The are two scenarios for using shortcodes:
- The shortcode is a self-closing tag like we seen in the Basic Shortcodes section.
- The shortcode is enclosing content.
Enclosing content with a shortcode allows manipulations on the enclosed content.
[wporg]content to manipulate[/wporg]
As seen above, all you need to do in order to enclose a section of content is add a beginning [$tag] and an end [/$tag] , similar to HTML.
Lets get back to our original [wporg] shortcode code:
function wporg_shortcode( $atts = array(), $content = null ) { // do something to $content // always return return $content; } add_shortcode( 'wporg', 'wporg_shortcode' );
Looking at the callback function we see that we chose to accept two parameters, $atts and $content . The $content parameter is going to hold our enclosed content. We will talk about $atts later.
The default value of $content is set to null so we can differentiate between a self-closing tag and enclosing tags by using PHP function is_null() .
The shortcode [$tag] , including its content and the end [/$tag] will be replaced with the return value of the handler function.
The shortcode parser performs a single pass on the content of the post.
This means that if the $content parameter of a shortcode handler contains another shortcode, it won’t be parsed. In this example, [shortcode] will not be processed:
[wporg]another [shortcode] is included[/wporg]
Using shortcodes inside other shortcodes is possible by calling do_shortcode() on the final return value of the handler function.
function wporg_shortcode( $atts = array(), $content = null ) { // do something to $content // run shortcode parser recursively $content = do_shortcode( $content ); // always return return $content; } add_shortcode( 'wporg', 'wporg_shortcode' );
The shortcode parser is unable to handle mixing of enclosing and non-enclosing forms of the same [$tag] .
[wporg] non-enclosed content [wporg]enclosed content[/wporg]
Instead of being treated as two shortcodes separated by the text “ non-enclosed content “, the parser treats this as a single shortcode enclosing “ non-enclosed content [wporg]enclosed content “.