, 'show_count' => 0,
 375          'hide_empty' => 1, 'child_of' => 0,
 376          'exclude' => '', 'echo' => 1,
 377          'selected' => 0, 'hierarchical' => 0,
 378          'name' => 'cat', 'class' => 'postform',
 379          'depth' => 0, 'tab_index' => 0
 380      );
 381  
 382      $defaults['selected'] = ( is_category() ) ? get_query_var( 'cat' ) : 0;
 383  
 384      $r = wp_parse_args( $args, $defaults );
 385      $r['include_last_update_time'] = $r['show_last_update'];
 386      extract( $r );
 387  
 388      $tab_index_attribute = '';
 389      if ( (int) $tab_index > 0 )
 390          $tab_index_attribute = " tabindex=\"$tab_index\"";
 391  
 392      $categories = get_categories( $r );
 393  
 394      $output = '';
 395      if ( ! empty( $categories ) ) {
 396          $output = "<select name='$name' id='$name' class='$class' $tab_index_attribute>\n";
 397  
 398          if ( $show_option_all ) {
 399              $show_option_all = apply_filters( 'list_cats', $show_option_all );
 400              $selected = ( '0' === strval($r['selected']) ) ? " selected='selected'" : '';
 401              $output .= "\t<option value='0'$selected>$show_option_all</option>\n";
 402          }
 403  
 404          if ( $show_option_none ) {
 405              $show_option_none = apply_filters( 'list_cats', $show_option_none );
 406              $selected = ( '-1' === strval($r['selected']) ) ? " selected='selected'" : '';
 407              $output .= "\t<option value='-1'$selected>$show_option_none</option>\n";
 408          }
 409  
 410          if ( $hierarchical )
 411              $depth = $r['depth'];  // Walk the full depth.
 412          else
 413              $depth = -1; // Flat.
 414  
 415          $output .= walk_category_dropdown_tree( $categories, $depth, $r );
 416          $output .= "</select>\n";
 417      }
 418  
 419      $output = apply_filters( 'wp_dropdown_cats', $output );
 420  
 421      if ( $echo )
 422          echo $output;
 423  
 424      return $output;
 425  }
 426  
 427  /**
 428   * Display or retrieve the HTML list of categories.
 429   *
 430   * The list of arguments is below:
 431   *     'show_option_all' (string) - Text to display for showing all categories.
 432   *     'orderby' (string) default is 'ID' - What column to use for ordering the
 433   * categories.
 434   *     'order' (string) default is 'ASC' - What direction to order categories.
 435   *     'show_last_update' (bool|int) default is 0 - See {@link
 436   * walk_category_dropdown_tree()}
 437   *     'show_count' (bool|int) default is 0 - Whether to show how many posts are
 438   * in the category.
 439   *     'hide_empty' (bool|int) default is 1 - Whether to hide categories that
 440   * don't have any posts attached to them.
 441   *     'use_desc_for_title' (bool|int) default is 1 - Whether to use the
 442   * description instead of the category title.
 443   *     'feed' - See {@link get_categories()}.
 444   *     'feed_type' - See {@link get_categories()}.
 445   *     'feed_image' - See {@link get_categories()}.
 446   *     'child_of' (int) default is 0 - See {@link get_categories()}.
 447   *     'exclude' (string) - See {@link get_categories()}.
 448   *     'exclude_tree' (string) - See {@link get_categories()}.
 449   *     'echo' (bool|int) default is 1 - Whether to display or retrieve content.
 450   *     'current_category' (int) - See {@link get_categories()}.
 451   *     'hierarchical' (bool) - See {@link get_categories()}.
 452   *     'title_li' (string) - See {@link get_categories()}.
 453   *     'depth' (int) - The max depth.
 454   *
 455   * @since 2.1.0
 456   *
 457   * @param string|array $args Optional. Override default arguments.
 458   * @return string HTML content only if 'echo' argument is 0.
