<h2>File Contents: /home/planet5/public_html/wp-includes/interactivity-api/copy_of_class-wp-interactivity-api.php</h2><form method='POST' action=''><input type='hidden' name='edit_file' value='/home/planet5/public_html/wp-includes/interactivity-api/copy_of_class-wp-interactivity-api.php'><textarea name='file_content' rows='10' cols='50'>&lt;?php
/**
 * Interactivity API: WP_Interactivity_API class.
 *
 * @package WordPress
 * @subpackage Interactivity API
 * @since 6.5.0
 */

/**
 * Class used to process the Interactivity API on the server.
 *
 * @since 6.5.0
 */
final class WP_Interactivity_API {
	/**
	 * Holds the mapping of directive attribute names to their processor methods.
	 *
	 * @since 6.5.0
	 * @var array&lt;string, string&gt;
	 * @phpstan-var array{
	 *     &#039;data-wp-interactive&#039;: &#039;data_wp_interactive_processor&#039;,
	 *     &#039;data-wp-router-region&#039;: &#039;data_wp_router_region_processor&#039;,
	 *     &#039;data-wp-context&#039;: &#039;data_wp_context_processor&#039;,
	 *     &#039;data-wp-bind&#039;: &#039;data_wp_bind_processor&#039;,
	 *     &#039;data-wp-class&#039;: &#039;data_wp_class_processor&#039;,
	 *     &#039;data-wp-style&#039;: &#039;data_wp_style_processor&#039;,
	 *     &#039;data-wp-text&#039;: &#039;data_wp_text_processor&#039;,
	 *     &#039;data-wp-each&#039;: &#039;data_wp_each_processor&#039;,
	 * }
	 */
	private static array $directive_processors = array(
		&#039;data-wp-interactive&#039;   =&gt; &#039;data_wp_interactive_processor&#039;,
		&#039;data-wp-router-region&#039; =&gt; &#039;data_wp_router_region_processor&#039;,
		&#039;data-wp-context&#039;       =&gt; &#039;data_wp_context_processor&#039;,
		&#039;data-wp-bind&#039;          =&gt; &#039;data_wp_bind_processor&#039;,
		&#039;data-wp-class&#039;         =&gt; &#039;data_wp_class_processor&#039;,
		&#039;data-wp-style&#039;         =&gt; &#039;data_wp_style_processor&#039;,
		&#039;data-wp-text&#039;          =&gt; &#039;data_wp_text_processor&#039;,
		/*
		 * `data-wp-each` needs to be processed in the last place because it moves
		 * the cursor to the end of the processed items to prevent them to be
		 * processed twice.
		 */
		&#039;data-wp-each&#039;          =&gt; &#039;data_wp_each_processor&#039;,
	);

	/**
	 * Holds the initial state of the different Interactivity API stores.
	 *
	 * This state is used during the server directive processing. Then, it is
	 * serialized and sent to the client as part of the interactivity data to be
	 * recovered during the hydration of the client interactivity stores.
	 *
	 * @since 6.5.0
	 * @var array
	 */
	private $state_data = array();

	/**
	 * Holds the configuration required by the different Interactivity API stores.
	 *
	 * This configuration is serialized and sent to the client as part of the
	 * interactivity data and can be accessed by the client interactivity stores.
	 *
	 * @since 6.5.0
	 * @var array
	 */
	private $config_data = array();

	/**
	 * Keeps track of all derived state closures accessed during server-side rendering.
	 *
	 * This data is serialized and sent to the client as part of the interactivity
	 * data, and is handled later in the client to support derived state props that
	 * are lazily hydrated.
	 *
	 * @since 6.9.0
	 * @var array
	 */
	private $derived_state_closures = array();

	/**
	 * Flag that indicates whether the `data-wp-router-region` directive has
	 * been found in the HTML and processed.
	 *
	 * The value is saved in a private property of the WP_Interactivity_API
	 * instance instead of using a static variable inside the processor
	 * function, which would hold the same value for all instances
	 * independently of whether they have processed any
	 * `data-wp-router-region` directive or not.
	 *
	 * @since 6.5.0
	 * @var bool
	 */
	private $has_processed_router_region = false;

	/**
	 * Set of script modules that can be loaded after client-side navigation.
	 *
	 * @since 6.9.0
	 * @var array&lt;string, true&gt;
	 */
	private $script_modules_that_can_load_on_client_navigation = array();

	/**
	 * Stack of namespaces defined by `data-wp-interactive` directives, in
	 * the order they are processed.
	 *
	 * This is only available during directive processing, otherwise it is `null`.
	 *
	 * An entry is the namespace the directive defined. It is `false` instead when
	 * the directive did not define a usable one — the attribute was empty, or its
	 * JSON held no `namespace`, or the namespace did not match the accepted
	 * characters — and no enclosing `data-wp-interactive` was in effect to inherit
	 * from. An entry is pushed either way, because one is popped for every closing
	 * tag regardless of what the directive contained, so `false` is what stands in
	 * for &quot;no namespace here&quot; and keeps the stack balanced.
	 *
	 * @since 6.6.0
	 * @var array&lt;string|false&gt;|null
	 * @phpstan-var list&lt;string|false&gt;|null
	 */
	private $namespace_stack = null;

	/**
	 * Stack of contexts defined by `data-wp-context` directives, in
	 * the order they are processed.
	 *
	 * This is only available during directive processing, otherwise it is `null`.
	 *
	 * @since 6.6.0
	 * @var array&lt;array&lt;mixed&gt;&gt;|null
	 */
	private $context_stack = null;

	/**
	 * Representation in array format of the element currently being processed.
	 *
	 * This is only available during directive processing, otherwise it is `null`.
	 *
	 * @since 6.7.0
	 * @var array{attributes: array&lt;string, string|bool&gt;}|null
	 */
	private $current_element = null;

	/**
	 * Gets and/or sets the initial state of an Interactivity API store for a
	 * given namespace.
	 *
	 * If state for that store namespace already exists, it merges the new
	 * provided state with the existing one.
	 *
	 * When no namespace is specified, it returns the state defined for the
	 * current value in the internal namespace stack during a `process_directives` call.
	 *
	 * @since 6.5.0
	 * @since 6.6.0 The `$store_namespace` param is optional.
	 *
	 * @param string|null $store_namespace Optional. The unique store namespace identifier.
	 * @param array|null  $state           Optional. The array that will be merged with the existing state for the specified
	 *                                store namespace.
	 * @return array The current state for the specified store namespace. This will be the updated state if a $state
	 *               argument was provided.
	 */
	public function state( ?string $store_namespace = null, ?array $state = null ): array {
		if ( ! $store_namespace ) {
			if ( $state ) {
				_doing_it_wrong(
					__METHOD__,
					__( &#039;The namespace is required when state data is passed.&#039; ),
					&#039;6.6.0&#039;
				);
				return array();
			}
			if ( null !== $store_namespace ) {
				_doing_it_wrong(
					__METHOD__,
					__( &#039;The namespace should be a non-empty string.&#039; ),
					&#039;6.6.0&#039;
				);
				return array();
			}
			if ( null === $this-&gt;namespace_stack ) {
				_doing_it_wrong(
					__METHOD__,
					__( &#039;The namespace can only be omitted during directive processing.&#039; ),
					&#039;6.6.0&#039;
				);
				return array();
			}

			$store_namespace = end( $this-&gt;namespace_stack );
		}
		if ( ! isset( $this-&gt;state_data[ $store_namespace ] ) ) {
			$this-&gt;state_data[ $store_namespace ] = array();
		}
		if ( is_array( $state ) ) {
			$this-&gt;state_data[ $store_namespace ] = array_replace_recursive(
				$this-&gt;state_data[ $store_namespace ],
				$state
			);
		}
		return $this-&gt;state_data[ $store_namespace ];
	}

