File private variables in PHP

Ok, I probably get for this, but if you are completely desperate to use the Registry to do this, I hacked a little one that does no classes (since I assume there is no OOP here, so I am not looking for private members of the class, hence you don't want to do it with OOP at all)

function &registry_get_instance()
{
    static $data = array();
    return $data;
}

      

        
        
        
      

    

static $data

variable is internally stored inside the function scope, so you can call the function wherever you want and always get the same content. The decisive point is the return by reference , for example

$registry = &registry_get_instance();     // get $data array by reference
$registry['foo'] = 'bar';                 // set something to $data
unset($registry);                         // delete global reference to $data
print_r(&registry_get_instance());        // show $data 

      

        
        
        
      

    

Obviously, you must still have $ registry as a variable in the global scope when calling this method from the global scope. This way, you can add a few more functions to make the registry more usable, for example. to set data to the registry:

function registry_set($key, $value) 
{
    $registry = &registry_get_instance();
    $registry[$key] = $value;
}

      

        
        
        
      

    

and to get it:

function registry_get($key)
{
    $registry = &registry_get_instance();
    if(array_key_exists($key, $registry)) {
        return $registry[$key];
    } else {
        trigger_error(sprintf(
            'Undefined Index: %s', htmlentities($key)
        ), E_USER_NOTICE);
    }
}

      

        
        
        
      

    

and to check if a key exists:

function registry_isset($key)
{
    $registry = &registry_get_instance();
    return array_key_exists($key, $registry);
}

      

        
        
        
      

    

which you could use like this:

registry_set('foo', 'bar');         // setting something to the registry
var_dump( registry_isset('foo') );  // check foo is in the registry now
echo registry_get('foo');           // prints 'bar'
echo registry_get('punt');          // raises Notice

      

        
        
        
      

    

You can populate the registry from the include file with an additional method like this:

function registry_load_file($file)
{
    if(!is_readable(realpath($file))) {
        return trigger_error(sprintf(
            'File is not readable: %s', htmlentities($file)
        ), E_USER_WARNING);
    }
    $config = include $file;
    if(!is_array($config)) {
        return trigger_error(sprintf(
            'Expected file %s to return an array', htmlentities($file))
        , E_USER_WARNING);
    }
    $registry = &registry_get_instance();
    $registry += $config;
}

      

        
        
        
      

    

with an included file that should return an array:

// config.php
return array(
    'setting1' => 'something'
);

      

        
        
        
      

    

and then you can do

registry_load_from_file('config.php');  // add the contents of config to registry
print_r(registry_get_instance());       // show content of registry

      

        
        
        
      

    

Of course there are now six functions in the global scope just to not have a global variable. Don't know if it's worth it, especially since I'm considering static

in functions and all this reference information a dubious practice.

Let's take this as a proof of concept :)