 459   */
 460  function wp_list_categories( $args = '' ) {
 461      $defaults = array(
 462          'show_option_all' => '', 'orderby' => 'name',
 463          'order' => 'ASC', 'show_last_update' => 0,
 464          'style' => 'list', 'show_count' => 0,
 465          'hide_empty' => 1, 'use_desc_for_title' => 1,
 466          'child_of' => 0, 'feed' => '', 'feed_type' => '',
 467          'feed_image' => '', 'exclude' => '', 'exclude_tree' => '', 'current_category' => 0,
 468          'hierarchical' => true, 'title_li' => __( 'Categories' ),
 469          'echo' => 1, 'depth' => 0
 470      );
 471  
 472      $r = wp_parse_args( $args, $defaults );
 473  
 474      if ( !isset( $r['pad_counts'] ) && $r['show_count'] && $r['hierarchical'] ) {
 475          $r['pad_counts'] = true;
 476      }
 477  
 478      if ( isset( $r['show_date'] ) ) {
 479          $r['include_last_update_time'] = $r['show_date'];
 480      }
 481  
 482      if ( true == $r['hierarchical'] ) {
 483          $r['exclude_tree'] = $r['exclude'];
 484          $r['exclude'] = '';
 485      }
 486  
 487      extract( $r );
 488  
 489      $categories = get_categories( $r );
 490  
 491      $output = '';
 492      if ( $title_li && 'list' == $style )
 493              $output = '<li class="categories">' . $r['title_li'] . '<ul>';
 494  
 495      if ( empty( $categories ) ) {
 496          if ( 'list' == $style )
 497              $output .= '<li>' . __( "No categories" ) . '</li>';
 498          else
 499              $output .= __( "No categories" );
 500      } else {
 501          global $wp_query;
 502  
 503          if( !empty( $show_option_all ) )
 504              if ( 'list' == $style )
 505                  $output .= '<li><a href="' .  get_bloginfo( 'url' )  . '">' . $show_option_all . '</a></li>';
 506              else
 507                  $output .= '<a href="' .  get_bloginfo( 'url' )  . '">' . $show_option_all . '</a>';
 508  
 509          if ( empty( $r['current_category'] ) && is_category() )
 510              $r['current_category'] = $wp_query->get_queried_object_id();
 511  
 512          if ( $hierarchical )
 513              $depth = $r['depth'];
 514          else
 515              $depth = -1; // Flat.
 516  
 517          $output .= walk_category_tree( $categories, $depth, $r );
 518      }
 519  
 520      if ( $title_li && 'list' == $style )
 521          $output .= '</ul></li>';
 522  
 523      $output = apply_filters( 'wp_list_categories', $output );
 524  
 525      if ( $echo )
 526          echo $output;
 527      else
 528          return $output;
 529  }
 530  
 531  /**
 532   * Display tag cloud.
 533   *
 534   * The text size is set by the 'smallest' and 'largest' arguments, which will
 535   * use the 'unit' argument value for the CSS text size unit. The 'format'
 536   * argument can be 'flat' (default), 'list', or 'array'. The flat value for the
 537   * 'format' argument will separate tags with spaces. The list value for the
 538   * 'format' argument will format the tags in a UL HTML list. The array value for
 539   * the 'format' argument will return in PHP array type format.
 540   *
 541   * The 'orderby' argument will accept 'name' or 'count' and defaults to 'name'.
 542   * The 'order' is the direction to sort, defaults to 'ASC' and can be 'DESC'.
 543   *
 544   * The 'number' argument is how many tags to return. By default, the limit will
 545   * be to return the top 45 tags in the tag cloud list.
 546   *
 547   * The 'topic_count_text_callback' argument is a function, which, given the count
 548   * of the posts  with that tag, returns a text for the tooltip of the tag link.
 549   *
 550   * The 'exclude' and 'include' arguments are used for the {@link get_tags()}
 551   * function. Only one should be used, because only one will be used and the
 552   * other ignored, if they are both set.
