#104 Ok with this keyword. this keyword is automatically set as the context object

Author: codingseb

CodingSeb.ExpressionEvaluator.Tests/ExpressionEvaluatorTests.cs

@@ -1643,6 +1643,7 @@ public void Evaluate_ParameterTypeMismatchAutoAdapt()
 
         /// <summary>
         /// To correct #104 Extension methods do not work on context
+        /// work now with this keyword like in C#
         /// </summary>
         [Test]
         [Category("Bug")]
@@ -1657,10 +1658,28 @@ public void Evaluate_ExtensionMethodOnContext()
                 }
             };
 
-            evaluator.Evaluate("Sum()")
+            evaluator.Evaluate("this.Sum()")
                 .ShouldBe(15);
         }
 
+        /// <summary>
+        /// To correct #104 Indexing do not work on context
+        /// work now with this keyword like in C#
+        /// </summary>
+        [Test]
+        [Category("Bug")]
+        [Category("#104")]
+        public void Evaluate_IndexingOnContext()
+        {
+            var evaluator = new ExpressionEvaluator
+            {
+                Context = new ClassForIndexing()
+            };
+
+            evaluator.Evaluate("this[\"Test\"]")
+                .ShouldBe("TestTest");
+        }
+
         /// <summary>
         /// To correct #105 Exception were not thrown when concat with string
         /// </summary>

CodingSeb.ExpressionEvaluator/ExpressionEvaluator.cs

@@ -336,6 +336,7 @@ protected enum TryBlockEvaluatedState
             { "null", null},
             { "true", true },
             { "false", false },
+            { "this", null }
         };
 
         protected IDictionary<string, Func<double, double>> simpleDoubleMathFuncsDictionary = new Dictionary<string, Func<double, double>>(StringComparer.Ordinal)
@@ -872,10 +873,20 @@ protected virtual BindingFlags StaticBindingFlag
 
         #region Custom and on the fly evaluation
 
+        private object context;
+
         /// <summary>
         /// If set, this object is used to use it's fields, properties and methods as global variables and functions
         /// </summary>
-        public object Context { get; set; }
+        public object Context
+        {
+            get { return context; }
+            set
+            {
+                context = value;
+                defaultVariables["this"] = context;
+            }
+        }
 
         private IDictionary<string, object> variables = new Dictionary<string, object>(StringComparer.Ordinal);