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/Profile/ServerProfileInterface.php

@@ -0,0 +1,56 @@
+<?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\Profile;
+
+use Predis\Command\CommandInterface;
+
+/**
+ * A server profile defines features and commands supported by certain
+ * versions of Redis. Instances of Predis\Client should use a server
+ * profile matching the version of Redis in use.
+ *
+ * @author Daniele Alessandri <suppakilla@gmail.com>
+ */
+interface ServerProfileInterface
+{
+    /**
+     * Gets a profile version corresponding to a Redis version.
+     *
+     * @return string
+     */
+    public function getVersion();
+
+    /**
+     * Checks if the profile supports the specified command.
+     *
+     * @param  string $command Command ID.
+     * @return bool
+     */
+    public function supportsCommand($command);
+
+    /**
+     * Checks if the profile supports the specified list of commands.
+     *
+     * @param  array  $commands List of command IDs.
+     * @return string
+     */
+    public function supportsCommands(Array $commands);
+
+    /**
+     * Creates a new command instance.
+     *
+     * @param  string           $method    Command ID.
+     * @param  array            $arguments Arguments for the command.
+     * @return CommandInterface
+     */
+    public function createCommand($method, $arguments = array());
+}