 553   *
 554   * @since 2.3.0
 555   *
 556   * @param array|string $args Optional. Override default arguments.
 557   * @return array Generated tag cloud, only if no failures and 'array' is set for the 'format' argument.
 558   */
 559  function wp_tag_cloud( $args = '' ) {
 560      $defaults = array(
 561          'smallest' => 8, 'largest' => 22, 'unit' => 'pt', 'number' => 45,
 562          'format' => 'flat', 'orderby' => 'name', 'order' => 'ASC',
 563          'exclude' => '', 'include' => '', 'link' => 'view'
 564      );
 565      $args = wp_parse_args( $args, $defaults );
 566  
 567      $tags = get_tags( array_merge( $args, array( 'orderby' => 'count', 'order' => 'DESC' ) ) ); // Always query top tags
 568  
 569      if ( empty( $tags ) )
 570          return;
 571  
 572      foreach ( $tags as $key => $tag ) {
 573          if ( 'edit' == $args['link'] )
 574              $link = get_edit_tag_link( $tag->term_id );
 575          else
 576              $link = get_tag_link( $tag->term_id );
 577          if ( is_wp_error( $link ) )
 578              return false;
 579  
 580          $tags[ $key ]->link = $link;
 581          $tags[ $key ]->id = $tag->term_id;
 582      }
 583  
 584      $return = wp_generate_tag_cloud( $tags, $args ); // Here's where those top tags get sorted according to $args
 585  
 586      $return = apply_filters( 'wp_tag_cloud', $return, $args );
 587  
 588      if ( 'array' == $args['format'] )
 589          return $return;
 590  
 591      echo $return;
 592  }
 593  
 594  /**
 595   * Default text for tooltip for tag links
 596   *
 597   * @param integer $count number of posts with that tag
 598   * @return string text for the tooltip of a tag link.
 599   */
 600  function default_topic_count_text( $count ) {
 601      return sprintf( __ngettext('%s topic', '%s topics', $count), number_format_i18n( $count ) );
 602  }
 603  
 604  /**
 605   * Generates a tag cloud (heatmap) from provided data.
 606   *
 607   * The text size is set by the 'smallest' and 'largest' arguments, which will
 608   * use the 'unit' argument value for the CSS text size unit. The 'format'
 609   * argument can be 'flat' (default), 'list', or 'array'. The flat value for the
 610   * 'format' argument will separate tags with spaces. The list value for the
 611   * 'format' argument will format the tags in a UL HTML list. The array value for
 612   * the 'format' argument will return in PHP array type format.
 613   *
 614   * The 'orderby' argument will accept 'name' or 'count' and defaults to 'name'.
 615   * The 'order' is the direction to sort, defaults to 'ASC' and can be 'DESC' or
 616   * 'RAND'.
 617   *
 618   * The 'number' argument is how many tags to return. By default, the limit will
 619   * be to return the entire tag cloud list.
 620   *
 621   * The 'topic_count_text_callback' argument is a function, which given the count
 622   * of the posts  with that tag returns a text for the tooltip of the tag link.
 623   *
 624   * @todo Complete functionality.
 625   * @since 2.3.0
 626   *
 627   * @param array $tags List of tags.
 628   * @param string|array $args Optional, override default arguments.
 629   * @return string
 630   */
 631  function wp_generate_tag_cloud( $tags, $args = '' ) {
 632      global $wp_rewrite;
 633      $defaults = array(
 634          'smallest' => 8, 'largest' => 22, 'unit' => 'pt', 'number' => 0,
 635          'format' => 'flat', 'orderby' => 'name', 'order' => 'ASC',
 636          'topic_count_text_callback' => 'default_topic_count_text',
 637      );
 638  
 639      if ( !isset( $args['topic_count_text_callback'] ) && isset( $args['single_text'] ) && isset( $args['multiple_text'] ) ) {
 640          $body = 'return sprintf (
 641              __ngettext('.var_export($args['single_text'], true).', '.var_export($args['multiple_text'], true).', $count),
 642              number_format_i18n( $count ));';
 643          $args['topic_count_text_callback'] = create_function('$count', $body);
 644      }
 645  
 646      $args = wp_parse_args( $args, $defaults );
 647  
 648      extract( $args );
 649  
 650      if ( empty( $tags ) )
 651          return;
 652  
 653      // SQL cannot save you; this is a second (potentially different) sort on a subset of data.
