how to check if a shortcode is used more than one time in the same post

Question

I've written a shortcode plugin. Basically the plugin has the following structure:

PL::setup();

class PL {

public static function setup() {
add_shortcode("myshortcode", array ( __CLASS__,"myshortcode_handler"));
}

public static function myshortcode_handler(
... some variable assignment?
   if (time the shortcode is invoked == 1) {
      ... 
   }
   else {
      ...
   }
... some other code lines
}

}

I need to distinguish the case the shortcode is invoked for the first time or not. I think I have to declare some variable, but I do not know how and where I have to declare it.

Answer 1

In your shortcode callback myshortcode_handler(), use a static variable:

function myshortcode_handler()
{
    static $first_call = TRUE;

    if ( ! $first_call )
    {
        # callback was called earlier …
    }

    # set it to FALSE after you have handled the condition.
    $first_call = FALSE;

    return;
}

Please do not misuse the global namespace for this: avoid constants, global variables and similar workarounds that might lead to unexpected conflicts.

Answer 2

There are a number of ways to do this. One of those ways is to define a constant the first time your callback runs.

if (!defined('myshortcode_check')) {
  // first time code
  define('myshortcode_check',true);
} else {
  // not the first time code
}

Should be fairly simple. That is a global, though, not post specific. This should work fine for single posts displays but may not be the behavior you want on post indexes. If that shortcode runs on any post in the index, it will define the constant.

http://php.net/manual/en/function.defined.php
http://php.net/manual/en/function.define.php