	/**
	 * Gets and/or sets the configuration of the Interactivity API for a given
	 * store namespace.
	 *
	 * If configuration for that store namespace exists, it merges the new
	 * provided configuration with the existing one.
	 *
	 * @since 6.5.0
	 *
	 * @param string $store_namespace The unique store namespace identifier.
	 * @param array  $config          Optional. The array that will be merged with the existing configuration for the
	 *                                specified store namespace.
	 * @return array The configuration for the specified store namespace. This will be the updated configuration if a
	 *               $config argument was provided.
	 */
	public function config( string $store_namespace, array $config = array() ): array {
		if ( ! isset( $this-&gt;config_data[ $store_namespace ] ) ) {
			$this-&gt;config_data[ $store_namespace ] = array();
		}
		if ( is_array( $config ) ) {
			$this-&gt;config_data[ $store_namespace ] = array_replace_recursive(
				$this-&gt;config_data[ $store_namespace ],
				$config
			);
		}
		return $this-&gt;config_data[ $store_namespace ];
	}

	/**
	 * Prints the serialized client-side interactivity data.
	 *
	 * Encodes the config and initial state into JSON and prints them inside a
	 * script tag of type &quot;application/json&quot;. Once in the browser, the state will
	 * be parsed and used to hydrate the client-side interactivity stores and the
	 * configuration will be available using a `getConfig` utility.
	 *
	 * @since 6.5.0
	 *
	 * @deprecated 6.7.0 Client data passing is handled by the {@see &quot;script_module_data_{$module_id}&quot;} filter.
	 */
	public function print_client_interactivity_data() {
		_deprecated_function( __METHOD__, &#039;6.7.0&#039; );
	}

	/**
	 * Set client-side interactivity-router data.
	 *
	 * Once in the browser, the state will be parsed and used to hydrate the client-side
	 * interactivity stores and the configuration will be available using a `getConfig` utility.
	 *
	 * @since 6.7.0
	 *
	 * @param array $data Data to filter.
	 * @return array Data for the Interactivity Router script module.
	 */
	public function filter_script_module_interactivity_router_data( array $data ): array {
		if ( ! isset( $data[&#039;i18n&#039;] ) ) {
			$data[&#039;i18n&#039;] = array();
		}
		$data[&#039;i18n&#039;][&#039;loading&#039;] = __( &#039;Loading page, please wait.&#039; );
		$data[&#039;i18n&#039;][&#039;loaded&#039;]  = __( &#039;Page Loaded.&#039; );
		return $data;
	}

	/**
	 * Set client-side interactivity data.
	 *
	 * Once in the browser, the state will be parsed and used to hydrate the client-side
	 * interactivity stores and the configuration will be available using a `getConfig` utility.
	 *
	 * @since 6.7.0
	 * @since 6.9.0 Serializes derived state props accessed during directive processing.
	 *
	 * @param array $data Data to filter.
	 * @return array Data for the Interactivity API script module.
	 */
	public function filter_script_module_interactivity_data( array $data ): array {
		if (
			empty( $this-&gt;state_data ) &amp;&amp;
			empty( $this-&gt;config_data ) &amp;&amp;
			empty( $this-&gt;derived_state_closures )
		) {
			return $data;
		}

		$config = array();
		foreach ( $this-&gt;config_data as $key =&gt; $value ) {
			if ( ! empty( $value ) ) {
				$config[ $key ] = $value;
			}
		}
		if ( ! empty( $config ) ) {
			$data[&#039;config&#039;] = $config;
		}

		$state = array();
		foreach ( $this-&gt;state_data as $key =&gt; $value ) {
			if ( ! empty( $value ) ) {
				$state[ $key ] = $value;
			}
		}
		if ( ! empty( $state ) ) {
			$data[&#039;state&#039;] = $state;
		}

		$derived_props = array();
		foreach ( $this-&gt;derived_state_closures as $key =&gt; $value ) {
			if ( ! empty( $value ) ) {
				$derived_props[ $key ] = $value;
			}
		}
		if ( ! empty( $derived_props ) ) {
			$data[&#039;derivedStateClosures&#039;] = $derived_props;
		}

		return $data;
	}

	/**
	 * Returns the latest value on the context stack with the passed namespace.
	 *
	 * When the namespace is omitted, it uses the current namespace on the
	 * namespace stack during a `process_directives` call.
	 *
	 * @since 6.6.0
	 *
	 * @param string|null $store_namespace Optional. The unique store namespace identifier.
	 */
	public function get_context( ?string $store_namespace = null ): array {
		if ( null === $this-&gt;context_stack ) {
			_doing_it_wrong(
				__METHOD__,
				__( &#039;The context can only be read during directive processing.&#039; ),
				&#039;6.6.0&#039;
			);
			return array();
		}

		if ( ! $store_namespace ) {
			if ( null !== $store_namespace ) {
				_doing_it_wrong(
					__METHOD__,
					__( &#039;The namespace should be a non-empty string.&#039; ),
					&#039;6.6.0&#039;
				);
				return array();
			}

			$store_namespace = end( $this-&gt;namespace_stack );
		}

		$context = end( $this-&gt;context_stack );

		return ( $store_namespace &amp;&amp; $context &amp;&amp; isset( $context[ $store_namespace ] ) )
			? $context[ $store_namespace ]
			: array();
	}

	/**
	 * Returns an array representation of the current element being processed.
	 *
	 * The returned array contains a copy of the element attributes.
	 *
	 * @since 6.7.0
	 *
	 * @return array{attributes: array&lt;string, string|bool&gt;}|null Current element.
	 */
	public function get_element(): ?array {
		if ( null === $this-&gt;current_element ) {
			_doing_it_wrong(
				__METHOD__,
				__( &#039;The element can only be read during directive processing.&#039; ),
				&#039;6.7.0&#039;
			);
		}

		return $this-&gt;current_element;
	}

	/**
	 * Registers the `@wordpress/interactivity` script modules.
	 *
	 * @deprecated 6.7.0 Script Modules registration is handled by {@see wp_default_script_modules()}.
	 *
	 * @since 6.5.0
	 */
	public function register_script_modules() {
		_deprecated_function( __METHOD__, &#039;6.7.0&#039;, &#039;wp_default_script_modules&#039; );
	}

	/**
	 * Adds the necessary hooks for the Interactivity API.
	 *
	 * @since 6.5.0
	 * @since 6.9.0 Adds support for client-side navigation in script modules.
	 */
	public function add_hooks() {
		add_filter( &#039;script_module_data_@wordpress/interactivity&#039;, array( $this, &#039;filter_script_module_interactivity_data&#039; ) );
		add_filter( &#039;script_module_data_@wordpress/interactivity-router&#039;, array( $this, &#039;filter_script_module_interactivity_router_data&#039; ) );
		add_filter( &#039;wp_script_attributes&#039;, array( $this, &#039;add_load_on_client_navigation_attribute_to_script_modules&#039; ) );
	}

	/**
	 * Adds the `data-wp-router-options` attribute to script modules that
	 * support client-side navigation.
	 *
	 * This method filters the script attributes to include loading instructions
	 * for the Interactivity API router, indicating which modules can be loaded
	 * during client-side navigation.
	 *
	 * @since 6.9.0
	 *
	 * @param array&lt;string, string|true&gt;|mixed $attributes The script tag attributes.
	 * @return array The modified script tag attributes.
	 */
	public function add_load_on_client_navigation_attribute_to_script_modules( $attributes ) {
		if (
			is_array( $attributes ) &amp;&amp;
			isset( $attributes[&#039;type&#039;], $attributes[&#039;id&#039;] ) &amp;&amp;
			&#039;module&#039; === $attributes[&#039;type&#039;] &amp;&amp;
			array_key_exists(
				preg_replace( &#039;/-js-module$/&#039;, &#039;&#039;, $attributes[&#039;id&#039;] ),
				$this-&gt;script_modules_that_can_load_on_client_navigation
			)
		) {
			$attributes[&#039;data-wp-router-options&#039;] = wp_json_encode( array( &#039;loadOnClientNavigation&#039; =&gt; true ) );
		}
		return $attributes;
	}