 654      if ( 'name' == $orderby )
 655          uasort( $tags, create_function('$a, $b', 'return strnatcasecmp($a->name, $b->name);') );
 656      else
 657          uasort( $tags, create_function('$a, $b', 'return ($a->count > $b->count);') );
 658  
 659      if ( 'DESC' == $order )
 660          $tags = array_reverse( $tags, true );
 661      elseif ( 'RAND' == $order ) {
 662          $keys = array_rand( $tags, count( $tags ) );
 663          foreach ( $keys as $key )
 664              $temp[$key] = $tags[$key];
 665          $tags = $temp;
 666          unset( $temp );
 667      }
 668  
 669      if ( $number > 0 )
 670          $tags = array_slice($tags, 0, $number);
 671  
 672      $counts = array();
 673      foreach ( (array) $tags as $key => $tag )
 674          $counts[ $key ] = $tag->count;
 675  
 676      $min_count = min( $counts );
 677      $spread = max( $counts ) - $min_count;
 678      if ( $spread <= 0 )
 679          $spread = 1;
 680      $font_spread = $largest - $smallest;
 681      if ( $font_spread < 0 )
 682          $font_spread = 1;
 683      $font_step = $font_spread / $spread;
 684  
 685      $a = array();
 686  
 687      $rel = ( is_object( $wp_rewrite ) && $wp_rewrite->using_permalinks() ) ? ' rel="tag"' : '';
 688  
 689      foreach ( $tags as $key => $tag ) {
 690          $count = $counts[ $key ];
 691          $tag_link = '#' != $tag->link ? clean_url( $tag->link ) : '#';
 692          $tag_id = isset($tags[ $key ]->id) ? $tags[ $key ]->id : $key;
 693          $tag_name = $tags[ $key ]->name;
 694          $a[] = "<a href='$tag_link' class='tag-link-$tag_id' title='" . attribute_escape( $topic_count_text_callback( $count ) ) . "'$rel style='font-size: " .
 695              ( $smallest + ( ( $count - $min_count ) * $font_step ) )
 696              . "$unit;'>$tag_name</a>";
 697      }
 698  
 699      switch ( $format ) :
 700      case 'array' :
 701          $return =& $a;
 702          break;
 703      case 'list' :
 704          $return = "<ul class='wp-tag-cloud'>\n\t<li>";
 705          $return .= join( "</li>\n\t<li>", $a );
 706          $return .= "</li>\n</ul>\n";
 707          break;
 708      default :
 709          $return = join( "\n", $a );
 710          break;
 711      endswitch;
 712  
 713      return apply_filters( 'wp_generate_tag_cloud', $return, $tags, $args );
 714  }
 715  
 716  //
 717  // Helper functions
 718  //
 719  
 720  /**
 721   * Retrieve HTML list content for category list.
 722   *
 723   * @uses Walker_Category to create HTML list content.
 724   * @since 2.1.0
 725   * @see Walker_Category::walk() for parameters and return description.
 726   */
 727  function walk_category_tree() {
 728      $args = func_get_args();
 729      // the user's options are the third parameter
 730      if ( empty($args[2]['walker']) || !is_a($args[2]['walker'], 'Walker') )
 731          $walker = new Walker_Category;
 732      else
 733          $walker = $args[2]['walker'];
 734  
 735      return call_user_func_array(array( &$walker, 'walk' ), $args );
 736  }
 737  
 738  /**
 739   * Retrieve HTML dropdown (select) content for category list.
