Fix Trim for Sybase ASE

Author: fredericDelaporte

src/NHibernate/Dialect/Function/AnsiTrimEmulationFunction.cs

@@ -5,7 +5,6 @@
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
 using NHibernate.Type;
-using NHibernate.Util;
 using System.Text.RegularExpressions;
 
 namespace NHibernate.Dialect.Function
@@ -41,6 +40,40 @@ public class AnsiTrimEmulationFunction : ISQLFunction, IFunctionGrammar
 			new SQLFunctionTemplate(NHibernateUtil.String,
 			                        "replace( replace( ltrim( rtrim( replace( replace( ?1, ' ', '${space}$' ), ?2, ' ' ) ) ), ' ', ?2 ), '${space}$', ' ' )");
 
+		private readonly ISQLFunction _leadingTrim = LeadingTrim;
+		private readonly ISQLFunction _trailingTrim = TrailingTrim;
+		private readonly ISQLFunction _bothTrim = BothTrim;
+
+		/// <summary>
+		/// Default constructor. The target database has to support the <c>replace</c> function.
+		/// </summary>
+		public AnsiTrimEmulationFunction()
+		{
+		}
+
+		/// <summary>
+		/// Constructor for supplying the name of the replace function to use.
+		/// </summary>
+		/// <param name="replaceFunction">The replace function.</param>
+		public AnsiTrimEmulationFunction(string replaceFunction)
+		{
+			_leadingTrim =
+				new SQLFunctionTemplate(
+					NHibernateUtil.String,
+					$"{replaceFunction}( {replaceFunction}( ltrim( {replaceFunction}( {replaceFunction}( ?1, ' ', " +
+					"'${space}$' ), ?2, ' ' ) ), ' ', ?2 ), '${space}$', ' ' )");
+			_trailingTrim =
+				new SQLFunctionTemplate(
+					NHibernateUtil.String,
+					$"{replaceFunction}( {replaceFunction}( rtrim( {replaceFunction}( {replaceFunction}( ?1, ' ', " +
+					"'${space}$' ), ?2, ' ' ) ), ' ', ?2 ), '${space}$', ' ' )");
+			_bothTrim =
+				new SQLFunctionTemplate(
+					NHibernateUtil.String,
+					$"{replaceFunction}( {replaceFunction}( ltrim( rtrim( {replaceFunction}( {replaceFunction}( ?1, ' ', " +
+					"'${space}$' ), ?2, ' ' ) ) ), ' ', ?2 ), '${space}$', ' ' )");
+		}
+
 		#region ISQLFunction Members
 
 		public IType ReturnType(IType columnType, IMapping mapping)
@@ -174,18 +207,18 @@ public SqlString Render(IList args, ISessionFactoryImplementor factory)
 
 				return TrailingSpaceTrim.Render(argsToUse, factory);
 			}
-			
+
 			if (leading && trailing)
 			{
-				return BothTrim.Render(argsToUse, factory);
+				return _bothTrim.Render(argsToUse, factory);
 			}
-			
+
 			if (leading)
 			{
-				return LeadingTrim.Render(argsToUse, factory);
+				return _leadingTrim.Render(argsToUse, factory);
 			}
-			
-			return TrailingTrim.Render(argsToUse, factory);
+
+			return _trailingTrim.Render(argsToUse, factory);
 		}
 
 		#endregion

src/NHibernate/Dialect/SybaseASE15Dialect.cs

@@ -105,7 +105,7 @@ public SybaseASE15Dialect()
 			RegisterFunction("square", new StandardSQLFunction("square"));
 			RegisterFunction("str", new StandardSQLFunction("str", NHibernateUtil.String));
 			RegisterFunction("tan", new StandardSQLFunction("tan", NHibernateUtil.Double));
-			// TODO RegisterFunction("trim", new SQLFunctionTemplate(NHibernateUtil.String, "ltrim(rtrim(?1))"));
+			RegisterFunction("trim", new AnsiTrimEmulationFunction("str_replace"));
 			RegisterFunction("upper", new StandardSQLFunction("upper"));
 			RegisterFunction("user", new NoArgSQLFunction("user", NHibernateUtil.String));
 			RegisterFunction("year", new StandardSQLFunction("year", NHibernateUtil.Int32));