Title: Filter issue Last modified: April 1, 2020 --- # Filter issue * [TWD](https://wordpress.org/support/users/twd/) * (@twd) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/) * How can I make this code more robust? i.e. so it doesn’t throw an error if the ICL_LANGUAGE_CODE constant doesn’t exist. I have used this code snippet on WPML sites to attach different font-families depending on the language class attached to the tag. * ``` add_filter('body_class', 'append_language_class'); function append_language_class($classes){ $classes[] = ICL_LANGUAGE_CODE; return $classes; } ``` - This topic was modified 6 years, 2 months ago by [Jan Dembowski](https://wordpress.org/support/users/jdembowski/). Viewing 7 replies - 1 through 7 (of 7 total) * [mark l chaves](https://wordpress.org/support/users/mlchaves/) * (@mlchaves) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12611129) * Hi [@twd](https://wordpress.org/support/users/twd/), * Give something like this a try. * ``` define('ICL_LANGUAGE_CODE', 'something'); $classes[] = defined('ICL_LANGUAGE_CODE') ? ICL_LANGUAGE_CODE : false; var_dump($classes); // Dumps 'something' ``` * ``` // define('ICL_LANGUAGE_CODE', 'something'); $classes[] = defined('ICL_LANGUAGE_CODE') ? ICL_LANGUAGE_CODE : false; var_dump($classes); // Dumps false ``` * Thread Starter [TWD](https://wordpress.org/support/users/twd/) * (@twd) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12611200) * I don’t follow. * What about something simple like this?: * ``` add_filter('body_class', 'append_language_class'); function append_language_class($classes){ if(ICL_LANGUAGE_CODE){ $classes[] = ICL_LANGUAGE_CODE; return $classes; } } ``` * [mark l chaves](https://wordpress.org/support/users/mlchaves/) * (@mlchaves) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12611319) * Hi [@twd](https://wordpress.org/support/users/twd/), * Your code would throw a warning or error depending on which PHP version used. * I suggest you run both my examples and your code as a proof to yourself what will work and what won’t. That’s the beauty of coding–like mathematics you can always test your answer 😉 * Thanks! * P.s. Learn more about the `defined` function here [https://www.php.net/manual/en/function.defined.php](https://www.php.net/manual/en/function.defined.php) * Thread Starter [TWD](https://wordpress.org/support/users/twd/) * (@twd) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12611493) * Ah thanks. I’m learning already. Didn’t realize that there is a different way to check for the existence of variables, * `isset()` * compared to constants * `defined()` * looks like I’ve got a lot of study to do. * I’m a bit confused about “something” in your example though. Can you flesh that out a bit? * And why do I need to write the function twice? The two code examples are identical, no? - This reply was modified 6 years, 2 months ago by [TWD](https://wordpress.org/support/users/twd/). - This reply was modified 6 years, 2 months ago by [TWD](https://wordpress.org/support/users/twd/). * Moderator [bcworkz](https://wordpress.org/support/users/bcworkz/) * (@bcworkz) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12613112) * The constant definition in the second is commented out so no definition is made. Thus the output is different. * Do you know about the ternary operator? `boolean ? 'something' : 'another';` It’s equivalent to `if ( boolean ) 'something' else 'another';` except it returns the value where if statements do not. * Thread Starter [TWD](https://wordpress.org/support/users/twd/) * (@twd) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12614805) * [@bcworkz](https://wordpress.org/support/users/bcworkz/) * OK. At least the second snippet makes sense now. * Why is it necessary to include this line? `var_dump($classes); // Dumps false` - This reply was modified 6 years, 2 months ago by [TWD](https://wordpress.org/support/users/twd/). - This reply was modified 6 years, 2 months ago by [TWD](https://wordpress.org/support/users/twd/). * [mark l chaves](https://wordpress.org/support/users/mlchaves/) * (@mlchaves) * [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12614841) * Hi [@twd](https://wordpress.org/support/users/twd/), * I recommend you **run **the code yourself so learn what it’s doing. You can also Duck Duck Go or Google `var_dump` function. * [https://www.php.net/manual/en/function.var-dump.php](https://www.php.net/manual/en/function.var-dump.php) * `var_dump` is useful for testing and debugging! So, it’s necessary for testing and proofing. * Once you prove the code works, you can remove the `var_dump` call. You should really be testing all this code yourself as proof. * Thanks! - This reply was modified 6 years, 2 months ago by [mark l chaves](https://wordpress.org/support/users/mlchaves/). Reason: Clarification Viewing 7 replies - 1 through 7 (of 7 total) The topic ‘Filter issue’ is closed to new replies. ## Tags * [php](https://wordpress.org/support/topic-tag/php/) * In: [Developing with WordPress](https://wordpress.org/support/forum/wp-advanced/) * 7 replies * 3 participants * Last reply from: [mark l chaves](https://wordpress.org/support/users/mlchaves/) * Last activity: [6 years, 2 months ago](https://wordpress.org/support/topic/noobie-php-question/#post-12614841) * Status: not resolved ## Topics ### Topics with no replies ### Non-support topics ### Resolved topics ### Unresolved topics ### All topics