WordPress loop generator function, as described at https://wpscholar.com/blog/creating-better-wordpress-loop/

wp-loop.php

<?php

/**
 * Simplifies the WordPress loop.
 *
 * @param WP_Query|WP_Post[] $iterable
 *
 * @return Generator
 */
function wp_loop( $iterable = null ) {

	if ( null === $iterable ) {
		$iterable = $GLOBALS['wp_query'];
	}

	$posts = $iterable;
	if ( is_object( $iterable ) && property_exists( $iterable, 'posts' ) ) {
		$posts = $iterable->posts;
	}

	if ( ! is_array( $posts ) ) {
		throw new \InvalidArgumentException( sprintf( 'Expected an array, received %s instead', gettype( $posts ) ) );
	}

	global $post;

	// Save the global post object so we can restore it later
	$save_post = $post;

	try {

		foreach ( $posts as $post ) {
			setup_postdata( $post );
			yield $post;
		}

	} finally {
		wp_reset_postdata();

		// Restore the global post object
		$post = $save_post;
	}	
}