[RESOLVED] Quotation Mark, Single Colon, and Other Operators in phpBB

nn123654

I was looking through the phpBB source code version 3.0.0 and ran into the following code in multiple places. I was wondering what the (int), ?, and : does in the code.

From Lines 155 to 157 from the posting.php file:

$forum_id	= (!empty($post_data['forum_id'])) ? (int) $post_data['forum_id'] : (int) $forum_id;
$topic_id	= (!empty($post_data['topic_id'])) ? (int) $post_data['topic_id'] : (int) $topic_id;
$post_id	= (!empty($post_data['post_id'])) ? (int) $post_data['post_id'] : (int) $post_id;

From Lines 344 to 350 in posting.php:

$post_data['post_edit_locked']	= (isset($post_data['post_edit_locked'])) ? (int) $post_data['post_edit_locked'] : 0;
$post_data['post_subject']		= (in_array($mode, array('quote', 'edit'))) ? $post_data['post_subject'] : ((isset($post_data['topic_title'])) ? $post_data['topic_title'] : '');
$post_data['topic_time_limit']	= (isset($post_data['topic_time_limit'])) ? (($post_data['topic_time_limit']) ? (int) $post_data['topic_time_limit'] / 86400 : (int) $post_data['topic_time_limit']) : 0;
$post_data['poll_length']		= (!empty($post_data['poll_length'])) ? (int) $post_data['poll_length'] / 86400 : 0;
$post_data['poll_start']		= (!empty($post_data['poll_start'])) ? (int) $post_data['poll_start'] : 0;
$post_data['icon_id']			= (!isset($post_data['icon_id']) || in_array($mode, array('quote', 'reply'))) ? 0 : (int) $post_data['icon_id'];
$post_data['poll_options']		= array();

Thanks

bradgrafelman

The B[/B] part is typecasting, or "type juggling" which forces PHP to evaluate the given variable as an integer. It's similar to running the variable through [man]intval/man in this case. For more information on type juggling, see this section in the PHP manual.

As for the "condition ? expression : expression" syntax, see this section in the manual to learn more about the "ternary operator" (essentially a shorthand way of writing an if/else statement).