Implemented alternate MULTI syntax

Usage:

  client
    .multi
    .set(foo, bar)
    .set(counter, 1)
    .incr(counter)
    .exec(function(err, replies){});

index.js

@@ -658,8 +658,9 @@ exports.commands = [
     "INFO", "MONITOR", "SLAVEOF", "CONFIG",
     // Publish/Subscribe
     "PUBLISH", "SUBSCRIBE", "PSUBSCRIBE", "UNSUBSCRIBE", "PUNSUBSCRIBE",
+    "MULTI", "EXEC",
     // Undocumented commands
-    "PING"
+    "PING",
 ];
 
 exports.commands.forEach(function (command) {
@@ -676,47 +677,43 @@ exports.commands.forEach(function (command) {
     };
 });
 
-// Transactions - "DISCARD", "WATCH", "UNWATCH",
+function Multi(client) {
+    this.client = client;
+    this.queue = [];
+    this.queue.push(['MULTI']);
+}
 
-RedisClient.prototype.multi = function (commands, callback) {
-    var self = this;
+exports.commands.forEach(function (command) {
+    Multi.prototype[command.toLowerCase()] = function () {
+        var args = to_array(arguments);
+        args.unshift(command); // put command at the beginning
+        this.queue.push(args);
+        return this;
+    };
+});
 
-    this.send_command("MULTI", function (err, reply) {
-        if (err) {
-            console.warn("Error starting MULTI request: " + err.stack);
-        }
-    });
-    commands.forEach(function (args, command_num) {
-        self.send_command(args[0], args[1], function (err, reply) {
+Multi.prototype.exec = function(fn){
+    var done;
+    this.queue.push(['EXEC']);
+    this.queue.forEach(function(args){
+        var command = args.shift();
+        this.client[command](args, function(err, reply){
+            if (done) return;
             if (err) {
-                args[2](err);
-                commands.splice(command_num, 1); // what if this runs before all commands are sent?
-            } else {
-                if (reply !== "QUEUED") {
-                    console.warn("Unexpected MULTI reply: " + reply + " instead of 'QUEUED'");
-                }
+                done = true;
+                fn(new Error(err));
+            } else if ('EXEC' == command) {
+                done = true;
+                fn(null, reply);
             }
         });
-    });
-    this.send_command("EXEC", function (err, replies) {
-        replies.forEach(function (reply, reply_num) {
-            if (typeof commands[reply_num][2] === "function") {
-                commands[reply_num][2](null, reply);
-            } else {
-                if (exports.debug_mode) {
-                    console.log("no callback for multi response " + reply_num + ", skipping.");
-                }
-            }
-        });
-        if (typeof callback === "function") {
-            callback(replies);
-        }
-    });
-};
-RedisClient.prototype.MULTI = function (commands) {
-    return this.multi(commands);
+    }, this);
 };
 
+RedisClient.prototype.__defineGetter__('multi', function(){
+    return new Multi(this);
+});
+
 exports.createClient = function (port_arg, host_arg, options) {
     var port = port_arg || default_port,
         host = host_arg || default_host,

test.js

@@ -339,30 +339,33 @@ tests.MSETNX = function () {
 
 tests.MULTI = function () {
     var name = "MULTI";
-    client.multi([
-        ["mset", ["multifoo", "10", "multibar", "20"], require_string("OK", name)],
-        ["set", ["foo2"], require_error(name)],
-        ["incr", ["multifoo"], require_number(11, name)],
-        ["incr", ["multibar"], require_number(21, name)]
-    ]);
 
-    client.multi([
-        ["incr", ["multibar"], require_number(22, name)],
-        ["incr", ["multifoo"], require_number(12, name)]
-    ]);
-    
-    client.multi([
-        ["mget", ["multifoo", "multibar"], function (err, res) {
-            assert.strictEqual(2, res.length, name);
-            assert.strictEqual("12", res[0].toString(), name);
-            assert.strictEqual("22", res[1].toString(), name);
-        }],
-        ["set", ["foo2"], require_error(name)],
-        ["incr", ["multifoo"], require_number(13, name)],
-        ["incr", ["multibar"], require_number(23, name)]
-    ], function (reply) {
-        next(name);
-    });
+    client
+      .multi
+      .mset('some', '10', 'keys', '20')
+      .incr('some')
+      .incr('keys')
+      .exec(function(err, replies){
+          assert.strictEqual(null, err);
+          assert.equal('OK', replies[0]);
+          assert.equal(11, replies[1]);
+          assert.equal(21, replies[2]);
+          next(name);
+      });
+};
+
+tests.MULTI_ERROR = function () {
+    var name = "MULTI_ERROR";
+
+    client
+      .multi
+      .set('something', 'amazing')
+      .set('invalid')
+      .exec(function(err, replies){
+          assert.equal("ERR wrong number of arguments for 'set' command", err.message);
+          assert.strictEqual(undefined, replies);
+          next(name);
+      });
 };
 
 tests.HGETALL = function () {