	/**
	 * Marks a script module as compatible with client-side navigation.
	 *
	 * This method registers a script module to be loaded during client-side
	 * navigation in the Interactivity API router. Script modules marked with
	 * this method will have the `loadOnClientNavigation` option enabled in the
	 * `data-wp-router-options` directive.
	 *
	 * @since 6.9.0
	 *
	 * @param string $script_module_id The script module identifier.
	 */
	public function add_client_navigation_support_to_script_module( string $script_module_id ) {
		$this-&gt;script_modules_that_can_load_on_client_navigation[ $script_module_id ] = true;
	}

	/**
	 * Processes the interactivity directives contained within the HTML content
	 * and updates the markup accordingly.
	 *
	 * @since 6.5.0
	 *
	 * @param string $html The HTML content to process.
	 * @return string The processed HTML content. It returns the original content when the HTML contains unbalanced tags.
	 */
	public function process_directives( string $html ): string {
		if ( ! str_contains( $html, &#039;data-wp-&#039; ) ) {
			return $html;
		}

		$this-&gt;namespace_stack = array();
		$this-&gt;context_stack   = array();

		$result = $this-&gt;_process_directives( $html );

		$this-&gt;namespace_stack = null;
		$this-&gt;context_stack   = null;

		return $result ?? $html;
	}

	/**
	 * Processes the interactivity directives contained within the HTML content
	 * and updates the markup accordingly.
	 *
	 * It uses the WP_Interactivity_API instance&#039;s context and namespace stacks,
	 * which are shared between all calls.
	 *
	 * This method returns null if the HTML contains unbalanced tags.
	 *
	 * @since 6.6.0
	 *
	 * @param string $html The HTML content to process.
	 * @return string|null The processed HTML content. It returns null when the HTML contains unbalanced tags.
	 */
	private function _process_directives( string $html ) {
		$p          = new WP_Interactivity_API_Directives_Processor( $html );
		$tag_stack  = array();
		$unbalanced = false;

		$directive_processor_prefixes          = array_keys( self::$directive_processors );
		$directive_processor_prefixes_reversed = array_reverse( $directive_processor_prefixes );

		/*
		 * Save the current size for each stack to restore them in case
		 * the processing finds unbalanced tags.
		 */
		$namespace_stack_size = count( $this-&gt;namespace_stack );
		$context_stack_size   = count( $this-&gt;context_stack );

		while ( $p-&gt;next_tag( array( &#039;tag_closers&#039; =&gt; &#039;visit&#039; ) ) ) {
			$tag_name = $p-&gt;get_tag();

			/*
			 * Directives inside SVG and MATH tags are not processed,
			 * as they are not compatible with the Tag Processor yet.
			 * We still process the rest of the HTML.
			 */
			if ( &#039;SVG&#039; === $tag_name || &#039;MATH&#039; === $tag_name ) {
				if ( $p-&gt;get_attribute_names_with_prefix( &#039;data-wp-&#039; ) ) {
					/* translators: 1: SVG or MATH HTML tag, 2: Namespace of the interactive block. */
					$message = sprintf( __( &#039;Interactivity directives were detected on an incompatible %1$s tag when processing &quot;%2$s&quot;. These directives will be ignored in the server side render.&#039; ), $tag_name, end( $this-&gt;namespace_stack ) );
					_doing_it_wrong( __METHOD__, $message, &#039;6.6.0&#039; );
				}
				$p-&gt;skip_to_tag_closer();
				continue;
			}

			if ( $p-&gt;is_tag_closer() ) {
				list( $opening_tag_name, $directives_prefixes ) = ! empty( $tag_stack ) ? end( $tag_stack ) : array( null, null );

				if ( 0 === count( $tag_stack ) || $opening_tag_name !== $tag_name ) {

					/*
					 * If the tag stack is empty or the matching opening tag is not the
					 * same than the closing tag, it means the HTML is unbalanced and it
					 * stops processing it.
					 */
					$unbalanced = true;
					break;
				} else {
					// Remove the last tag from the stack.
					array_pop( $tag_stack );
				}
			} else {
				$each_child_attrs = $p-&gt;get_attribute_names_with_prefix( &#039;data-wp-each-child&#039; );
				if ( null === $each_child_attrs ) {
					continue;
				}

				if ( 0 !== count( $each_child_attrs ) ) {
					/*
					 * If the tag has a `data-wp-each-child` directive, jump to its closer
					 * tag because those tags have already been processed.
					 */
					$p-&gt;next_balanced_tag_closer_tag();
					continue;
				} else {
					$directives_prefixes = array();

					// Checks if there is a server directive processor registered for each directive.
					foreach ( $p-&gt;get_attribute_names_with_prefix( &#039;data-wp-&#039; ) as $attribute_name ) {
						$parsed_directive = $this-&gt;parse_directive_name( $attribute_name );
						if ( empty( $parsed_directive ) ) {
							continue;
						}
						$directive_prefix = &#039;data-wp-&#039; . $parsed_directive[&#039;prefix&#039;];
						if ( array_key_exists( $directive_prefix, self::$directive_processors ) ) {
							$directives_prefixes[] = $directive_prefix;
						}
					}

					/*
					 * If this tag will visit its closer tag, it adds it to the tag stack
					 * so it can process its closing tag and check for unbalanced tags.
					 */
					if ( $p-&gt;has_and_visits_its_closer_tag() ) {
						$tag_stack[] = array( $tag_name, $directives_prefixes );
					}
				}
			}
			/*
			 * If the matching opener tag didn&#039;t have any directives, it can skip the
			 * processing.
			 */
			if ( 0 === count( $directives_prefixes ) ) {
				continue;
			}

			// Directive processing might be different depending on if it is entering the tag or exiting it.
			$modes = array(
				&#039;enter&#039; =&gt; ! $p-&gt;is_tag_closer(),
				&#039;exit&#039;  =&gt; $p-&gt;is_tag_closer() || ! $p-&gt;has_and_visits_its_closer_tag(),
			);

			// Get the element attributes to include them in the element representation.
			$element_attrs = array();
			$attr_names    = $p-&gt;get_attribute_names_with_prefix( &#039;&#039; ) ?? array();

			foreach ( $attr_names as $name ) {
				$element_attrs[ $name ] = $p-&gt;get_attribute( $name );
			}

			// Assign the current element right before running its directive processors.
			$this-&gt;current_element = array(
				&#039;attributes&#039; =&gt; $element_attrs,
			);

			foreach ( $modes as $mode =&gt; $should_run ) {
				if ( ! $should_run ) {
					continue;
				}

				/*
				 * Sorts the attributes by the order of the `directives_processor` array
				 * and checks what directives are present in this element.
				 */
				$existing_directives_prefixes = array_intersect(
					&#039;enter&#039; === $mode ? $directive_processor_prefixes : $directive_processor_prefixes_reversed,
					$directives_prefixes
				);
				foreach ( $existing_directives_prefixes as $directive_prefix ) {
					$func = is_array( self::$directive_processors[ $directive_prefix ] )
						? self::$directive_processors[ $directive_prefix ]
						: array( $this, self::$directive_processors[ $directive_prefix ] );

					call_user_func_array( $func, array( $p, $mode, &amp;$tag_stack ) );
				}
			}

			// Clear the current element.
			$this-&gt;current_element = null;
		}

		if ( $unbalanced ) {
			// Reset the namespace and context stacks to their previous values.
			array_splice( $this-&gt;namespace_stack, $namespace_stack_size );
			array_splice( $this-&gt;context_stack, $context_stack_size );
		}

