private bool ParseParenExpression(ref ASTNode node) { tokenStream.Save(); TokenStream subStream = tokenStream.AdvanceAndGetSubStreamBetween(ExpressionTokenType.ParenOpen, ExpressionTokenType.ParenClose); if (!subStream.HasMoreTokens) { tokenStream.Restore(); return(false); } ASTNode expression = ExpressionParser.Parse(subStream); if (expression == null) { tokenStream.Restore(); return(false); } node = expression; return(true); }