Variable scope issue in PHP

Question

So I've got a class on which I've added different methods to customize my Wordpress theme. One of the methods is called limitExcerptToWords, and what it does is limiting the length of the excerpt returned by WP.

The way you do this in WP is by adding a function to a hook, the function can be expressed as a string (name of the function), or like in my case, as an anonymous function. The value returned by this function will be the length of the excerpt.

My code looks like this:

class XX {
   /* ... */
   function limitExcerptToWords($numWords) {
       add_filter( 'excerpt_length', function (){
            return $numwords;
        });
   }
   /* ... */
}

Then I would like to invoque that method like: $OBJ->limitExcerptToWords(10);

I'm much more knowledgable in JS, where this code would work jsut fine, but PHP has a different way of dealing with scopes, and as a result the code inside my anonymous function doesn't have $numWords in scope.

I've been reading through the PHP docs but I can't gind a way of getting this to work in an elegant way.

Can you help? :3

Thanks!

Possible duplicate of PHP lambda functions and scope

Ruslan Osmanov
– Ruslan Osmanov

2016-05-06 12:10:15 +00:00
Commented May 6, 2016 at 12:10 — Ruslan Osmanov
– Ruslan Osmanov, Commented May 6, 2016 at 12:10

DarkBee · Accepted Answer · 2016-05-06 12:08:36Z

2

If you want to use it inside the anom function you need to pass it with use

class XX {
   /* ... */
   function limitExcerptToWords($numWords) {
       add_filter( 'excerpt_length', function () use($numWords) {
            return $numwords;
        });
   }
   /* ... */
}

answered May 6, 2016 at 12:08

DarkBee

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1 Comment

Ruben Serrate Over a year ago

As if by magic!! Somehow I missed this when I first read the anonymous functions manual, found it now! (php.net/manual/en/functions.anonymous.php#example-197) Thanks a lot boss!

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