Function: Adds a new term to the database if it does not already exist.

Function: Checks whether a category exists.

Function: Gets category object for given ID and ‘edit’ filter context.

Function: Adds a new category to the database if it does not already exist.

Function: Creates categories for the given post.

Function: Aliases wp_insert_category() with minimal args.

Function: Checks whether a post tag with a given name exists.

Function: Adds a new tag to the database if it does not already exist.

Function: Gets comma-separated list of tags available to edit.