-Fixed error with whitespace only JSONPath

-Fixed property query path that starts with $
-Fixed array query path with open brace after $

Src/Newtonsoft.Json.Tests/Converters/XmlNodeConverterTest.cs

@@ -1930,7 +1930,4 @@ namespace Newtonsoft.Json.Tests.Converters
         }
     }
 }
-
-#endif
-
-
+#endif

Src/Newtonsoft.Json.Tests/Linq/JsonPath/JPathExecuteTests.cs

@@ -50,6 +50,46 @@ namespace Newtonsoft.Json.Tests.Linq.JsonPath
     [TestFixture]
     public class JPathExecuteTests : TestFixtureBase
     {
+        [Test]
+        public void EvaluateEmptyString()
+        {
+            JObject o = new JObject(
+                new JProperty("Blah", 1));
+
+            JToken t = o.SelectToken("");
+            Assert.AreEqual(o, t);
+        }
+
+        [Test]
+        public void EvaluateWhitespaceString()
+        {
+            JObject o = new JObject(
+                new JProperty("Blah", 1));
+
+            JToken t = o.SelectToken(" ");
+            Assert.AreEqual(o, t);
+        }
+
+        [Test]
+        public void EvaluateDollarString()
+        {
+            JObject o = new JObject(
+                new JProperty("Blah", 1));
+
+            JToken t = o.SelectToken("$");
+            Assert.AreEqual(o, t);
+        }
+
+        [Test]
+        public void EvaluateDollarTypeString()
+        {
+            JObject o = new JObject(
+                new JProperty("$values", new JArray(1, 2, 3)));
+
+            JToken t = o.SelectToken("$values[1]");
+            Assert.AreEqual(2, (int)t);
+        }
+
         [Test]
         public void EvaluateSingleProperty()
         {

Src/Newtonsoft.Json.Tests/Linq/JsonPath/JPathParseTests.cs

@@ -141,6 +141,14 @@ namespace Newtonsoft.Json.Tests.Linq.JsonPath
             Assert.AreEqual(null, ((ArrayIndexFilter)path.Filters[0]).Index);
         }
 
+        [Test]
+        public void RootArrayNoDot()
+        {
+            JPath path = new JPath("$[1]");
+            Assert.AreEqual(1, path.Filters.Count);
+            Assert.AreEqual(1, ((ArrayIndexFilter)path.Filters[0]).Index);
+        }
+
         [Test]
         public void WildcardArray()
         {

Src/Newtonsoft.Json/Linq/JsonPath/JPath.cs

@@ -51,21 +51,24 @@ namespace Newtonsoft.Json.Linq.JsonPath
         {
             int currentPartStartIndex = _currentIndex;
 
-            if (_expression.Length == 0)
-                return;
-
             EatWhitespace();
 
+            if (_expression.Length == _currentIndex)
+                return;
+
             if (_expression[_currentIndex] == '$')
             {
-                _currentIndex++;
+                if (_expression.Length == 1)
+                    return;
 
-                EnsureLength("Unexpected end while parsing path.");
-
-                if (_expression[_currentIndex] != '.')
-                    throw new JsonException("Unexpected character while parsing path: " + _expression[_currentIndex]);
-
-                currentPartStartIndex = _currentIndex;
+                // only increment position for "$." or "$["
+                // otherwise assume property that starts with $
+                char c = _expression[_currentIndex + 1];
+                if (c == '.' || c == '[')
+                {
+                    _currentIndex++;
+                    currentPartStartIndex = _currentIndex;
+                }
             }
 
             if (!ParsePath(Filters, currentPartStartIndex, false))