implicit this reference #232.

src/DynamicExpresso.Core/LanguageConstants.cs

@@ -6,6 +6,8 @@ namespace DynamicExpresso
 {
 	public static class LanguageConstants
 	{
+		public const string This = "this";
+
 		public static readonly ReferenceType[] PrimitiveTypes = {
             new ReferenceType(typeof(object)),
             new ReferenceType(typeof(bool)),

src/DynamicExpresso.Core/Parsing/Parser.cs

@@ -1019,12 +1019,31 @@ private Expression ParseIdentifier()
 			{
 				return ParseTypeKeyword(knownType);
 			}
-
+
+			var token = _token;
+
+			try
+			{
+				if (_arguments.TryGetIdentifier(LanguageConstants.This, out var thisKeywordExpression))
+				{
+					return ParseMemberAccess(thisKeywordExpression);
+				}
+
+				if (_arguments.TryGetParameters(LanguageConstants.This, out var thisParameterExpression))
+				{
+					return ParseMemberAccess(thisParameterExpression);
+				}
+			}
+			catch(ParseException)
+			{
+				// ignore
+			}
+
 			// Working context implementation
 			//if (it != null)
 			//    return ParseMemberAccess(null, it);
 
-			throw new UnknownIdentifierException(_token.text, _token.pos);
+			throw new UnknownIdentifierException(token.text, token.pos);
 		}
 
 		// Working context implementation

test/DynamicExpresso.UnitTest/IdentifiersTest.cs

@@ -1,4 +1,5 @@
-using System.Linq;
+using System.Collections.Generic;
+using System.Linq;
 using NUnit.Framework;
 
 namespace DynamicExpresso.UnitTest
@@ -38,5 +39,38 @@ public void Getting_the_list_of_used_identifiers()
 			Assert.AreEqual("x", lambda.Identifiers.ElementAt(0).Name);
 			Assert.AreEqual("true", lambda.Identifiers.ElementAt(1).Name);
 		}
+
+		[Test]
+		public void This_identifier_variable()
+		{
+			const string Name = "John";
+			var context = new KeyValuePair<string, string>(nameof(Name), Name);
+
+			var interpreter = new Interpreter();
+
+			interpreter.SetVariable("this", context);
+
+			Assert.AreEqual(Name, interpreter.Eval("this.Value"));
+			Assert.AreEqual(nameof(Name), interpreter.Eval("this.Key"));
+
+			Assert.AreEqual(Name, interpreter.Eval("Value"));
+			Assert.AreEqual(nameof(Name), interpreter.Eval("Key"));
+		}
+
+		[Test]
+		public void This_identifier_parameter()
+		{
+			const string Name = "John";
+			var context = new KeyValuePair<string, string>(nameof(Name), Name);
+			var parameter = new Parameter("this", context.GetType());
+
+			var interpreter = new Interpreter();
+
+			Assert.AreEqual(Name, interpreter.Parse("this.Value", parameter).Invoke(context));
+			Assert.AreEqual(nameof(Name), interpreter.Parse("this.Key", parameter).Invoke(context));
+
+			Assert.AreEqual(Name, interpreter.Parse("Value", parameter).Invoke(context));
+			Assert.AreEqual(nameof(Name), interpreter.Parse("Key", parameter).Invoke(context));
+		}
 	}
 }