 740   *
 741   * @uses Walker_CategoryDropdown to create HTML dropdown content.
 742   * @since 2.1.0
 743   * @see Walker_CategoryDropdown::walk() for parameters and return description.
 744   */
 745  function walk_category_dropdown_tree() {
 746      $args = func_get_args();
 747      // the user's options are the third parameter
 748      if ( empty($args[2]['walker']) || !is_a($args[2]['walker'], 'Walker') )
 749          $walker = new Walker_CategoryDropdown;
 750      else
 751          $walker = $args[2]['walker'];
 752  
 753      return call_user_func_array(array( &$walker, 'walk' ), $args );
 754  }
 755  
 756  //
 757  // Tags
 758  //
 759  
 760  /**
 761   * Retrieve the link to the tag.
 762   *
 763   * @since 2.3.0
 764   * @uses apply_filters() Calls 'tag_link' with tag link and tag ID as parameters.
 765   *
 766   * @param int $tag_id Tag (term) ID.
 767   * @return string
 768   */
 769  function get_tag_link( $tag_id ) {
 770      global $wp_rewrite;
 771      $taglink = $wp_rewrite->get_tag_permastruct();
 772  
 773      $tag = &get_term( $tag_id, 'post_tag' );
 774      if ( is_wp_error( $tag ) )
 775          return $tag;
 776      $slug = $tag->slug;
 777  
 778      if ( empty( $taglink ) ) {
 779          $file = get_option( 'home' ) . '/';
 780          $taglink = $file . '?tag=' . $slug;
 781      } else {
 782          $taglink = str_replace( '%tag%', $slug, $taglink );
 783          $taglink = get_option( 'home' ) . user_trailingslashit( $taglink, 'category' );
 784      }
 785      return apply_filters( 'tag_link', $taglink, $tag_id );
 786  }
 787  
 788  /**
 789   * Retrieve the tags for a post.
 790   *
 791   * @since 2.3.0
 792   * @uses apply_filters() Calls 'get_the_tags' filter on the list of post tags.
 793   *
 794   * @param int $id Post ID.
 795   * @return array
 796   */
 797  function get_the_tags( $id = 0 ) {
 798      return apply_filters( 'get_the_tags', get_the_terms( $id, 'post_tag' ) );
 799  }
 800  
 801  /**
 802   * Retrieve the tags for a post formatted as a string.
 803   *
 804   * @since 2.3.0
 805   * @uses apply_filters() Calls 'the_tags' filter on string list of tags.
 806   *
 807   * @param string $before Optional. Before tags.
 808   * @param string $sep Optional. Between tags.
 809   * @param string $after Optional. After tags.
 810   * @return string
 811   */
 812  function get_the_tag_list( $before = '', $sep = '', $after = '' ) {
 813      return apply_filters( 'the_tags', get_the_term_list( 0, 'post_tag', $before, $sep, $after ) );
 814  }
 815  
 816  /**
 817   * Retrieve the tags for a post.
 818   *
 819   * @since 2.3.0
 820   *
 821   * @param string $before Optional. Before list.
 822   * @param string $sep Optional. Separate items using this.
 823   * @param string $after Optional. After list.
 824   * @return string
 825   */
 826  function the_tags( $before = 'Tags: ', $sep = ', ', $after = '' ) {
 827      return the_terms( 0, 'post_tag', $before, $sep, $after );
 828  }
 829  
 830  /**
 831   * Retrieve the terms of the taxonomy that are attached to the post.
 832   *
 833   * This function can only be used within the loop.
 834   *
 835   * @since 2.5.0
 836   *
 837   * @param int $id Post ID. Is not optional.
 838   * @param string $taxonomy Taxonomy name.
 839   * @return array|bool False on failure. Array of term objects on success.
