@@ -78,14 +78,13 @@
 
 class Table : Value
 {
 	enum Kind {PropagateSet, NotPropagateSet};
-	bool kill = false; // to refactor
 
 	this( Table proto=null, Kind k = Kind.PropagateSet )
 		{ this.prototype = proto; this.kind = k; }
 
-	void set(string i, Layer lay, Value v, LexPosition pos=null)
+	void set(string i, Layer lay, Value v)
 	{
 		if( setIfExist(i, lay, v) )
 			return;
 		data[i][lay] = v;
@@ -92,15 +91,10 @@
 	}
 
 	bool has(string i, Layer lay) const
 	{
-		if( i in data ) {
-			if( lay !in data[i] )
-				return false;
-			if(kill)
-				return false;
-			return true;
-		}
+		if( i in data )
+			return !!(lay in data[i]);
 		if( prototype is null )
 			return false;
 		return prototype.has(i, lay);
 	}
@@ -109,15 +103,13 @@
 	{
 		if( i in data ) {
 			// [TODO] consider forwarding to proto also in this case
 			if( lay !in data[i] )
-				throw genex!RuntimeException(pos, sprintf!"'%s' is not set in layer %s"(i,lay));
-			if(kill)
-				throw genex!RuntimeException(pos, sprintf!"'%s' is killed in macro"(i));
+				throw genex!RuntimeException(pos, sprintf!"'%s' is not set in %s layer"(i,lay));
 			return data[i][lay];
 		}
 		if( prototype is null )
-			throw new RuntimeException(pos, sprintf!"'%s' not found"(i));
+			throw genex!RuntimeException(pos, sprintf!"'%s' not found in %s layer"(i,lay));
 		return prototype.get(i, lay, pos);
 	}
 
 	T access(T,S...)( Layer lay, string path, S rest )
@@ -157,13 +149,52 @@
 			result ~= prototype.toStringWithoutParen();
 		}
 		return result;
 	}
-	
-	string toString() const
+
+	string toString()
 	{
+		if( isList() )
+			return text(toList());
 		return "{" ~ toStringWithoutParen() ~ "}";
 	}
+
+public:
+	/// Is this an empty table?
+	bool empty()
+	{
+		return data.length==0 && (prototype is null || prototype.empty);
+	}
+	
+	/// Can be seen as a cons-list?
+	bool isList()
+	{
+		Table t = this;
+		while(t.has("car", ValueLayer) && t.has("cdr", ValueLayer))
+			if(auto tt = cast(Table)t.get("cdr", ValueLayer))
+				t = tt;
+			else
+				return false;
+		return t.empty;
+	}
+
+	/// Regard table as a cons-list and convert to an array
+	Value[] toList()
+	{
+		Value[] result;
+		Table t = this;
+		while(t.has("car", ValueLayer) && t.has("cdr", ValueLayer))
+		{
+			result ~= t.get("car", ValueLayer);
+			if(auto tt = cast(Table)t.get("cdr", ValueLayer))
+				t = tt;
+			else
+				throw genex!RuntimeException("this table is not a cons-list");
+		}
+		if( t.empty )
+			return result;
+		throw genex!RuntimeException("this table is not a cons-list");
+	}	
 
 private:
 	Table                prototype;
 	Kind                 kind;
@@ -188,35 +219,35 @@
 	Table c01 = new Table(c0, Table.Kind.NotPropagateSet);
 	Table c012 = new Table(c01, Table.Kind.PropagateSet);
 	Table c013 = new Table(c01, Table.Kind.PropagateSet);
 
-	assert_nothrow( c012.set("x", ValueLayer, new IntValue(BigInt(12))) );
+	assert_nothrow( c012.set("x", ValueLayer, new IntValue(12)) );
 	assert_throw!RuntimeException( c013.get("x", ValueLayer) );
-	assert_nothrow( c013.set("x", ValueLayer, new IntValue(BigInt(13))) );
-	assert_eq( c013.get("x", ValueLayer), new IntValue(BigInt(13)) );
-	assert_eq( c012.get("x", ValueLayer), new IntValue(BigInt(12)) );
+	assert_nothrow( c013.set("x", ValueLayer, new IntValue(13)) );
+	assert_eq( c013.get("x", ValueLayer), new IntValue(13) );
+	assert_eq( c012.get("x", ValueLayer), new IntValue(12) );
 	assert_throw!RuntimeException( c01.get("x", ValueLayer) );
 
-	assert_nothrow( c01.set("y", ValueLayer, new IntValue(BigInt(1))) );
-	assert_eq( c013.get("y", ValueLayer), new IntValue(BigInt(1)) );
-	assert_eq( c012.get("y", ValueLayer), new IntValue(BigInt(1)) );
-	assert_eq( c01.get("y", ValueLayer), new IntValue(BigInt(1)) );
+	assert_nothrow( c01.set("y", ValueLayer, new IntValue(1)) );
+	assert_eq( c013.get("y", ValueLayer), new IntValue(1) );
+	assert_eq( c012.get("y", ValueLayer), new IntValue(1) );
+	assert_eq( c01.get("y", ValueLayer), new IntValue(1) );
+
+	assert_nothrow( c0.set("z", ValueLayer, new IntValue(0)) );
+	assert_eq( c013.get("z", ValueLayer), new IntValue(0) );
+	assert_eq( c012.get("z", ValueLayer), new IntValue(0) );
+	assert_eq( c01.get("z", ValueLayer), new IntValue(0) );
+	assert_eq( c0.get("z", ValueLayer), new IntValue(0) );
 
-	assert_nothrow( c0.set("z", ValueLayer, new IntValue(BigInt(0))) );
-	assert_eq( c013.get("z", ValueLayer), new IntValue(BigInt(0)) );
-	assert_eq( c012.get("z", ValueLayer), new IntValue(BigInt(0)) );
-	assert_eq( c01.get("z", ValueLayer), new IntValue(BigInt(0)) );
-	assert_eq( c0.get("z", ValueLayer), new IntValue(BigInt(0)) );
+	assert_nothrow( c012.set("y", ValueLayer, new IntValue(444)) );
+	assert_eq( c013.get("y", ValueLayer), new IntValue(444) );
+	assert_eq( c012.get("y", ValueLayer), new IntValue(444) );
+	assert_eq( c01.get("y", ValueLayer), new IntValue(444) );
 
-	assert_nothrow( c012.set("y", ValueLayer, new IntValue(BigInt(444))) );
-	assert_eq( c013.get("y", ValueLayer), new IntValue(BigInt(444)) );
-	assert_eq( c012.get("y", ValueLayer), new IntValue(BigInt(444)) );
-	assert_eq( c01.get("y", ValueLayer), new IntValue(BigInt(444)) );
-
-	assert_nothrow( c012.set("z", ValueLayer, new IntValue(BigInt(555))) );
-	assert_eq( c013.get("z", ValueLayer), new IntValue(BigInt(0)) );
-	assert_eq( c012.get("z", ValueLayer), new IntValue(BigInt(555)) );
-	assert_eq( c01.get("z", ValueLayer), new IntValue(BigInt(0)) );
-	assert_eq( c0.get("z", ValueLayer), new IntValue(BigInt(0)) );
+	assert_nothrow( c012.set("z", ValueLayer, new IntValue(555)) );
+	assert_eq( c013.get("z", ValueLayer), new IntValue(0) );
+	assert_eq( c012.get("z", ValueLayer), new IntValue(555) );
+	assert_eq( c01.get("z", ValueLayer), new IntValue(0) );
+	assert_eq( c0.get("z", ValueLayer), new IntValue(0) );
 
 	// [TODO] define the semantics and test @layers
 }