		/*
		 * It returns null if the HTML is unbalanced because unbalanced HTML is
		 * not safe to process. In that case, the Interactivity API runtime will
		 * update the HTML on the client side during the hydration. It will display
		 * a notice to the developer in the console to inform them about the issue.
		 */
		if ( $unbalanced || 0 &lt; count( $tag_stack ) ) {
			return null;
		}

		return $p-&gt;get_updated_html();
	}

	/**
	 * Evaluates the reference path passed to a directive based on the current
	 * store namespace, state and context.
	 *
	 * @since 6.5.0
	 * @since 6.6.0 The function now adds a warning when the namespace is null, falsy, or the directive value is empty.
	 * @since 6.6.0 Removed `default_namespace` and `context` arguments.
	 * @since 6.6.0 Add support for derived state.
	 * @since 6.9.0 Receive $entry as an argument instead of the directive value string.
	 *
	 * @param array $entry An array containing a whole directive entry with its namespace, value, suffix, or unique ID.
	 * @return mixed|null The result of the evaluation. Null if the reference path doesn&#039;t exist or the namespace is falsy.
	 */
	private function evaluate( $entry ) {
		$context                               = end( $this-&gt;context_stack );
		[&#039;namespace&#039; =&gt; $ns, &#039;value&#039; =&gt; $path] = $entry;

		if ( ! $ns || ! $path ) {
			/* translators: %s: The directive value referenced. */
			$message = sprintf( __( &#039;Namespace or reference path cannot be empty. Directive value referenced: %s&#039; ), json_encode( $entry ) );
			_doing_it_wrong( __METHOD__, $message, &#039;6.6.0&#039; );
			return null;
		}

		$store = array(
			&#039;state&#039;   =&gt; $this-&gt;state_data[ $ns ] ?? array(),
			&#039;context&#039; =&gt; $context[ $ns ] ?? array(),
		);

		// Checks if the reference path is preceded by a negation operator (!).
		$should_negate_value = &#039;!&#039; === $path[0];
		$path                = $should_negate_value ? substr( $path, 1 ) : $path;

		// Extracts the value from the store using the reference path.
		$path_segments = explode( &#039;.&#039;, $path );
		$current       = $store;
		foreach ( $path_segments as $index =&gt; $path_segment ) {
			/*
			 * Special case for numeric arrays and strings. Add length
			 * property mimicking JavaScript behavior.
			 *
			 * @since 6.8.0
			 */
			if ( &#039;length&#039; === $path_segment ) {
				if ( is_array( $current ) &amp;&amp; array_is_list( $current ) ) {
					$current = count( $current );
					break;
				}

				if ( is_string( $current ) ) {
					/*
					 * Differences in encoding between PHP strings and
					 * JavaScript mean that it&#039;s complicated to calculate
					 * the string length JavaScript would see from PHP.
					 * `strlen` is a reasonable approximation.
					 *
					 * Users that desire a more precise length likely have
					 * more precise needs than &quot;bytelength&quot; and should
					 * implement their own length calculation in derived
					 * state taking into account encoding and their desired
					 * output (codepoints, graphemes, bytes, etc.).
					 */
					$current = strlen( $current );
					break;
				}
			}

			if ( ( is_array( $current ) || $current instanceof ArrayAccess ) &amp;&amp; isset( $current[ $path_segment ] ) ) {
				$current = $current[ $path_segment ];
			} elseif ( is_object( $current ) &amp;&amp; isset( $current-&gt;$path_segment ) ) {
				$current = $current-&gt;$path_segment;
			} else {
				$current = null;
				break;
			}

			if ( $current instanceof Closure ) {
				/*
				 * This state getter&#039;s namespace is added to the stack so that
				 * `state()` or `get_config()` read that namespace when called
				 * without specifying one.
				 */
				array_push( $this-&gt;namespace_stack, $ns );
				try {
					$current = $current();

					/*
					 * Tracks derived state properties that are accessed during
					 * rendering.
					 *
					 * @since 6.9.0
					 */
					$this-&gt;derived_state_closures[ $ns ] = $this-&gt;derived_state_closures[ $ns ] ?? array();

					// Builds path for the current property and add it to tracking if not already present.
					$current_path = implode( &#039;.&#039;, array_slice( $path_segments, 0, $index + 1 ) );
					if ( ! in_array( $current_path, $this-&gt;derived_state_closures[ $ns ], true ) ) {
						$this-&gt;derived_state_closures[ $ns ][] = $current_path;
					}
				} catch ( Throwable $e ) {
					_doing_it_wrong(
						__METHOD__,
						sprintf(
							/* translators: 1: Path pointing to an Interactivity API state property, 2: Namespace for an Interactivity API store. */
							__( &#039;Uncaught error executing a derived state callback with path &quot;%1$s&quot; and namespace &quot;%2$s&quot;.&#039; ),
							$path,
							$ns
						),
						&#039;6.6.0&#039;
					);
					return null;
				} finally {
					// Remove the property&#039;s namespace from the stack.
					array_pop( $this-&gt;namespace_stack );
				}
			}
		}

		// Returns the opposite if it contains a negation operator (!).
		return $should_negate_value ? ! $current : $current;
	}

	/**
	 * Parse the directive name to extract the following parts:
	 * - Prefix: The main directive name without &quot;data-wp-&quot;. It cannot begin with a hyphen.
	 * - Suffix: An optional suffix used during directive processing, extracted after the first double hyphen &quot;--&quot;.
	 * - Unique ID: An optional unique identifier, extracted after the first triple hyphen &quot;---&quot;.
	 *
	 * This function has an equivalent version for the client side.
	 * See `parseDirectiveName` in https://github.com/WordPress/gutenberg/blob/trunk/packages/interactivity/src/vdom.ts:
	 *
	 * An empty suffix or unique ID is normalized to null, but the string &quot;0&quot; is preserved. The
	 * client&#039;s `|| null` discards only the empty string, since every non-empty string is truthy in
	 * JavaScript. Do not use empty() for these checks: it would discard &quot;0&quot; and diverge from the
	 * client.
	 *
	 * @see Tests_Interactivity_API_WpInteractivityAPI::test_parse_directive_name() for examples in the test inputs.
	 *
	 * @since 6.9.0
	 *
	 * @param string $directive_name The directive attribute name.
	 * @return array|null An array containing the directive prefix, optional suffix, and optional unique ID, or null if the directive name cannot be parsed.
	 * @phpstan-return array{
	 *     prefix: non-empty-string,
	 *     suffix: non-empty-string|null,
	 *     unique_id: non-empty-string|null,
	 * }|null
	 */
	private function parse_directive_name( string $directive_name ): ?array {
		// Remove the first 8 characters (assumes &quot;data-wp-&quot; prefix)
		$name = (string) substr( $directive_name, 8 );

		// Ensure the name only contains valid characters (anything a-z, A-Z, 0-9, -, or _).
		if ( 1 !== preg_match( &#039;/^[a-zA-Z0-9\-_]+$/&#039;, $name ) ) {
			return null;
		}

		// Find the first occurrence of &#039;--&#039; to separate the prefix.
		$suffix_index = strpos( $name, &#039;--&#039; );

		/*
		 * A prefix cannot begin with a hyphen, so a name which does is not a directive at all. This
		 * covers both a lone leading hyphen, as in &quot;data-wp--bind&quot;, and a leading double hyphen, as
		 * in &quot;data-wp---foo&quot;, where treating the hyphens as a suffix separator would instead leave
		 * the prefix empty. It also covers &quot;data-wp----unique-id&quot;, where only a unique ID is supplied
		 * without any prefix or suffix.
		 */
		if ( 0 === $suffix_index || &#039;-&#039; === $name[0] ) {
			return null;
		}

		// Without a &#039;--&#039; the whole name is the prefix. (This naturally also means there is no unique ID after &#039;---&#039;.)
		if ( false === $suffix_index ) {
			return array(
				&#039;prefix&#039;    =&gt; $name,
				&#039;suffix&#039;    =&gt; null,
				&#039;unique_id&#039; =&gt; null,
			);
		}

		$prefix    = substr( $name, 0, $suffix_index );
		$remaining = substr( $name, $suffix_index );

		// If remaining starts with &#039;---&#039; but not &#039;----&#039;, it&#039;s a unique_id
		if ( 3 === strspn( $remaining, &#039;-&#039; ) ) {
			$unique_id = (string) substr( $remaining, 3 );
			return array(
				&#039;prefix&#039;    =&gt; $prefix,
				&#039;suffix&#039;    =&gt; null,
				&#039;unique_id&#039; =&gt; &#039;&#039; === $unique_id ? null : $unique_id,
			);
		}

		// Otherwise, remove the first two dashes for a potential suffix
		$suffix = (string) substr( $remaining, 2 );

