You can now define object interfaces, which is a way to ensure
that a given class provides a certain set of functions you can rely on elsewhere.
<?php
interface read_file {
function open($file_name);
function read($bytes);
function close();
}
class rf implements read_file {
private $fp;
function open($file_name) { $this->fp = fopen($file_name, "r"); }
function read($bytes) { return fread($this->fp, $bytes); }
function close() { fclose($this->fp); }
}
$f = new rf();
/* ensure that object inside $ implements read_file interface */
if ($f instanceof read_file) {
$f->open(__FILE__);
echo $f->read(4);
$f->close();
}
?>
