php how to: save session variable into a static class variable - php

Question

Below code works fine:
<?php session_start();
$_SESSION['color'] = 'blue';
class utilities
{
public static $color;
function display()
{
echo utilities::$color = $_SESSION['color'];
}
}
utilities::display(); ?>
This is what I want but doesn't work:
<?php session_start();
$_SESSION['color'] = 'blue';
class utilities {
public static $color = $_SESSION['color']; //see here
function display()
{
echo utilities::$color;
} } utilities::display(); ?>
I get this error: Parse error: syntax error, unexpected T_VARIABLE in C:\Inetpub\vhosts\morsemfgco.com\httpdocs\secure2\scrap\class.php on line 7
Php doesn't like session variables being stored outside of functions. Why? Is it a syntax problem or what? I don't want to have to instantiate objects because for just calling utility functions and I need a few session variables to be stored globally. I do not want to call a init() function to store the global session variables every time I run a function either. Solutions?

Answer 1

In a class you can use SESSION only in methods...
Actually, if you want to do something in a class, you must code it in a method...
A class is not a function. It has some variables -as attributes- and some functions -as method- You can define variables, you can initialize them. But you can't do any operation on them outside of a method...
for example
public static $var1; // OK!
public static $var2=5; //OK!
public static $var3=5+5; //ERROR
If you want to set them like this you must use constructor... (but remember: constructors aren't called until the object is created...)
<?php
session_start();
$_SESSION['color'] = 'blue';
class utilities {
public static $color;
function __construct()
{
$this->color=$_SESSION['color'];
}
function display()
{
echo utilities::$color;
}
}
utilities::display(); //empty output, because constructor wasn't invoked...
$obj=new utilities();
echo "<br>".$obj->color;
?>

Answer 2

From the PHP manual:-
Like any other PHP static variable,
static properties may only be
initialized using a literal or
constant; expressions are not allowed.
So while you may initialize a static
property to an integer or array (for
instance), you may not initialize it
to another variable, to a function
return value, or to an object.
You say that you need your session variables to be stored globally? They are $_SESSION is what is known as a "super global"
<?php
class utilities {
public static $color = $_SESSION['color']; //see here
function display()
{
echo $_SESSION['color'];
}
}
utilities::display(); ?>