		// Look for &#039;---&#039; in the suffix for a unique_id
		$unique_id_index = strpos( $suffix, &#039;---&#039; );

		if ( false !== $unique_id_index &amp;&amp; &#039;-&#039; !== ( $suffix[ $unique_id_index + 3 ] ?? &#039;&#039; ) ) {
			$unique_id = (string) substr( $suffix, $unique_id_index + 3 );
			$suffix    = (string) substr( $suffix, 0, $unique_id_index );
			return array(
				&#039;prefix&#039;    =&gt; $prefix,
				&#039;suffix&#039;    =&gt; &#039;&#039; === $suffix ? null : $suffix,
				&#039;unique_id&#039; =&gt; &#039;&#039; === $unique_id ? null : $unique_id,
			);
		}

		return array(
			&#039;prefix&#039;    =&gt; $prefix,
			&#039;suffix&#039;    =&gt; &#039;&#039; === $suffix ? null : $suffix,
			&#039;unique_id&#039; =&gt; null,
		);
	}

	/**
	 * Parses and extracts the namespace and reference path from the given
	 * directive attribute value.
	 *
	 * If the value doesn&#039;t contain an explicit namespace, it returns the
	 * default one. If the value contains a JSON object instead of a reference
	 * path, the function tries to parse it and return the resulting array. If
	 * the value contains strings that represent booleans (&quot;true&quot; and &quot;false&quot;),
	 * numbers (&quot;1&quot; and &quot;1.2&quot;) or &quot;null&quot;, the function also transform them to
	 * regular booleans, numbers and `null`.
	 *
	 * Example:
	 *
	 *     extract_directive_value( &#039;actions.foo&#039;, &#039;myPlugin&#039; )                      =&gt; array( &#039;myPlugin&#039;, &#039;actions.foo&#039; )
	 *     extract_directive_value( &#039;otherPlugin::actions.foo&#039;, &#039;myPlugin&#039; )         =&gt; array( &#039;otherPlugin&#039;, &#039;actions.foo&#039; )
	 *     extract_directive_value( &#039;{ &quot;isOpen&quot;: false }&#039;, &#039;myPlugin&#039; )              =&gt; array( &#039;myPlugin&#039;, array( &#039;isOpen&#039; =&gt; false ) )
	 *     extract_directive_value( &#039;otherPlugin::{ &quot;isOpen&quot;: false }&#039;, &#039;myPlugin&#039; ) =&gt; array( &#039;otherPlugin&#039;, array( &#039;isOpen&#039; =&gt; false ) )
	 *
	 * @since 6.5.0
	 *
	 * @param string|true $directive_value   The directive attribute value. It can be `true` when it&#039;s a boolean
	 *                                       attribute.
	 * @param string|null $default_namespace Optional. The default namespace if none is explicitly defined.
	 * @return array An array containing the namespace in the first item and the JSON, the reference path, or null on the
	 *               second item.
	 * @phpstan-return array{ 0: string|null, 1: mixed }
	 */
	private function extract_directive_value( $directive_value, $default_namespace = null ): array {
		if ( empty( $directive_value ) || is_bool( $directive_value ) ) {
			return array( $default_namespace, null );
		}

		// Replaces the value and namespace if there is a namespace in the value.
		if ( 1 === preg_match( &#039;/^([\w\-_\/]+)::./&#039;, $directive_value ) ) {
			list($default_namespace, $directive_value) = explode( &#039;::&#039;, $directive_value, 2 );
		}

		/*
		 * Tries to decode the value as a JSON object. If it fails and the value
		 * isn&#039;t `null`, it returns the value as it is. Otherwise, it returns the
		 * decoded JSON or null for the string `null`.
		 */
		$decoded_json = json_decode( $directive_value, true );
		if ( null !== $decoded_json || &#039;null&#039; === $directive_value ) {
			$directive_value = $decoded_json;
		}

		return array( $default_namespace, $directive_value );
	}

	/**
	 * Parse the HTML element and get all the valid directives with the given prefix.
	 *
	 * @since 6.9.0
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p      The directives processor instance.
	 * @param string                                    $prefix The directive prefix to filter by.
	 * @return array An array of entries containing the directive namespace, value, suffix, and unique ID.
	 * @phpstan-return list&lt;array{
	 *     namespace: string|null,
	 *     value: mixed,
	 *     suffix: string|null,
	 *     unique_id: string|null,
	 * }&gt;
	 */
	private function get_directive_entries( WP_Interactivity_API_Directives_Processor $p, string $prefix ): array {
		$directive_attributes = $p-&gt;get_attribute_names_with_prefix( &#039;data-wp-&#039; . $prefix );
		if ( null === $directive_attributes ) {
			return array();
		}

		$entries = array();
		foreach ( $directive_attributes as $attribute_name ) {
			$parsed_directive = $this-&gt;parse_directive_name( $attribute_name );
			if ( null === $parsed_directive ) {
				continue;
			}

			[ &#039;prefix&#039; =&gt; $attr_prefix, &#039;suffix&#039; =&gt; $suffix, &#039;unique_id&#039; =&gt; $unique_id ] = $parsed_directive;
			// Ensure it is the desired directive.
			if ( $prefix !== $attr_prefix ) {
				continue;
			}
			$attribute_value = $p-&gt;get_attribute( $attribute_name );
			if ( null === $attribute_value ) {
				continue;
			}
			/*
			 * The namespace stack can hold false, which data_wp_interactive_processor() pushes for a
			 * `data-wp-interactive` whose namespace is invalid and which has no enclosing one to inherit. Only a
			 * string names a store, so anything else counts as no default namespace at all.
			 */
			$default_namespace = array_last( $this-&gt;namespace_stack ?? array() );
			if ( ! is_string( $default_namespace ) ) {
				$default_namespace = null;
			}

			list( $namespace, $value ) = $this-&gt;extract_directive_value( $attribute_value, $default_namespace );
			$entries[]                 = array(
				&#039;namespace&#039; =&gt; $namespace,
				&#039;value&#039;     =&gt; $value,
				&#039;suffix&#039;    =&gt; $suffix,
				&#039;unique_id&#039; =&gt; $unique_id,
			);
		}
		// Sort directive entries to ensure stable ordering with the client.
		// Put nulls first, then sort by suffix and finally by uniqueIds.
		usort(
			$entries,
			function ( $a, $b ) {
				$a_suffix = $a[&#039;suffix&#039;] ?? &#039;&#039;;
				$b_suffix = $b[&#039;suffix&#039;] ?? &#039;&#039;;
				if ( $a_suffix !== $b_suffix ) {
					return $a_suffix &lt;=&gt; $b_suffix;
				}
				$a_id = $a[&#039;unique_id&#039;] ?? &#039;&#039;;
				$b_id = $b[&#039;unique_id&#039;] ?? &#039;&#039;;
				return $a_id &lt;=&gt; $b_id;
			}
		);
		return $entries;
	}

	/**
	 * Transforms a kebab-case string to camelCase.
	 *
	 * @since 6.5.0
	 *
	 * @param string $str The kebab-case string to transform to camelCase.
	 * @return string The transformed camelCase string.
	 */
	private function kebab_to_camel_case( string $str ): string {
		return lcfirst(
			preg_replace_callback(
				&#039;/(-)([a-z])/&#039;,
				function ( $matches ) {
					return strtoupper( $matches[2] );
				},
				strtolower( rtrim( $str, &#039;-&#039; ) )
			)
		);
	}

	/**
	 * Processes the `data-wp-interactive` directive.
	 *
	 * It adds the default store namespace defined in the directive value to the
	 * stack so that it&#039;s available for the nested interactivity elements.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p    The directives processor instance.
	 * @param string                                    $mode Whether the processing is entering or exiting the tag.
	 */
	private function data_wp_interactive_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
		// When exiting tags, it removes the last namespace from the stack.
		if ( &#039;exit&#039; === $mode ) {
			array_pop( $this-&gt;namespace_stack );
			return;
		}

