Improve the WordPress loop

[wpscholar]

Currently, there are a number of ways that the "loop" can be handled in WordPress. Each depends on whether you are using the WP_Query global, a custom WP_Query instance, or an array of posts.

I propose that we add a PHP 5.6+ compatible generator function called wp_loop() that will simplify all of these use cases into a single, more modern approach. See ​https://wpscholar.com/blog/creating-better-wordpress-loop/

[knutsp]

Thank you for the suggestion! Now, that's very interesting.

Just needs testing of every scenario, including performance compared to the classic loop setup.

[mukesh27]

@wpscholar Can you please add doc for global $post variable in the patch trac-48193-wp-loop.diff?

* @global WP_Post $post Global post object.

[ayeshrajans]

This indeed looks interesting! Do you have any use cases in existing core loops so we can benchmark for time/memory?

Speaking from a clean code perspective, using global variables in new function seems a bit off, where we could create a function with proper typing and be more strict, and hand over the responsibility of passing correct \WP_Query instance to the caller. This will make writing tests quite easy too.

In the original patch, there is a line if ( ! is_array( $posts ) ) {. May be we can use is_iterable here? WordPress has a polyfill for this PHP 7.1 function, and this will allow callers to pass Traversable instances too, which the foreach block that proceeds it will happily accept. Because we are talking about using generators over array, I think it's safe to assume the callers would have Traversable objects instead of arrays.

[wpscholar]

Just added some unit tests and made a few changes to the function. It now supports the passing of an iterator, not just an array or query instance. The doc was updated to include an @global for the $post object

Pull request for WordPress trac ticket #48193 (https://core.trac.wordpress.org/ticket/48193)