Pass variable from loop to function - php

Question

I've been working with Php for less than 2 months (this is also my first question so please tell me if I'm missing something) and it has been going smooth right up till today. I'm working on a form plugin for Wordpress and currently implementing the code to make the forms saved in the database to connect with a shortcode which includes the ID of the form in the database. The 1st form has an ID of 1 and the shortcode is IForm_1. Pretty simple.
The problem occurs when looping thru all the forms and not being able to pass the $ID value from the loop to the IForm function.
$ID= 0;
$FormID= 0;
settype($ID, "integer");
for ($x = 1; $x <= 300; $x++) {
global $ID;
$ID++;
$ShortCode = "IForm_";
$ShortCode .= $ID;
$FormID = $ID;
add_shortcode( $ShortCode, 'IForm_Array' );
$ShortCode ='';
}
here is the loop which is very simple, when the $ShortCode lines up with the shortcode used on the site it works and the IForm get used as it should.
function IForm(){
global $ID;
//testing_decode();
// Gets the value of baseTest from getDB and puts it in test.
$DBForm = getDB($ID);
$Form = $DBForm;
$Form .= "Works but not really";
return $Form;
}
Here is the function.
Problem is that $ID is always 300 in the function which is the end of the loop. IForm is executed when the $ID in the loop lines up with the shortcode ID on the site/post which tells me the $ID value is indeed correct for some part of the loop. When the ID is indeed correct I would like to pass it to the IForm function to use it to find the right form in the database(MySQL).
Now my question is how would I pass (if that can even be done) the $ID value on the 3rd row of the loop to the 5th row of function. Alternatively would be to force break the loop when it lines up and use the last $ID value to be passed to IForm.

Answer 1

WordPress makes this a little more complicated than it needs to be, because you can't pass additional parameters to a shortcode (afaik).
Before we start, let's understand the 300. The loop in which you add the shortcodes gets executed during an early stage of the page load. The actual call to your shortcode function at a later stage. At that time the global $ID variable will have its final value (300 in your case)
Here are two ways to solve this:
First, you can use closures, and inherit $ID from the parent scope:
for ($x = 1; $x <= 300; $x++) {
$ID++;
$ShortCode = "IForm_";
$ShortCode .= $ID;
$FormID = $ID;
add_shortcode( $ShortCode, function () use ($ID) {
$DBForm = getDB($ID);
$Form = $DBForm;
$Form .= "Works but not really";
return $Form;
} );
$ShortCode ='';
}
You can read more about it in the manual. It also explains the difference between use and global variables.
Second, you can use shortcode attributes. You would not use [Form_1] anymore, but [Form id=1]. Then you can access the id within the array that Wordpress automatically passes to your function.
function IForm($attr){
$ID = intval($attr['id']); // A little sanitation, because $attr could come from a user with low privileges
$DBForm = getDB($ID);
$Form = $DBForm;
$Form .= "Works but not really";
return $Form;
}
A little documentation about this is available here.

Answer 2

Lets see what you did there
$ID= 0;
// Define a variable called ID
for ($x = 1; $x <= 300; $x++) {
global $ID;
// get access to global variable id
$ID++;
// increment local or global counter, undefined behaviour
instead i recommend doing
global $ID;
for ($x = 1; $x <= 300; $x++) {
$ID++;
// Do what you think you have to do
do not pass variables over global variables into functions, instead use parameter
function IForm($id){
//testing_decode();
$DBForm = getDB($id);
$Form = $DBForm;
$Form .= "Works very good";
return $Form;
}
and call the function like
IForm(42); //or
IForm($ID);