Retwis ported to modern Redis data types.

The example (and related documentation at redis.io) was not updated for
5 years. Redis had no sorted sets and hashes when the original code was
written (!). An update was really needed.

We also use a modern PHP client now: Predis. A copy is shipped within
this repository to make life easier to newcomers trying Redis for the
first time via this example.

Predis/Protocol/ComposableProtocolInterface.php

@@ -0,0 +1,50 @@
+<?php
+
+/*
+ * This file is part of the Predis package.
+ *
+ * (c) Daniele Alessandri <suppakilla@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Predis\Protocol;
+
+/**
+ * Interface that defines a customizable protocol processor that serializes
+ * Redis commands and parses replies returned by the server to PHP objects
+ * using a pluggable set of classes defining the underlying wire protocol.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface ComposableProtocolInterface extends ProtocolInterface
+{
+    /**
+     * Sets the command serializer to be used by the protocol processor.
+     *
+     * @param CommandSerializerInterface $serializer Command serializer.
+     */
+    public function setSerializer(CommandSerializerInterface $serializer);
+
+    /**
+     * Returns the command serializer used by the protocol processor.
+     *
+     * @return CommandSerializerInterface
+     */
+    public function getSerializer();
+
+    /**
+     * Sets the response reader to be used by the protocol processor.
+     *
+     * @param ResponseReaderInterface $reader Response reader.
+     */
+    public function setReader(ResponseReaderInterface $reader);
+
+    /**
+     * Returns the response reader used by the protocol processor.
+     *
+     * @return ResponseReaderInterface
+     */
+    public function getReader();
+}