Add multiple arguments support for ISQLFunction

src/NHibernate/Criterion/SqlFunctionProjection.cs

@@ -125,7 +125,7 @@ private IType GetReturnType(ICriteria criteria, ICriteriaQuery criteriaQuery)
 
 			var resultType = returnType ?? returnTypeProjection?.GetTypes(criteria, criteriaQuery).FirstOrDefault();
 
-			return sqlFunction.ReturnType(resultType, criteriaQuery.Factory);
+			return sqlFunction.GetReturnType(new[] {resultType}, criteriaQuery.Factory, true);
 		}
 
 		public override TypedValue[] GetTypedValues(ICriteria criteria, ICriteriaQuery criteriaQuery)

src/NHibernate/Dialect/DB2Dialect.cs

@@ -131,7 +131,7 @@ public DB2Dialect()
 			RegisterFunction("length", new StandardSQLFunction("length", NHibernateUtil.Int32));
 			RegisterFunction("ltrim", new StandardSQLFunction("ltrim"));
 
-			RegisterFunction("mod", new StandardSQLFunction("mod", NHibernateUtil.Int32));
+			RegisterFunction("mod", new ModulusFunction(true, false));
 
 			RegisterFunction("substring", new StandardSQLFunction("substr", NHibernateUtil.String));
 

src/NHibernate/Dialect/Dialect.cs

@@ -94,7 +94,7 @@ protected Dialect()
 			RegisterFunction("coalesce", new StandardSQLFunction("coalesce"));
 			RegisterFunction("nullif", new StandardSQLFunction("nullif"));
 			RegisterFunction("abs", new StandardSQLFunction("abs"));
-			RegisterFunction("mod", new StandardSQLFunction("mod", NHibernateUtil.Int32));
+			RegisterFunction("mod", new ModulusFunction(false, false));
 			RegisterFunction("sqrt", new StandardSQLFunction("sqrt", NHibernateUtil.Double));
 			RegisterFunction("upper", new StandardSQLFunction("upper"));
 			RegisterFunction("lower", new StandardSQLFunction("lower"));

src/NHibernate/Dialect/FirebirdDialect.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections;
+using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
 using NHibernate.Dialect.Function;
@@ -147,7 +148,7 @@ public CastedFunction(string name, IType returnType) : base(name, returnType, fa
 
 			public override SqlString Render(IList args, ISessionFactoryImplementor factory)
 			{
-				return new SqlString("cast('", Name, "' as ", FunctionReturnType.SqlTypes(factory)[0].ToString(), ")");
+				return new SqlString("cast('", FunctionName, "' as ", FunctionReturnType.SqlTypes(factory)[0].ToString(), ")");
 			}
 		}
 
@@ -160,7 +161,7 @@ public CurrentTimeStamp() : base("current_timestamp", NHibernateUtil.LocalDateTi
 
 			public override SqlString Render(IList args, ISessionFactoryImplementor factory)
 			{
-				return new SqlString(Name);
+				return new SqlString(FunctionName);
 			}
 		}
 
@@ -205,7 +206,7 @@ public override string SelectGUIDString
 		}
 
 		[Serializable]
-		private class PositionFunction : ISQLFunction
+		private class PositionFunction : ISQLFunction, ISQLFunctionExtended
 		{
 			// The cast is needed, at least in the case that ?3 is a named integer parameter, otherwise firebird will generate an error.  
 			// We have a unit test to cover this potential firebird bug.
@@ -214,11 +215,28 @@ private class PositionFunction : ISQLFunction
 			private static readonly ISQLFunction LocateWith3Params = new SQLFunctionTemplate(NHibernateUtil.Int32,
 				"position(?1, ?2, cast(?3 as int))");
 
+			// Since v5.3
+			[Obsolete("Use GetReturnType method instead.")]
 			public IType ReturnType(IType columnType, IMapping mapping)
 			{
 				return NHibernateUtil.Int32;
 			}
 