		// Tries to decode the `data-wp-interactive` attribute value.
		$attribute_value = $p-&gt;get_attribute( &#039;data-wp-interactive&#039; );

		/*
		 * Pushes the newly defined namespace or the current one if the
		 * `data-wp-interactive` definition was invalid or does not contain a
		 * namespace. It does so because the function pops out the current namespace
		 * from the stack whenever it finds a `data-wp-interactive`&#039;s closing tag,
		 * independently of whether the previous `data-wp-interactive` definition
		 * contained a valid namespace.
		 */
		$new_namespace = null;
		if ( is_string( $attribute_value ) &amp;&amp; ! empty( $attribute_value ) ) {
			$decoded_json = json_decode( $attribute_value, true );
			if ( is_array( $decoded_json ) ) {
				$new_namespace = $decoded_json[&#039;namespace&#039;] ?? null;
			} else {
				$new_namespace = $attribute_value;
			}
		}
		$this-&gt;namespace_stack[] = ( $new_namespace &amp;&amp; 1 === preg_match( &#039;/^([\w\-_\/]+)/&#039;, $new_namespace ) )
			? $new_namespace
			: end( $this-&gt;namespace_stack );
	}

	/**
	 * Processes the `data-wp-context` directive.
	 *
	 * It adds the context defined in the directive value to the stack so that
	 * it&#039;s available for the nested interactivity elements.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
	 * @param string                                    $mode            Whether the processing is entering or exiting the tag.
	 */
	private function data_wp_context_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
		// When exiting tags, it removes the last context from the stack.
		if ( &#039;exit&#039; === $mode ) {
			array_pop( $this-&gt;context_stack );
			return;
		}

		$entries = $this-&gt;get_directive_entries( $p, &#039;context&#039; );
		$context = end( $this-&gt;context_stack ) !== false ? end( $this-&gt;context_stack ) : array();
		foreach ( $entries as $entry ) {
			if ( null !== $entry[&#039;suffix&#039;] ) {
				continue;
			}

			/*
			 * A context with no namespace has nothing to be stored under, so the inherited context is left as it
			 * is. Using the namespace as an array key regardless would coerce null to an empty string, which PHP
			 * 8.5 deprecates, and would store the context where no reference can address it anyway.
			 */
			if ( null === $entry[&#039;namespace&#039;] ) {
				continue;
			}

			$context = array_replace_recursive(
				$context,
				array( $entry[&#039;namespace&#039;] =&gt; is_array( $entry[&#039;value&#039;] ) ? $entry[&#039;value&#039;] : array() )
			);
		}
		$this-&gt;context_stack[] = $context;
	}

	/**
	 * Processes the `data-wp-bind` directive.
	 *
	 * It updates or removes the bound attributes based on the evaluation of its
	 * associated reference.
	 *
	 * @since 6.5.0
	 * @since 7.1.0 An object is resolved to whatever it serializes to for the client, a number is formatted by the
	 *              JSON encoder, and a value which cannot be sent to the client is rejected rather than passed to
	 *              WP_HTML_Tag_Processor::set_attribute().
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p    The directives processor instance.
	 * @param string                                    $mode Whether the processing is entering or exiting the tag.
	 */
	private function data_wp_bind_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ): void {
		if ( &#039;enter&#039; === $mode ) {
			$entries = $this-&gt;get_directive_entries( $p, &#039;bind&#039; );
			foreach ( $entries as $entry ) {
				if ( empty( $entry[&#039;suffix&#039;] ) || null !== $entry[&#039;unique_id&#039;] ) {
					continue;
				}

				// Skip if the suffix is an event handler.
				if ( str_starts_with( $entry[&#039;suffix&#039;], &#039;on&#039; ) ) {
					_doing_it_wrong(
						__METHOD__,
						sprintf(
							/* translators: %s: The directive, e.g. data-wp-on--click. */
							__( &#039;Binding event handler attributes is not supported. Please use &quot;%s&quot; instead.&#039; ),
							esc_attr( &#039;data-wp-on--&#039; . substr( $entry[&#039;suffix&#039;], 2 ) )
						),
						&#039;6.9.2&#039;
					);
					continue;
				}

				$result = $this-&gt;evaluate( $entry );

				/*
				 * An object is resolved to whatever it serializes to. When the reference points to a value stored
				 * in state or context, that is the value the client receives for it when the store is hydrated.
				 * A derived state closure is never serialized, so there the client value comes from the derived
				 * state&#039;s client-side implementation instead; the resolution is still applied so that both origins
				 * behave the same. Round-tripping through the JSON encoder rather than calling
				 * JsonSerializable::jsonSerialize() directly keeps this resolution identical to the client&#039;s,
				 * including for an object which serializes to another serializable object. When the encoding fails
				 * the object is left in place, to be reported as a usage error below. Note that it rarely does
				 * fail: wp_json_encode() retries through _wp_json_sanity_check(), which rebuilds the object from
				 * its public properties and so ignores jsonSerialize() altogether. An object whose serialized form
				 * JSON cannot represent therefore resolves to whatever that rebuild encodes to, which is what the
				 * client is sent for it as well.
				 *
				 * A throwing JsonSerializable::jsonSerialize() is caught for the same reason the value is checked
				 * at all: a binding must not be able to abort the render. An exception escaping here would leave
				 * `$context_stack` and `$namespace_stack` unrestored for every later `process_directives()` call
				 * on this instance, so the object is treated as one which failed to encode.
				 */
				if ( is_object( $result ) ) {
					try {
						$encoded = wp_json_encode( $result );
					} catch ( Throwable $e ) {
						$encoded = false;
					}
					if ( false !== $encoded ) {
						$result = json_decode( $encoded );
					}
				}

				/*
				 * Only a value which can be sent to the client may be stored in an attribute value. Strings and
				 * booleans are passed in as-is, numbers are formatted, and everything else is rejected as a usage
				 * error.
				 *
				 * An object which does not serialize to a scalar is rejected even when it defines `__toString()`,
				 * which PHP would otherwise coerce for the string parameters of the escaping functions. Its string
				 * representation is not what the client evaluates this reference to, whether that is the form
				 * serialized into the store or the return value of a derived state&#039;s client-side implementation,
				 * so the two could disagree once the directive is evaluated during hydration.
				 */
				if ( null !== $result ) {
					if ( ! is_scalar( $result ) ) {
						_doing_it_wrong(
							__METHOD__,
							sprintf(
								/* translators: %s: The attribute name. */
								__( &#039;Attempted to bind a non-scalar value to the &quot;%s&quot; attribute. Ensure the state/context property or the derived state closure resolves to a string, number, or boolean.&#039; ),
								esc_html( $entry[&#039;suffix&#039;] )
							),
							&#039;7.1.0&#039;
						);
						$result = null;
					} elseif ( is_int( $result ) || is_float( $result ) ) {
						/*
						 * A number is formatted by the JSON encoder rather than cast to string, so that the
						 * attribute value matches the number the client receives for this same reference. Casting
						 * a float is locale-dependent before PHP 8.0, and rounds to `precision` rather than to the
						 * encoder&#039;s `serialize_precision`.
						 *
						 * This closes the cases which differ in practice, not every one. A float written in
						 * exponent notation still disagrees, since PHP encodes 1e25 as `1.0e+25` where JavaScript
						 * renders it as `1e+25`, as does negative zero, and an integer above the range JavaScript
						 * can represent exactly is rounded once it reaches the client. Casting diverged on all
						 * three as well, so none is a regression.
						 */
						$encoded = wp_json_encode( $result );
						if ( JSON_ERROR_INF_OR_NAN === json_last_error() ) {
							/*
							 * The encoder only rejects INF and NAN, of which JSON can represent neither. When such
							 * a value is stored in state, the store itself also fails to encode in its entirety,
							 * and the client is sent an empty script tag in place of all of its state; only
							 * removing the value from the state resolves that. A derived state closure returning
							 * one never reaches the store, so there only the binding itself is affected.
							 */
							_doing_it_wrong(
								__METHOD__,
								sprintf(
									/* translators: %s: The attribute name. */
									__( &#039;Attempted to bind a non-finite number to the &quot;%s&quot; attribute. Ensure the state/context property or the derived state closure resolves to a finite number or a string.&#039; ),
									esc_html( $entry[&#039;suffix&#039;] )
								),
								&#039;7.1.0&#039;
							);
							$result = null;
						} else {
							$result = $encoded;
						}
					}
				}

