Make ExecuteCommand() work with JavaScript var statements. Add unit tests.

ClearScript/V8/V8/V8Patch.txt

@@ -1,6 +1,6 @@
 Index: tools/gyp/v8.gyp
 ===================================================================
---- tools/gyp/v8.gyp	(revision 13599)
+--- tools/gyp/v8.gyp	(revision 13624)
 +++ tools/gyp/v8.gyp	(working copy)
 @@ -32,6 +32,7 @@
        'targets': [

ClearScript/V8/V8ScriptEngine.cs

@@ -277,7 +277,11 @@ namespace Microsoft.ClearScript.V8
         /// </remarks>
         public override string ExecuteCommand(string command)
         {
-            return base.ExecuteCommand(MiscHelpers.FormatInvariant("EngineInternal.getCommandResult({0})", command));
+            return ScriptInvoke(() =>
+            {
+                Script.EngineInternal.command = command;
+                return base.ExecuteCommand("EngineInternal.getCommandResult(eval(EngineInternal.command))");
+            });
         }
 
         /// <summary>

ClearScript/Windows/JScriptEngine.cs

@@ -244,7 +244,8 @@ namespace Microsoft.ClearScript.Windows
         /// </remarks>
         public override string ExecuteCommand(string command)
         {
-            return base.ExecuteCommand(MiscHelpers.FormatInvariant("EngineInternal.getCommandResult({0})", command));
+            Script.EngineInternal.command = command;
+            return base.ExecuteCommand("EngineInternal.getCommandResult(eval(EngineInternal.command))");
         }
 
         internal override IDictionary<int, string> RuntimeErrorMap

ClearScript/Windows/VBScriptEngine.cs

@@ -121,6 +121,7 @@ namespace Microsoft.ClearScript.Windows
         };
 
         #endregion
+
         #region constructors
 
         /// <summary>

ClearScriptTest/JScriptEngineTest.cs

@@ -299,6 +299,20 @@ namespace Microsoft.ClearScript.Test
             Assert.AreEqual(dateHostItem.ToString(), engine.ExecuteCommand("date"));
         }
 
+        [TestMethod, TestCategory("JScriptEngine")]
+        public void JScriptEngine_ExecuteCommand_var()
+        {
+            Assert.AreEqual("[undefined]", engine.ExecuteCommand("var x = 'foo'"));
+            Assert.AreEqual("foo", engine.Script.x);
+        }
+
+        [TestMethod, TestCategory("JScriptEngine")]
+        public void JScriptEngine_ExecuteCommand_HostVariable()
+        {
+            engine.Script.host = new HostFunctions();
+            Assert.AreEqual("[HostVariable:String]", engine.ExecuteCommand("host.newVar('foo')"));
+        }
+
         [TestMethod, TestCategory("JScriptEngine")]
         public void JScriptEngine_Interrupt()
         {

ClearScriptTest/V8ScriptEngineTest.cs

@@ -302,6 +302,20 @@ namespace Microsoft.ClearScript.Test
             Assert.AreEqual(dateHostItem.ToString(), engine.ExecuteCommand("date"));
         }
 
+        [TestMethod, TestCategory("V8ScriptEngine")]
+        public void V8ScriptEngine_ExecuteCommand_var()
+        {
+            Assert.AreEqual("[undefined]", engine.ExecuteCommand("var x = 'foo'"));
+            Assert.AreEqual("foo", engine.Script.x);
+        }
+
+        [TestMethod, TestCategory("V8ScriptEngine")]
+        public void V8ScriptEngine_ExecuteCommand_HostVariable()
+        {
+            engine.Script.host = new HostFunctions();
+            Assert.AreEqual("[HostVariable:String]", engine.ExecuteCommand("host.newVar('foo')"));
+        }
+
         [TestMethod, TestCategory("V8ScriptEngine")]
         public void V8ScriptEngine_Interrupt()
         {
@@ -314,10 +328,13 @@ namespace Microsoft.ClearScript.Test
 
             engine.AddHostObject("checkpoint", checkpoint);
 
+            // V8 can't interrupt code that accesses only native data
+            engine.AddHostObject("test", new { foo = "bar" });
+
             var gotException = false;
             try
             {
-                engine.Execute("checkpoint.Set(); while (true) { var foo = 'hello'; }");
+                engine.Execute("checkpoint.Set(); while (true) { var foo = test.foo; }");
             }
             catch (OperationCanceledException)
             {

ClearScriptTest/VBScriptEngineTest.cs

@@ -325,6 +325,13 @@ namespace Microsoft.ClearScript.Test
             Assert.AreEqual(dateHostItem.ToString(), engine.ExecuteCommand("eval date"));
         }
 
+        [TestMethod, TestCategory("VBScriptEngine")]
+        public void VBScriptEngine_ExecuteCommand_HostVariable()
+        {
+            engine.Script.host = new HostFunctions();
+            Assert.AreEqual("[HostVariable:String]", engine.ExecuteCommand("eval host.newVar(\"foo\")"));
+        }
+
         [TestMethod, TestCategory("VBScriptEngine")]
         public void VBScriptEngine_Interrupt()
         {