Support left and right functions in hql

Author: bahusoid

src/NHibernate.Test/Async/Legacy/SQLFunctionsTest.cs

@@ -116,6 +116,34 @@ public async Task DialectSQLFunctionsAsync()
 			s.Close();
 		}
 
+		//NH-3893 (GH-1349) left and right functions are broken
+		[Test]
+		public async Task LeftAndRightAsync()
+		{
+			//left or right functions are supported by most dialects but not registered.
+			if (!(Dialect is MsSql2000Dialect || Dialect is SQLiteDialect))
+				Assert.Ignore("left or right function is not supported by dialect");
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				Simple simple = new Simple();
+				simple.Name = "Simple Dialect Function Test";
+				simple.Address = "Simple Address";
+				simple.Pay = 45.8f;
+				simple.Count = 2;
+				await (s.SaveAsync(simple, 10L));
+
+				var rset = await (s.CreateQuery("select left('abc', 2), right('abc', 2) from s in class Simple").ListAsync<object[]>());
+				var row = rset[0];
+				Assert.AreEqual("ab", row[0], "Left function is broken.");
+				Assert.AreEqual("bc", row[1], "Right function is broken.");
+
+				await (s.DeleteAsync(simple));
+				await (t.CommitAsync());
+			}
+		}
+
 		[Test]
 		public async Task SetPropertiesAsync()
 		{

src/NHibernate.Test/Legacy/SQLFunctionsTest.cs

@@ -105,19 +105,30 @@ public void DialectSQLFunctions()
 			s.Close();
 		}
 
+		//NH-3893 (GH-1349) left and right functions are broken
 		[Test]
-		[Ignore("NH-3893 is not fixed")]
 		public void LeftAndRight()
 		{
-			// As of NH-3893, left and right functions are broken. Seemed confused with join keyword, and not
-			// supported on Hibernate side.
+			//left or right functions are supported by most dialects but not registered.
+			if (!(Dialect is MsSql2000Dialect || Dialect is SQLiteDialect))
+				Assert.Ignore("left or right function is not supported by dialect");
+
 			using (var s = OpenSession())
 			using (var t = s.BeginTransaction())
 			{
+				Simple simple = new Simple();
+				simple.Name = "Simple Dialect Function Test";
+				simple.Address = "Simple Address";
+				simple.Pay = 45.8f;
+				simple.Count = 2;
+				s.Save(simple, 10L);
+
 				var rset = s.CreateQuery("select left('abc', 2), right('abc', 2) from s in class Simple").List<object[]>();
 				var row = rset[0];
 				Assert.AreEqual("ab", row[0], "Left function is broken.");
 				Assert.AreEqual("bc", row[1], "Right function is broken.");
+
+				s.Delete(simple);
 				t.Commit();
 			}
 		}

src/NHibernate/Hql/Ast/ANTLR/HqlParser.cs

@@ -131,6 +131,18 @@ public void WeakKeywords()
 						}
 					}
 					break;
+				case LEFT:
+				case RIGHT:
+					// Support left and right functions
+					if (input.LA(2) == OPEN)
+					{
+						input.LT(1).Type = IDENT;
+						if (log.IsDebugEnabled())
+						{
+							log.Debug("weakKeywords() : new LT(1) token - {0}", input.LT(1));
+						}
+					}
+					break;
 				default:
 					// Case 2: The current token is after FROM and before '.'.
                     if (t != IDENT && input.LA(-1) == FROM && ((input.LA(2) == DOT) || (input.LA(2) == IDENT) || (input.LA(2) == -1)))