+			/// <inheritdoc />
+			public IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+			{
+				return NHibernateUtil.Int32;
+			}
+
+			/// <inheritdoc />
+			public IType GetEffectiveReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+			{
+				return GetReturnType(argumentTypes, mapping, throwOnError);
+			}
+
+			/// <inheritdoc />
+			public string FunctionName => "position";
+
 			public bool HasArguments
 			{
 				get { return true; }
@@ -418,7 +436,8 @@ private void OverrideStandardHQLFunctions()
 			RegisterFunction("nullif", new StandardSafeSQLFunction("nullif", 2));
 			RegisterFunction("lower", new StandardSafeSQLFunction("lower", NHibernateUtil.String, 1));
 			RegisterFunction("upper", new StandardSafeSQLFunction("upper", NHibernateUtil.String, 1));
-			RegisterFunction("mod", new StandardSafeSQLFunction("mod", NHibernateUtil.Double, 2));
+			// Modulo does not throw for decimal parameters but they are casted to int by Firebird, which produces unexpected results
+			RegisterFunction("mod", new ModulusFunction(false, false));
 			RegisterFunction("str", new SQLFunctionTemplate(NHibernateUtil.String, "cast(?1 as VARCHAR(255))"));
 			RegisterFunction("strguid", new StandardSQLFunction("uuid_to_char", NHibernateUtil.String));
 			RegisterFunction("sysdate", new CastedFunction("today", NHibernateUtil.Date));
@@ -437,7 +456,7 @@ private void RegisterFirebirdServerEmbeddedFunctions()
 			RegisterFunction("yesterday", new CastedFunction("yesterday", NHibernateUtil.Date));
 			RegisterFunction("tomorrow", new CastedFunction("tomorrow", NHibernateUtil.Date));
 			RegisterFunction("now", new CastedFunction("now", NHibernateUtil.DateTime));
-			RegisterFunction("iif", new StandardSafeSQLFunction("iif", 3));
+			RegisterFunction("iif", new IifSafeSQLFunction());
 			// New embedded functions in FB 2.0 (http://www.firebirdsql.org/rlsnotes20/rnfbtwo-str.html#str-string-func)
 			RegisterFunction("char_length", new StandardSafeSQLFunction("char_length", NHibernateUtil.Int64, 1));
 			RegisterFunction("bit_length", new StandardSafeSQLFunction("bit_length", NHibernateUtil.Int64, 1));

src/NHibernate/Dialect/Function/AnsiSubstringFunction.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
 using System.Text;
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
@@ -22,15 +24,34 @@ namespace NHibernate.Dialect.Function
 	///]]>
 	/// </remarks>
 	[Serializable]
-	public class AnsiSubstringFunction : ISQLFunction
+	public class AnsiSubstringFunction : ISQLFunction, ISQLFunctionExtended
 	{
 		#region ISQLFunction Members
 
+		// Since v5.3
+		[Obsolete("Use GetReturnType method instead.")]
 		public IType ReturnType(IType columnType, IMapping mapping)
 		{
 			return NHibernateUtil.String;
 		}
 
+		/// <inheritdoc />
+		public IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+#pragma warning disable 618
+			return ReturnType(argumentTypes.FirstOrDefault(), mapping);
+#pragma warning restore 618
+		}
+
+		/// <inheritdoc />
+		public IType GetEffectiveReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+			return GetReturnType(argumentTypes, mapping, throwOnError);
+		}
+
+		/// <inheritdoc />
+		public string FunctionName => "substring";
+
 		public bool HasArguments
 		{
 			get { return true; }

src/NHibernate/Dialect/Function/AnsiTrimEmulationFunction.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
-
+using System.Linq;
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
 using NHibernate.Type;
@@ -17,7 +17,7 @@ namespace NHibernate.Dialect.Function
 	/// functionality.
 	/// </summary>
 	[Serializable]
-	public class AnsiTrimEmulationFunction : ISQLFunction, IFunctionGrammar
+	public class AnsiTrimEmulationFunction : ISQLFunction, IFunctionGrammar, ISQLFunctionExtended
 	{
 		private static readonly ISQLFunction LeadingSpaceTrim = new SQLFunctionTemplate(NHibernateUtil.String, "ltrim( ?1 )");
 		private static readonly ISQLFunction TrailingSpaceTrim = new SQLFunctionTemplate(NHibernateUtil.String, "rtrim( ?1 )");
@@ -76,11 +76,30 @@ public AnsiTrimEmulationFunction(string replaceFunction)
 
 		#region ISQLFunction Members
 
+		// Since v5.3
+		[Obsolete("Use GetReturnType method instead.")]
 		public IType ReturnType(IType columnType, IMapping mapping)
 		{
 			return NHibernateUtil.String;
 		}
 
+		/// <inheritdoc />
+		public IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+#pragma warning disable 618
+			return ReturnType(argumentTypes.FirstOrDefault(), mapping);
+#pragma warning restore 618
+		}
+
+		/// <inheritdoc />
+		public IType GetEffectiveReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+			return GetReturnType(argumentTypes, mapping, throwOnError);
+		}
+
+		/// <inheritdoc />
+		public string FunctionName => null;
+
 		public bool HasArguments
 		{
 			get { return true; }

src/NHibernate/Dialect/Function/AvgQueryFunctionInfo.cs

@@ -1,6 +1,6 @@
 using System;
+using System.Collections.Generic;
 using NHibernate.Engine;
-using NHibernate.SqlTypes;
 using NHibernate.Type;
 
 namespace NHibernate.Dialect.Function
@@ -10,27 +10,22 @@ class AvgQueryFunctionInfo : ClassicAggregateFunction
 	{
 		public AvgQueryFunctionInfo() : base("avg", false) { }
 
+		// Since v5.3
+		[Obsolete("Use GetReturnType method instead.")]
 		public override IType ReturnType(IType columnType, IMapping mapping)
 		{
-			if (columnType == null)
-			{
-				throw new ArgumentNullException("columnType");
-			}
-			SqlType[] sqlTypes;
-			try
-			{
-				sqlTypes = columnType.SqlTypes(mapping);
-			}
-			catch (MappingException me)
-			{
-				throw new QueryException(me);
-			}
+			return GetReturnType(new[] {columnType}, mapping, true);
+		}
 
