Question: I'm searching for following issue i have.
The class file names of our project are named logon.class.php
But the interface file for that class is named logon.interface.php

My issue i have is that when the autoload method runs I should be able to detect if it is a class call or an interface call.

```
<?php 
function __autoload($name){
    if($name === is_class){
        include_once($name.'class.php');
    }elseif ($name === is_interface){
         include_once($name.'interface.php');
    }
}
?>

```

Answer: 
You can use [ReflectionClass::isInterface](http://au.php.net/manual/en/reflectionclass.isinterface.php) to determine if the class is an interface.

```
$reflection = new ReflectionClass($name);

if ($reflection->isInterface()){
  //Is an interface
}else{
  //Not an interface
}

```

In your case, you would probably have to use `file_exist` first on `$name.interface.php` and `$name.class.php` to determine if they exist, require the one that exists, then check if it's an interface.

However, my opinion is that this might cause problems down the track. What if you have `MyClass.class.php` and `MyClass.interface.php`?
You should have some naming conventions for your classes and interfaces e.g. your class name is `logon` and interface name `logon_interface`, then you can easily differentiate between the two. For example, explode `$name` by underscore and check if last element is `interface`.