Exactly. I was referring to the grammar the tokenizer uses for tokenizing numbers. Instead of faithfully copying the JSON spec, you could use a simpler rule tha

Exactly. I was referring to the grammar the tokenizer uses for tokenizing numbers. Instead of faithfully copying the JSON spec, you could use a simpler rule that also accepts leading zeros. As for the leading "-", in languages that have expressions it is common to parse the "-" as a prefix operator because that covers both negative numbers (-1.0) and negating variables (-x). But in JSON there are no expressions like 1.0-2.0 so the leading "-" is parsed as part of the number.