Welcome to JAXN

JAXN (pronounced "Jackson") is a standard that carefully extends JSON with a few often-required additions to the data model, and with new syntax that makes it more human friendly.

❗ JAXN IS CURRENTLY WORK-IN-PROGRESS ❗

Until version 1.0 of JAXN is published, everything is considered work-in-progress, and anything might still change. Ideas, feedback and other input is welcome and appreciated. Please feel free to open an issue, or write to [email protected].

The JAXN Data Model

JAXN extends the JSON data model with the following points:

• Allows non-finite values NaN, Infinity and -Infinity for numbers.
• Adds a new primitive type for values representing binary data.

The JAXN Text Representation

JAXN text representation extends the JSON text representation with the following points:

• Comments
• Numbers
• Strings
• Binary Data
• Unquoted Object Keys
• Trailing Comma

Comments

• # single-line comment
• // single-line comment
• /* block comment */

Numbers

• Allow a leading + sign.
• Allow omission of leading or trailing zeros, e.g. .5, or 42..
• Add non-finite values NaN and Infinity.
• Add hexadecimal integer values, e.g. 0xDEADBEEF.

Strings

• Add single-quoted strings, e.g. 'This is a "single-quote" string. No really, it is!'.
• Add new escape sequences \', \v, \0 and \u{X...}.
• Add multiline strings with no escape sequences.
• Add concatenation of strings, e.g. "Hello," + " world!".

Binary Data

• New primitive type that can represent arbitrary byte sequences.
• Two syntactical variants that can be concatenated with each other.
• Hexdumped binary, e.g. $48656c6c6f2c20776f726c6421.
  • Allows optional dots, e.g. $48.65.6c.6c.6f.2c.20.77.6f.72.6c.64.21.
• Binary strings, e.g. $"Hello, \x77orld!".
  • Only printable ASCII characters allowed, no control characters.
  • No \uXXXX or \u{...} escape sequences allowed, instead:
  • Add \xXX for arbitrary byte values.

Unquoted Object Keys

• Allow unquoted object keys, e.g. { foo: "Hello", bar: 42 }.

Trailing Comma

• Allow [1,2,3,] and { foo: "Hello", bar: 42, }.

More information

• Specification
• Discussion
• ABNF grammar

Libraries implementing JAXN

• taocpp/json
• ...

Copyright (c) 2017-2018 Daniel Frey and Dr. Colin Hirsch