@@ -108,8 +108,12 @@
 }
 
 Value lift(in LexPosition pos, Value v, Layer lay, Table callerCtx)
 {
+	// functions are automatically lifterd
+	if( cast(FunValue) v )
+		return v;
+	
 	// similar to invoke Function, but with only one argument bound to ValueLayer
 	Value _f = callerCtx.get(lay, SystemLayer, pos);
 	if(auto f = cast(FunValue)_f)
 	{
@@ -154,13 +158,12 @@
 		(VarExpression e)
 		{
 			if( lay == ValueLayer )
 				return ctx.get(e.name, lay, e.pos);
-			try {
+			if( ctx.has(e.name, lay, e.pos) )
 				return ctx.get(e.name, lay, e.pos);
-			} catch( Throwable ) { // [TODO] more precise...
+			else
 				return lift(e.pos, ctx.get(e.name, ValueLayer, e.pos), lay, ctx);
-			}
 		},
 		(LayExpression e)
 		{
 			if( e.layer == MacroLayer )
@@ -183,13 +186,8 @@
 			return invokeFunction(e.pos, eval(e.fun, ctx, true, lay), e.args, ctx, lay);
 		},
 		(FunLiteral e)
 		{
-			Value[Value[]][Layer] memo;
-			AST macroMemo = null; // cache
-
-			// funvalue need not be rised
-			// no, need to be rised !!  suppose @t(fib)("int")
 			return new UserDefinedFunValue(e, ctx);
 		},
 		delegate Value (AST e)
 		{
@@ -240,11 +238,11 @@
 			return t;
 		},
 		(VarExpression e)
 		{
-			try {
+			if( ctx.has(e.name, MacroLayer, e.pos) )
 				return ctx.get(e.name, MacroLayer, e.pos);
-			} catch( Throwable ) {// [TODO] more precies...
+			else {
 				Table t = new Table;
 				t.set("pos",  theLayer, pos);
 				t.set("is",   theLayer, new StrValue("var"));
 				t.set("name", theLayer, new StrValue(e.name));