Filter for Block Elements in wpautop()

[luehrsen]

This addresses the need to exclude certain block elements (iframe, img) from wpautop. Using the newly defined filter wpautop_block_elements every plugin dev, theme dev etc. can redefine, modify and enhance the list of block elements.

Exsample for functions.php

function add_block_elements($block_elements){   
        $block_elements[] = "iframe";   
        $block_elements[] = "img";      
        
        return $block_elements;
}
add_filter("wpautop_block_elements", add_block_elements);

Thanks for reviewing! :)

Regards,
Hendrik

Defined preexisting block elements as array, filtered that array, imploded to regex.

Neither iframes nor images are block-level elements. This mangling should not be left to plugins.

As for HTML standards, HTML5 does not any longer differentiate between inline and block, it rather has more categories possible for each element. ​http://dev.w3.org/html5/html4-differences/#content-model

Aside from digging into standards, there should be a standardized way for developers to exclude certain elements from wpautop. Disabling and optionally replacing the function (as it is regularly done) is not a suitable solution.