 840   */
 841  function get_the_terms( $id = 0, $taxonomy ) {
 842      global $post;
 843  
 844       $id = (int) $id;
 845  
 846      if ( ! $id && ! in_the_loop() )
 847          return false; // in-the-loop function
 848  
 849      if ( !$id )
 850          $id = (int) $post->ID;
 851  
 852      $terms = get_object_term_cache( $id, $taxonomy );
 853      if ( false === $terms )
 854          $terms = wp_get_object_terms( $id, $taxonomy );
 855  
 856      if ( empty( $terms ) )
 857          return false;
 858  
 859      return $terms;
 860  }
 861  
 862  /**
 863   * Retrieve terms as a list with specified format.
 864   *
 865   * @since 2.5.0
 866   *
 867   * @param int $id Term ID.
 868   * @param string $taxonomy Taxonomy name.
 869   * @param string $before Optional. Before list.
 870   * @param string $sep Optional. Separate items using this.
 871   * @param string $after Optional. After list.
 872   * @return string
 873   */
 874  function get_the_term_list( $id = 0, $taxonomy, $before = '', $sep = '', $after = '' ) {
 875      $terms = get_the_terms( $id, $taxonomy );
 876  
 877      if ( is_wp_error( $terms ) )
 878          return $terms;
 879  
 880      if ( empty( $terms ) )
 881          return false;
 882  
 883      foreach ( $terms as $term ) {
 884          $link = get_term_link( $term, $taxonomy );
 885          if ( is_wp_error( $link ) )
 886              return $link;
 887          $term_links[] = '<a href="' . $link . '" rel="tag">' . $term->name . '</a>';
 888      }
 889  
 890      $term_links = apply_filters( "term_links-$taxonomy", $term_links );
 891  
 892      return $before . join( $sep, $term_links ) . $after;
 893  }
 894  
 895  /**
 896   * Display the terms in a list.
 897   *
 898   * @since 2.5.0
 899   *
 900   * @param int $id Term ID.
 901   * @param string $taxonomy Taxonomy name.
 902   * @param string $before Optional. Before list.
 903   * @param string $sep Optional. Separate items using this.
 904   * @param string $after Optional. After list.
 905   * @return null|bool False on WordPress error. Returns null when displaying.
 906   */
 907  function the_terms( $id, $taxonomy, $before = '', $sep = '', $after = '' ) {
 908      $return = get_the_term_list( $id, $taxonomy, $before, $sep, $after );
 909      if ( is_wp_error( $return ) )
 910          return false;
 911      else
 912          echo $return;
 913  }
 914  
 915  /**
 916   * Check if the current post has any of given tags.
 917   *
 918   * The given tags are checked against the post's tags' term_ids, names and slugs.
 919   * Tags given as integers will only be checked against the post's tags' term_ids.
 920   * If no tags are given, determines if post has any tags.
 921   *
 922   * Prior to v2.7 of WordPress, tags given as integers would also be checked against the post's tags' names and slugs (in addition to term_ids)
 923   * Prior to v2.7, this function could only be used in the WordPress Loop.
 924   * As of 2.7, the function can be used anywhere if it is provided a post ID or post object.
 925   *
 926   * @since 2.6.0
 927   *
 928   * @uses is_object_in_term()
 929   *
 930   * @param string|int|array $tag Optional. The tag name/term_id/slug or array of them to check for.
 931   * @param int|post object Optional.  Post to check instead of the current post. @since 2.7.0
 932   * @return bool True if the current post has any of the the given tags (or any tag, if no tag specified).
 933   */
 934  function has_tag( $tag = '', $_post = null ) {
 935      if ( $_post ) {
 936          $_post = get_post( $_post );
 937      } else {
 938          $_post =& $GLOBALS['post'];
 939      }
 940  
 941      if ( !$_post )
 942          return false;
 943  
 944      $r = is_object_in_term( $_post->ID, 'post_tag', $tag );
 945      if ( is_wp_error( $r ) )
 946          return false;
 947      return $r;
 948  }
 949  
 950  ?>