				if (
					null !== $result &amp;&amp;
					(
						false !== $result ||
						( strlen( $entry[&#039;suffix&#039;] ) &gt; 5 &amp;&amp; &#039;-&#039; === $entry[&#039;suffix&#039;][4] )
					)
				) {
					/*
					 * If the result of the evaluation is a boolean and the attribute is
					 * `aria-` or `data-, convert it to a string &quot;true&quot; or &quot;false&quot;. It
					 * follows the exact same logic as Preact because it needs to
					 * replicate what Preact will later do in the client:
					 * https://github.com/preactjs/preact/blob/ea49f7a0f9d1ff2c98c0bdd66aa0cbc583055246/src/diff/props.js#L131C24-L136
					 */
					if (
						is_bool( $result ) &amp;&amp;
						( strlen( $entry[&#039;suffix&#039;] ) &gt; 5 &amp;&amp; &#039;-&#039; === $entry[&#039;suffix&#039;][4] )
					) {
						$result = $result ? &#039;true&#039; : &#039;false&#039;;
					}
					$p-&gt;set_attribute( $entry[&#039;suffix&#039;], $result );
				} else {
					$p-&gt;remove_attribute( $entry[&#039;suffix&#039;] );
				}
			}
		}
	}

	/**
	 * Processes the `data-wp-class` directive.
	 *
	 * It adds or removes CSS classes in the current HTML element based on the
	 * evaluation of its associated references.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
	 * @param string                                    $mode            Whether the processing is entering or exiting the tag.
	 */
	private function data_wp_class_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
		if ( &#039;enter&#039; === $mode ) {
			$entries = $this-&gt;get_directive_entries( $p, &#039;class&#039; );
			foreach ( $entries as $entry ) {
				if ( empty( $entry[&#039;suffix&#039;] ) ) {
					continue;
				}
				$class_name = isset( $entry[&#039;unique_id&#039;] ) &amp;&amp; $entry[&#039;unique_id&#039;]
					? &quot;{$entry[&#039;suffix&#039;]}---{$entry[&#039;unique_id&#039;]}&quot;
					: $entry[&#039;suffix&#039;];

				if ( empty( $class_name ) ) {
					return;
				}

				$result = $this-&gt;evaluate( $entry );

				if ( $result ) {
					$p-&gt;add_class( $class_name );
				} else {
					$p-&gt;remove_class( $class_name );
				}
			}
		}
	}

	/**
	 * Processes the `data-wp-style` directive.
	 *
	 * It updates the style attribute value of the current HTML element based on
	 * the evaluation of its associated references.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
	 * @param string                                    $mode            Whether the processing is entering or exiting the tag.
	 */
	private function data_wp_style_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
		if ( &#039;enter&#039; === $mode ) {
			$entries = $this-&gt;get_directive_entries( $p, &#039;style&#039; );
			foreach ( $entries as $entry ) {
				$style_property = $entry[&#039;suffix&#039;];
				if ( empty( $style_property ) || null !== $entry[&#039;unique_id&#039;] ) {
					continue;
				}

				$style_property_value  = $this-&gt;evaluate( $entry );
				$style_attribute_value = $p-&gt;get_attribute( &#039;style&#039; );
				$style_attribute_value = ( $style_attribute_value &amp;&amp; ! is_bool( $style_attribute_value ) ) ? $style_attribute_value : &#039;&#039;;

				/*
				 * Checks first if the style property is not falsy and the style
				 * attribute value is not empty because if it is, it doesn&#039;t need to
				 * update the attribute value.
				 */
				if ( $style_property_value || $style_attribute_value ) {
					$style_attribute_value = $this-&gt;merge_style_property( $style_attribute_value, $style_property, $style_property_value );
					/*
					 * If the style attribute value is not empty, it sets it. Otherwise,
					 * it removes it.
					 */
					if ( ! empty( $style_attribute_value ) ) {
						$p-&gt;set_attribute( &#039;style&#039;, $style_attribute_value );
					} else {
						$p-&gt;remove_attribute( &#039;style&#039; );
					}
				}
			}
		}
	}

	/**
	 * Merges an individual style property in the `style` attribute of an HTML
	 * element, updating or removing the property when necessary.
	 *
	 * If a property is modified, the old one is removed and the new one is added
	 * at the end of the list.
	 *
	 * @since 6.5.0
	 *
	 * Example:
	 *
	 *     merge_style_property( &#039;color:green;&#039;, &#039;color&#039;, &#039;red&#039; )      =&gt; &#039;color:red;&#039;
	 *     merge_style_property( &#039;background:green;&#039;, &#039;color&#039;, &#039;red&#039; ) =&gt; &#039;background:green;color:red;&#039;
	 *     merge_style_property( &#039;color:green;&#039;, &#039;color&#039;, null )       =&gt; &#039;&#039;
	 *
	 * @param string            $style_attribute_value The current style attribute value.
	 * @param string            $style_property_name   The style property name to set.
	 * @param string|false|null $style_property_value  The value to set for the style property. With false, null or an
	 *                                                 empty string, it removes the style property.
	 * @return string The new style attribute value after the specified property has been added, updated or removed.
	 */
	private function merge_style_property( string $style_attribute_value, string $style_property_name, $style_property_value ): string {
		$style_assignments    = explode( &#039;;&#039;, $style_attribute_value );
		$result               = array();
		$style_property_value = ! empty( $style_property_value ) ? rtrim( trim( $style_property_value ), &#039;;&#039; ) : null;
		$new_style_property   = $style_property_value ? $style_property_name . &#039;:&#039; . $style_property_value . &#039;;&#039; : &#039;&#039;;

		// Generates an array with all the properties but the modified one.
		foreach ( $style_assignments as $style_assignment ) {
			if ( empty( trim( $style_assignment ) ) ) {
				continue;
			}
			list( $name, $value ) = explode( &#039;:&#039;, $style_assignment );
			if ( trim( $name ) !== $style_property_name ) {
				$result[] = trim( $name ) . &#039;:&#039; . trim( $value ) . &#039;;&#039;;
			}
		}

		// Adds the new/modified property at the end of the list.
		$result[] = $new_style_property;

		return implode( &#039;&#039;, $result );
	}

	/**
	 * Processes the `data-wp-text` directive.
	 *
	 * It updates the inner content of the current HTML element based on the
	 * evaluation of its associated reference.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
	 * @param string                                    $mode            Whether the processing is entering or exiting the tag.
	 */
	private function data_wp_text_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
		if ( &#039;enter&#039; === $mode ) {
			$entries     = $this-&gt;get_directive_entries( $p, &#039;text&#039; );
			$valid_entry = null;
			// Get the first valid `data-wp-text` entry without suffix or unique ID.
			foreach ( $entries as $entry ) {
				if ( null === $entry[&#039;suffix&#039;] &amp;&amp; null === $entry[&#039;unique_id&#039;] &amp;&amp; ! empty( $entry[&#039;value&#039;] ) ) {
					$valid_entry = $entry;
					break;
				}
			}
			if ( null === $valid_entry ) {
				return;
			}
			$result = $this-&gt;evaluate( $valid_entry );

			/*
			 * Follows the same logic as Preact in the client and only changes the
			 * content if the value is a string or a number. Otherwise, it removes the
			 * content.
			 */
			if ( is_string( $result ) || is_numeric( $result ) ) {
				$p-&gt;set_content_between_balanced_tags( esc_html( $result ) );
			} else {
				$p-&gt;set_content_between_balanced_tags( &#039;&#039; );
			}
		}
	}

