Category Template Hierarchy

Adds several new templates to the template hierarchy:

• child-of-category-{slug}.php
• category-{slug}.php
• child-of-category-{id}.php
• category-{term_id}.php
• parent-category.php
• child-category.php
• category.php
• archive.php
• index.php

This greatly extends the native hierarchy of theme templates with regard to
categories. Theme developers can now easily create separate templates for
categories with children, with parents, and children of specific parents.

Additionally makes available four (4) new conditional template tags:

• is_child_category();
• is_parent_category();
• is_child_of_category();
• is_parent_of_category();

These functions are available for use in any theme or plugin as along as this
plugin is active. For detailed documentation of these functions see the
‘Developer Notes: Conditional Tags’ section of this readme file.

Note: This plugin does not actually create parent-category.php, child-category.php
or any of their related templates – rather it modifies the native template hierarchy
to allow theme developers to create specific templates for parent and child categories.

Developer Notes: Template Hierarchy

What follows are is the modified list of templates available for category pages.
These expand upon the native Template Hierarchy.

• child-of-category-{slug}.php
• category-{slug}.php
• child-of-category-{id}.php
• category-{term_id}.php
• parent-category.php
• child-category.php
• category.php
• archive.php
• index.php

The parent and child templates only become available if the current category is
a parent or a child respectively.

Note: This plugin does not actually create parent-category.php, child-category.php
or any of their related templates – rather it modifies the native template hierarchy
to allow theme developers to create specific templates for parent and child categories.

Developer Notes: Conditional Tags

With this plugin comes two additional conditional tags
which behave much like any other in WordPress. In a similar fashion to how one
might use is_category() or cat_is_ancestory_of(),
developers may, with this plugin, use the following functions:

• is_parent_category()
• is_child_category()
• is_child_of_category()
• is_parent_of_category()

Description (part 1)

The is_parent_category() and is_child_category() conditional tags check if
the page being displayed (or passed as an argument) is of a category that has
children (e.g. is a parent category) has a parent (is a child), respectively.
They are boolean functions, meaning they return either TRUE or FALSE.

Usage

<?php is_parent_category( $category ); ?>
<?php is_child_category( $category ); ?>

Parameters

$category (integer/string/object) (optional) Category ID, Category Slug, Category Object. Default: Current Category

Note: Unlike is_category(), these functions will not take arrays of categories or category titles. I’ll work on that. Sorry.

Return Values

(boolean) True on success, false on failure.

Examples

is_parent_category()
is_child_category()
// When any parent/child category archive page is being displayed

is_parent_category( '9' );
is_child_category( '9' );
// When the archive page for Category 9 is being displayed AND its a parent/child.

is_parent_category( 'blue-cheese' );
is_child_category( 'blue-cheese' );
// When the archive page for the Category with Category Slug "blue-cheese" is being displayed AND its a parent/child.

Description (part 2)

The is_parent_of_category() and is_child_of_category() conditional tags
check if a given category has a parent or child relationship to the current
category or a category passed as its second parameter. They are
boolean functions, meaning they return either TRUE or FALSE.

Usage

<?php is_parent_of_category($child_category, $parent_category, $direct_descendant); ?>
<?php is_child_of_category($parent_category, $child_category, $direct_descendant);?>

Parameters

(object/string/integer) (required) Category of the would-be parent/child respectively.
(object/string/integer) (optional) Category of the would-be child/parent respectfully. Default: Current Category
(boolean) (optional) Whether or not the child should be a direct child of the parent. Default: True
*

Return Values

(boolean) If the $direct_descendant flag set to true, function returns true if the child is a direct descendant of the parent, if child is no direct it will return false. If $direct_descendant is set to false it will return the same results as cat_is_ancestor_of().

Examples

The following function will return True…

is_child_of_category(0);
// When a top level category is being displayed, zero being the parent id value for top level categories (e.g. categories with no parents).

is_child_of_category(12);
// When the current category is a direct child of the category whose ID is '12'.

is_child_of_category('tv-shows')
// When the current category is a direct child of the category with the slug 'tv-shows' (can also be category ID's).

is_child_of_category('tv-shows', 'dexter');
// When the category with slug 'dexter' is a direct child of the category with the slug 'tv-shows' (can also be category ID's). This may come in handy when manipulating categories while not in a category template.

is_child_of_category('tv-shows', 'dexter', false);
// When the category with the slug 'dexter' is a descendant of the category 'tv-shows' at any level. (uses cat_is_ancestor_of())

is_child_of_category('tv-shows', null, false);
// When the current category is a descendant of the 'tv-shows' category at any level. (uses cat_is_ancestor_of())

is_parent_of_category(13);
// When the current category is the direct parent of a category with the ID '13'.

is_parent_of_category('dexter');
// When the current category is the direct parent of the category with the slug 'dexter'.

Backward Compatibility

The changes this plugin makes to the template hierarchy are significantly different
from that in 1.0.5 and before. If you prefer to use that version please find it
in the Older Versions in the WordPress plugins directory, it is tagged as 1.0.5.

While I do not actively support to QA the older version, I would gladly take a
look at any future bugs that crop up and are reported.