What's the problem exactly?

From what I've seen so far, though :

function __construct() {
			$functions_array = array(
			$this->more_jump_link($link)
		);
		return $functions_array;
	}

You put $link in more_jump_link, however you don't pass it in your constructor, and you don't have a set method. $link will then always be null. $link is not linked to any property in your class.

See, in your function, you're passing ($link) in the parameters of the function. However you never do in your class, thus $link is always null in the code.

Also, in the constructor, you are doing this :

function __construct() {
			$functions_array = array(
			$this->more_jump_link($link)
		);
		return $functions_array;

$link at this point is null, since you did not receive it in construct($link). Also, your more_jump_link function is defined as not receiving any parameter :

public function more_jump_link() {
		$offset = strpos($link, '#more-');
		if ($offset) {
			$end = strpos($link, '"',$offset);
		}
		if ($end) {
			$link = substr_replace($link, '', $offset, $end-$offset);
		}
		return $link;
	}

You can see there that jump_link() is not waiting for the $link parameter you are passing in the constructor.


Do something like this and tell me if it work :

class wp_more_jump_class {
	function __construct()
        {
	}

	public function more_jump_link($link) {
		$offset = strpos($link, '#more-');
		if ($offset) {
			$end = strpos($link, '"',$offset);
		}
		if ($end) {
			$link = substr_replace($link, '', $offset, $end-$offset);
		}
		return $link;
	}
  
	public function action_filters ()
{
		add_filter('the_content_more_link', $this->more_jump_link);
	}
}

$call_wp_more_jump = new wp_more_jump_class();
$call_wp_more_jump->more_jump_link($link);

Note : action_filters will crash if you call it. You are trying to access a variable that does not exist.

In and of itself, the function in your original post should be a function, and not a class.

It receives a value, does something simple to it, returns it, and forgets about it. Unless this is just one step in a bigger process, then there is no point in turning it into a class.