Question

In my project I’m processing data and working with the results. There is an abstract class which looks like the following:

class AbstractInterpreter
{
    public function interprete( $data )
    {
        throw new Exception('Abstract Parent, nothing implemented here');
    }
}

And then there are various different implementations of the AbstractInterpreter:

class FooInterpreter extends AbstractInterpreter
{
    public function interprete( $data )
    {
        return "resultFoo";
    }
}
class BarInterpreter extends AbstractInterpreter
{
    public function interprete( $data )
    {
        return "resultBar";
    }
}

My calling code creates the interpreters and collects the results:

//this is the data we're working with
$data = "AnyData";

//create the interpreters
$interpreters = array();
$foo = new FooInterpreter();
$bar = new BarInterpreter();
$interpreters[] = $foo;
$interpreters[] = $bar;

//collect the results
$results = array();
foreach ($interpreters as $currentInterpreter)
{
    $results[] = $currentInterpreter->interprete($data);
}

I’m currently creating more and more interpreters and the code gets messy… For each interpreter I need to add a certain include_once(..) and I have to instantiate it and put it into the $interpreters.

Now, to finally ask my question:
Is it possible to automatically include and instantiate all interpreters that are in a specific directory and put them into the $interpreters?

In other languages this would be some kind of a plugin-concept:
I create different implementations of AbstractInterpreter, put them in a specific subdirectory and the software uses them automatically. I would not have to modify the code which loads the interpreters as soon as it is finished.

Answer 1

I don’t know if it’s possible automatically, but you can write a few lines code to get the same result.

function includeInterpreters($path) {

    $interpreters=array();

    if ($dh = opendir($path)) {
        while (($file = readdir($dh)) !== false) {

            include_once($path.$file);
            $fileNameParts=explode('.', $file);
            $interpreters[]=new $fileNameParts[0];

        }
        closedir($dh);
    }

    return $interpreters;
}

$interpreters= includeInterpreters('/path/plugins');

Name your class files as InterpreterName.php and put into the same directory, for example plugings

And yes, this looks messy.