I think it would be easier to declare that several forms like (true, false, ISO-8601 strings or decimal numbers) are "special" and if there's a string that look

I think it would be easier to declare that several forms like (true, false, ISO-8601 strings or decimal numbers) are "special" and if there's a string that looks like them it must be specifically noted as so. This complicates parsing, but feels more natural. In my understanding, most of time there's an occurence of "age=47", it actually means {"age": 47}, not {"age": "47"}. But if we'd want to represent the latter, we could easily do it with "age*=47". So it'll be something like: user:name=Bob,age=47,sex=M,dob=1956-12-05;pastimes:golf,opera,poker,rap;children:bobby:age=12,sex=M;sally:age=8,sex=F