private object Filter(object instance, PhpStack /*!*/ stack) { StringBuilder result = new StringBuilder(); Debug.Assert(stack.ArgCount >= 1, "Called by output buffering, so should be ok"); string data = PhpVariable.AsString(stack.PeekValueUnchecked(1)); stack.RemoveFrame(); // parse the text if (parser == null) { parser = new TagsUrlRewriter(this); } return(parser.ParseHtml(parserState, data)); }