You may not leave JSON object properties unquoted, so it'd have to read: {"object": [ {"id": "1234"}, {"isEnabled": "true"}, {"props": ["

You may not leave JSON object properties unquoted, so it'd have to read: {"object": [ {"id": "1234"}, {"isEnabled": "true"}, {"props": ["abc", "123", "false"]}]} So you have extraneous quotes, extraneous semicolons, extraneous commas, plus the parsing code is complicated by having to handle all of that rather than atoms & lists (that's not a strong reason, since parsing code is written once and used millions of times). I really, really don't get the visceral opposition to S-expressions. From my perspective they're both better & simpler.