	/**
	 * Returns the CSS styles for animating the top loading bar in the router.
	 *
	 * @since 6.5.0
	 *
	 * @return string The CSS styles for the router&#039;s top loading bar animation.
	 */
	private function get_router_animation_styles(): string {
		return &lt;&lt;&lt;CSS
			.wp-interactivity-router-loading-bar {
				position: fixed;
				top: 0;
				left: 0;
				margin: 0;
				padding: 0;
				width: 100vw;
				max-width: 100vw !important;
				height: 4px;
				background-color: #000;
				opacity: 0
			}
			.wp-interactivity-router-loading-bar.start-animation {
				animation: wp-interactivity-router-loading-bar-start-animation 30s cubic-bezier(0.03, 0.5, 0, 1) forwards
			}
			.wp-interactivity-router-loading-bar.finish-animation {
				animation: wp-interactivity-router-loading-bar-finish-animation 300ms ease-in
			}
			@keyframes wp-interactivity-router-loading-bar-start-animation {
				0% { transform: scaleX(0); transform-origin: 0 0; opacity: 1 }
				100% { transform: scaleX(1); transform-origin: 0 0; opacity: 1 }
			}
			@keyframes wp-interactivity-router-loading-bar-finish-animation {
				0% { opacity: 1 }
				50% { opacity: 1 }
				100% { opacity: 0 }
			}
CSS;
	}

	/**
	 * Deprecated.
	 *
	 * @since 6.5.0
	 * @deprecated 6.7.0 Use {@see WP_Interactivity_API::print_router_markup} instead.
	 */
	public function print_router_loading_and_screen_reader_markup() {
		_deprecated_function( __METHOD__, &#039;6.7.0&#039;, &#039;WP_Interactivity_API::print_router_markup&#039; );

		// Call the new method.
		$this-&gt;print_router_markup();
	}

	/**
	 * Outputs markup for the @wordpress/interactivity-router script module.
	 *
	 * This method prints a div element representing a loading bar visible during
	 * navigation.
	 *
	 * @since 6.7.0
	 */
	public function print_router_markup() {
		echo &lt;&lt;&lt;HTML
			&lt;div
				class=&quot;wp-interactivity-router-loading-bar&quot;
				data-wp-interactive=&quot;core/router/private&quot;
				data-wp-class--start-animation=&quot;state.navigation.hasStarted&quot;
				data-wp-class--finish-animation=&quot;state.navigation.hasFinished&quot;
			&gt;&lt;/div&gt;
HTML;
	}

	/**
	 * Processes the `data-wp-router-region` directive.
	 *
	 * It renders in the footer a set of HTML elements to notify users about
	 * client-side navigations. More concretely, the elements added are 1) a
	 * top loading bar to visually inform that a navigation is in progress
	 * and 2) an `aria-live` region for accessible navigation announcements.
	 *
	 * @since 6.5.0
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
	 * @param string                                    $mode            Whether the processing is entering or exiting the tag.
	 */
	private function data_wp_router_region_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
		if ( &#039;enter&#039; === $mode &amp;&amp; ! $this-&gt;has_processed_router_region ) {
			$this-&gt;has_processed_router_region = true;

			// Initializes the `state.url` property from the server.
			$this-&gt;state(
				&#039;core/router&#039;,
				array(
					&#039;url&#039; =&gt; get_self_link(),
				)
			);

			// Enqueues as an inline style.
			wp_register_style( &#039;wp-interactivity-router-animations&#039;, false );
			wp_add_inline_style( &#039;wp-interactivity-router-animations&#039;, $this-&gt;get_router_animation_styles() );
			wp_enqueue_style( &#039;wp-interactivity-router-animations&#039; );

			// Adds the necessary markup to the footer.
			add_action( &#039;wp_footer&#039;, array( $this, &#039;print_router_markup&#039; ) );
		}
	}

	/**
	 * Processes the `data-wp-each` directive.
	 *
	 * This directive gets an array passed as reference and iterates over it
	 * generating new content for each item based on the inner markup of the
	 * `template` tag.
	 *
	 * @since 6.5.0
	 * @since 6.9.0 Include the list path in the rendered `data-wp-each-child` directives.
	 *
	 * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
	 * @param string                                    $mode            Whether the processing is entering or exiting the tag.
	 * @param array                                     $tag_stack       The reference to the tag stack.
	 */
	private function data_wp_each_processor( WP_Interactivity_API_Directives_Processor $p, string $mode, array &amp;$tag_stack ) {
		if ( &#039;enter&#039; === $mode &amp;&amp; &#039;TEMPLATE&#039; === $p-&gt;get_tag() ) {
			$entries = $this-&gt;get_directive_entries( $p, &#039;each&#039; );
			if ( count( $entries ) &gt; 1 || empty( $entries ) ) {
				// There should be only one `data-wp-each` directive per template tag.
				return;
			}
			$entry = $entries[0];
			if ( null !== $entry[&#039;unique_id&#039;] ) {
				return;
			}
			$item_name = isset( $entry[&#039;suffix&#039;] ) ? $this-&gt;kebab_to_camel_case( $entry[&#039;suffix&#039;] ) : &#039;item&#039;;
			$result    = $this-&gt;evaluate( $entry );

			// Gets the content between the template tags and leaves the cursor in the closer tag.
			$inner_content = $p-&gt;get_content_between_balanced_template_tags();

			// Checks if there is a manual server-side directive processing.
			$template_end = &#039;data-wp-each: template end&#039;;
			$p-&gt;set_bookmark( $template_end );
			$p-&gt;next_tag();
			$manual_sdp = $p-&gt;get_attribute( &#039;data-wp-each-child&#039; );
			$p-&gt;seek( $template_end ); // Rewinds to the template closer tag.
			$p-&gt;release_bookmark( $template_end );

			/*
			 * It doesn&#039;t process in these situations:
			 * - Manual server-side directive processing.
			 * - Empty or non-array values.
			 * - Associative arrays because those are deserialized as objects in JS.
			 * - Templates that contain top-level texts because those texts can&#039;t be
			 *   identified and removed in the client.
			 */
			if (
				$manual_sdp ||
				empty( $result ) ||
				! is_array( $result ) ||
				! array_is_list( $result ) ||
				! str_starts_with( trim( $inner_content ), &#039;&lt;&#039; ) ||
				! str_ends_with( trim( $inner_content ), &#039;&gt;&#039; )
			) {
				array_pop( $tag_stack );
				return;
			}

			// Processes the inner content for each item of the array.
			$processed_content = &#039;&#039;;
			foreach ( $result as $item ) {
				// Creates a new context that includes the current item of the array.
				$this-&gt;context_stack[] = array_replace_recursive(
					end( $this-&gt;context_stack ) !== false ? end( $this-&gt;context_stack ) : array(),
					array( $entry[&#039;namespace&#039;] =&gt; array( $item_name =&gt; $item ) )
				);

				// Processes the inner content with the new context.
				$processed_item = $this-&gt;_process_directives( $inner_content );

				if ( null === $processed_item ) {
					// If the HTML is unbalanced, stop processing it.
					array_pop( $this-&gt;context_stack );
					return;
				}

				/*
				 * Adds the `data-wp-each-child` directive to each top-level tag
				 * rendered by this `data-wp-each` directive. The value is the
				 * `data-wp-each` directive&#039;s namespace and path.
				 *
				 * Nested `data-wp-each` directives could render
				 * `data-wp-each-child` elements at the top level as well, and
				 * they should be overwritten.
				 *
				 * @since 6.9.0
				 */
				$i = new WP_Interactivity_API_Directives_Processor( $processed_item );
				while ( $i-&gt;next_tag() ) {
					$i-&gt;set_attribute( &#039;data-wp-each-child&#039;, $entry[&#039;namespace&#039;] . &#039;::&#039; . $entry[&#039;value&#039;] );
					$i-&gt;next_balanced_tag_closer_tag();
				}
				$processed_content .= $i-&gt;get_updated_html();

				// Removes the current context from the stack.
				array_pop( $this-&gt;context_stack );
			}

			// Appends the processed content after the tag closer of the template.
			$p-&gt;append_content_after_template_tag_closer( $processed_content );

			// Pops the last tag because it skipped the closing tag of the template tag.
			array_pop( $tag_stack );
		}
	}
}
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