Explore different ways of providing Bit renderers.

src/wp-includes/bits.php

@@ -8,6 +8,8 @@
  * @since      {WP_VERSION}
  */
 
+declare( strict_types=1 );
+
 /**
  * Hello Dolly Bit Rendering function.
  *
@@ -48,3 +50,76 @@ function core_bit_hello_dolly( string $name, string $output_type, ?array $attrib
 	}
 }
 
+class WP_Hello_Dolly_Bit extends BitProvider {
+	/**
+	 * @inheritDoc
+	 */
+	public function handle_plaintext( string $bit_name, ?array $attributes ): string {
+		return self::get_random_vocalist();
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function handle_richtext( string $bit_name, ?array $attributes ): WP_HTML_Template {
+		$name = self::get_random_vocalist();
+
+		return new WP_HTML_Template(
+			'<span data-vocalist="</%name>"></%name></span>',
+			array( 'name' => $name )
+		);
+	}
+
+	/**
+	 * Returns the name of a random Jazz vocalist.
+	 *
+	 * @return string
+	 */
+	private function get_random_vocalist(): string {
+		static $vocalists = array(
+			'Julie Dahle Aagård',
+			'Mindi Abair',
+			'Lorez Alexandria',
+			'Karrin Allyson',
+			'Michelle Amato',
+			'Ernestine Anderson',
+			'Ivie Anderson',
+		);
+
+		return $vocalists[ wp_rand( 0, count( $vocalists ) - 1 ) ];
+	}
+}
+
+abstract class BitProvider {
+	/**
+	 * Performs initialize of Bit Provider during WordPress bootup.
+	 */
+	public function register(): void {
+		// This is optional.
+	};
+
+	/**
+	 * Called to source content in plaintext contexts. For example, when a
+	 * Bit is found within an HTML attribute, or inside a `TITLE` element.
+	 *
+	 * @see WP_HTML_Template
+	 *
+	 * @param string     $bit_name   Full name with namespace of matched Bit, e.g. "core/post-author".
+	 * @param array|null $attributes Configured attributes found on Bit, if found, otherwise `null`.
+	 *
+	 * @return string Plaintext value for provided content.
+	 */
+	abstract public function handle_plaintext( string $bit_name, ?array $attributes ): string;
+
+	/**
+	 * Called to source content in Rich Text (HTML Markup) contexts. For example,
+	 * when a Bit is found within the inner content of an HTML tag.
+	 *
+	 * @see WP_HTML_Template
+	 *
+	 * @param string     $bit_name   Full name with namespace of matched Bit, e.g. "core/post-author".
+	 * @param array|null $attributes Configured attributes found on Bit, if found, otherwise `null`.
+	 * @return WP_HTML_Template HTML template for provided content: a string or array.
+	 */
+	abstract public function handle_richtext( string $bit_name, ?array $attributes ): WP_HTML_Template;
+}

src/wp-includes/html-api/class-wp-html-template.php

@@ -0,0 +1,48 @@
+<?php
+
+declare( strict_types=1 );
+
+class WP_HTML_Template {
+	/**
+	 * HTML Template indicating where to mix a static HTML template
+	 * and placeholders for dynamic values.
+	 *
+	 * @var string
+	 */
+	public $template;
+
+	/**
+	 * Stores data necessary to render a template, if any required.
+	 *
+	 * @var array|null
+	 */
+	public $data;
+
+	/**
+	 * Constructor function.
+	 *
+	 * Example:
+	 *
+	 *     // No placeholders are required, only a template string.
+	 *     new WP_HTML_Template( '<p>Hello, World!</p>' );
+	 *
+	 *     // Placeholders for simple substitution.
+	 *     new WP_HTML_Template( '<p>Hello, </%name>!</p>', array( 'name' => $name ) );
+	 *
+	 *     // Spread-operator for sets of attributes.
+	 *     new WP_HTML_Template(
+	 *         '<button ...interactivity_args>Click me!</button>',
+	 *         array(
+	 *             'data-wp-text="context.buttonLabel"',
+	 *             'data-wp-click="actions.clickButton",
+	 *         )
+	 *     );
+	 *
+	 * @param string     $template Static HTML template, possibly including placeholders.
+	 * @param array|null $data     Optional. Data provided for placeholders, if any.
+	 */
+	public function __construct( string $template, array $data = null ) {
+		$this->template = $template;
+		$this->data     = $data;
+	}
+}

src/wp-settings.php

@@ -262,6 +262,7 @@
 require ABSPATH . WPINC . '/html-api/class-wp-html-stack-event.php';
 require ABSPATH . WPINC . '/html-api/class-wp-html-processor-state.php';
 require ABSPATH . WPINC . '/html-api/class-wp-html-processor.php';
+require ABSPATH . WPINC . '/html-api/class-wp-html-template.php';
 require ABSPATH . WPINC . '/html-api/class-wp-bits.php';
 require ABSPATH . WPINC . '/class-wp-http.php';
 require ABSPATH . WPINC . '/class-wp-http-streams.php';