-			if (sqlTypes.Length != 1)
+		/// <inheritdoc />
+		public override IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+			if (!TryGetArgumentType(argumentTypes, mapping, throwOnError, out _, out _))
 			{
-				throw new QueryException("multi-column type can not be in avg()");
+				return null;
 			}
+
 			return NHibernateUtil.Double;
 		}
 	}
-}
+}

src/NHibernate/Dialect/Function/BitwiseFunctionOperation.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
 using NHibernate.Type;
@@ -27,8 +29,9 @@ namespace NHibernate.Dialect.Function
 	/// Treats bitwise operations as SQL function calls.
 	/// </summary>
 	[Serializable]
-	public class BitwiseFunctionOperation : ISQLFunction
+	public class BitwiseFunctionOperation : ISQLFunction, ISQLFunctionExtended
 	{
+		// TODO 6.0: convert FunctionName to read-only auto-property
 		private readonly string _functionName;
 
 		/// <summary>
@@ -45,11 +48,30 @@ public BitwiseFunctionOperation(string functionName)
 		#region ISQLFunction Members
 
 		/// <inheritdoc />
+		// Since v5.3
+		[Obsolete("Use GetReturnType method instead.")]
 		public IType ReturnType(IType columnType, IMapping mapping)
 		{
 			return NHibernateUtil.Int64;
 		}
 
+		/// <inheritdoc />
+		public IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+#pragma warning disable 618
+			return ReturnType(argumentTypes.FirstOrDefault(), mapping);
+#pragma warning restore 618
+		}
+
+		/// <inheritdoc />
+		public virtual IType GetEffectiveReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+			return GetReturnType(argumentTypes, mapping, throwOnError);
+		}
+
+		/// <inheritdoc />
+		public string FunctionName => _functionName;
+
 		/// <inheritdoc />
 		public bool HasArguments => true;
 

src/NHibernate/Dialect/Function/BitwiseNativeOperation.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
 using NHibernate.Type;
@@ -32,7 +34,7 @@ namespace NHibernate.Dialect.Function
 	/// Treats bitwise operations as native operations.
 	/// </summary>
 	[Serializable]
-	public class BitwiseNativeOperation : ISQLFunction
+	public class BitwiseNativeOperation : ISQLFunction, ISQLFunctionExtended
 	{
 		private readonly string _sqlOpToken;
 		private readonly bool _isUnary;
@@ -65,11 +67,30 @@ public BitwiseNativeOperation(string sqlOpToken, bool isUnary)
 		#region ISQLFunction Members
 
 		/// <inheritdoc />
+		// Since v5.3
+		[Obsolete("Use GetReturnType method instead.")]
 		public IType ReturnType(IType columnType, IMapping mapping)
 		{
 			return NHibernateUtil.Int64;
 		}
 
+		/// <inheritdoc />
+		public IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+#pragma warning disable 618
+			return ReturnType(argumentTypes.FirstOrDefault(), mapping);
+#pragma warning restore 618
+		}
+
+		/// <inheritdoc />
+		public virtual IType GetEffectiveReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+			return GetReturnType(argumentTypes, mapping, throwOnError);
+		}
+
+		/// <inheritdoc />
+		public string FunctionName => null;
+
 		/// <inheritdoc />
 		public bool HasArguments => true;
 

src/NHibernate/Dialect/Function/CastFunction.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
 using System.Xml;
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
@@ -12,17 +14,36 @@ namespace NHibernate.Dialect.Function
 	/// ANSI-SQL style cast(foo as type) where the type is a NHibernate type
 	/// </summary>
 	[Serializable]
-	public class CastFunction : ISQLFunction, IFunctionGrammar
+	public class CastFunction : ISQLFunction, IFunctionGrammar, ISQLFunctionExtended
 	{
 		#region ISQLFunction Members
 
+		// Since v5.3
+		[Obsolete("Use GetReturnType method instead.")]
 		public IType ReturnType(IType columnType, IMapping mapping)
 		{
 			//note there is a weird implementation in the client side
 			//TODO: cast that use only costant are not supported in SELECT. Ex: cast(5 as string)
 			return columnType;
 		}
 
+		/// <inheritdoc />
+		public IType GetReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+#pragma warning disable 618
+			return ReturnType(argumentTypes.FirstOrDefault(), mapping);
+#pragma warning restore 618
+		}
+
+		/// <inheritdoc />
+		public virtual IType GetEffectiveReturnType(IEnumerable<IType> argumentTypes, IMapping mapping, bool throwOnError)
+		{
+			return GetReturnType(argumentTypes, mapping, throwOnError);
+		}
+
+		/// <inheritdoc />
+		public string FunctionName => "cast";
+
 		public bool HasArguments
 		{
 			get { return true; }