Parser/Elements/ExpressionPart.cs

@@ -4,11 +4,11 @@ namespace XNeedle.Parser.Elements
 {
     public class ExpressionPart : Part
     {
-        public required Expression<Func<string>> Expr { get; set; }
+        public required Expression<Func<Context, string>> Expr { get; set; }
 
-        public override void Operate(Context xtx)
+        public override void Operate(Context ctx)
         {
-            Expr.Compile()();
+            Expr.Compile()(ctx);
         }
     }
 }

Parser/XnParser.cs

@@ -13,6 +13,8 @@ namespace XNeedle.Parser
 {
         public class XnParser
     {
+        static readonly ParameterExpression CtxParam = Expression.Parameter(typeof(Context), "ctx");
+
         static Parser<ExpressionType> Operator(string op, ExpressionType opType)
         {
             return Parse.String(op).Token().Return(opType);
@@ -46,7 +48,7 @@ namespace XNeedle.Parser
             var ctxMethodInfo = typeof(ContextFunctions).GetTypeInfo().GetMethod(name, parameters.Select(e => e.Type).Prepend(typeof(Context)).ToArray());
             if (ctxMethodInfo != null)
             {
-                return Expression.Call(ctxMethodInfo, parameters.Prepend(Expression.Constant(ctx)).ToArray());
+                return Expression.Call(ctxMethodInfo, parameters.Prepend(CtxParam).ToArray());
             }
 
             throw new ParseException(string.Format("Function '{0}({1})' does not exist.", name,
@@ -114,7 +116,13 @@ namespace XNeedle.Parser
 
         static Parser<ExpressionPart> ExprPart(Context ctx)
         {
-            return Expr(ctx).Select(body => new ExpressionPart{Expr = Expression.Lambda<Func<string>>(body)});
+            return Expr(ctx).Select(body =>
+            {
+                Expression stringBody = body.Type == typeof(string)
+                    ? body
+                    : Expression.Call(body, typeof(object).GetMethod("ToString", Type.EmptyTypes)!);
+                return new ExpressionPart { Expr = Expression.Lambda<Func<Context, string>>(stringBody, CtxParam) };
+            });
         }
 
         static readonly Parser<string> XPath =

Transformation/ContextFunctions.cs

@@ -1,7 +1,4 @@
 using System;
-using System.IO;
-using System.Text;
-using System.Xml;
 using Sprache;
 using XNeedle.Parser;
 using XNeedle.Parser.Elements;
@@ -16,13 +13,12 @@ namespace XNeedle.Transformation
             return $"#x{v:X8}";
         }
 
-        public static int GetLevel(XmlNode node)
+        public static double GetLevel(Context ctx)
         {
             int level = 0;
-            XmlNode? currentNode = node;
-            while (null != (currentNode = currentNode.ParentNode))
+            System.Xml.Linq.XElement? n = ctx.Node;
+            while (null != (n = n?.Parent))
                 level++;
-
             return level;
         }
         public static double crc(Context ctx)
@@ -51,7 +47,7 @@ namespace XNeedle.Transformation
 
         public static string attr(Context ctx, string name, string value)
         {
-            if (ctx.Node is null || !ctx.Node.HasAttributes) return "";
+            if (ctx.Node is null) return "";
             var attr = ctx.Node.Attribute(name);
             if (attr != null)
             {