spec.txt

                                 Canonical JSON

1. Introduction

  Canonical JSON is a variant of JSON in which values each have a single,
  unambiguous serialized form. This provides meaningful and repeatable hashes
  of encoded data. Canonical JSON can be parsed by regular JSON parsers provided
  that no control characters appear in strings.

2. Differences from JSON

  - Whitespace between tokens is disallowed. Leading and trailing whitespace
    is likewise disallowed.
  - Floating point numbers, exponents and "minus zero" are all disallowed.
  - Object keys must appear in lexiographical order and must not be repeated.
  - Strings are uninterpreted bytes, with the only escaped byte values being
    backslash and quote. Escaping is mandatory for those two characters.
  - String contents are not guaranteed be parsable as UTF-8. Be aware that
    encoded data may contain embedded control characters and nulls.

3. Example

  JSON:

    {
      "foo": "bar",
      "abc": 9e3,
      "snowman": "\u2603",
      "zoo":
        [
          "zorilla",
          "anteater"
        ]
    }

  Canonical JSON:

    {"abc":9000,"foo":"bar","snowman":"☃","zoo":["zorilla","anteater"]}

4. Grammar

  value:
    object
    array
    string
    number
    true
    false
    null

  object:
    {}
    { members }

  members:
    pair
    pair , members

  pair:
    string : value

  array:
    []
    [ elements ]

  elements:
    value
    value , elements

  string:
    ""
    " chars "

  chars:
    char
    char chars

  char:
    any byte except hex 22 (") or hex 5C (\)
    \\
    \"

  number:
    int

  int:
    digit
    digit1-9 digits
    - digit1-9
    - digit1-9 digits

  digits:
    digit
    digit digits

5. References

  Spec derived from: http://wiki.laptop.org/go/Canonical_JSON