seagreen/Son

A subset of JSON.

JSON contains redundant syntax such as allowing both 10e2 and 10E2. This helps when writing it by hand but isn't good for machine-to-machine communication. Piping JSON through multiple programs creates lots of trivial changes, which makes it hard to do things like take meaningful diffs.

Son is a subset of JSON without redundant options. It's intended for machine-to-machine communication by programs that want to follow Postel's Law -- they can accept normal JSON for flexibility and output Son for consistency.

Son Numbers

• No exponential notation
• No trailing zeros in fractions
• No negative zero
• No positive sign

positiveInteger:

fraction:

Son Strings

• No unnecessary escape sequences

JSON doesn't allow Unicode characters below codepoint x20 or unescaped " and \ in strings. To allow these to still be encoded in JSON we've had to keep a few escape sequences. We use two-character escape sequences (e.g. \n) when available, and six-character ones (e.g. \u0001) when not.

shortcutEscape:

Other Changes from JSON

• No insignificant whitespace

Status

Unreleased. Like JSON, the intention is that once Son is released it will never change.

Specification

The formal part of its specification is ./son.ebnf. It uses the EBNF notation described here.

Additionally:

• The only valid byte encoding of Son is UTF-8. Byte order marks are forbidden.

• Object keys must be unique.

• Object members must be sorted by ascending lexicographic order of their keys.

Implementations

• Haskell reference implementation: ./implementation.

Special Thanks

• @chmike and @etherealvisage: key ordering should specify "ascending".

• @John-Nagle: UTF-8 should be the only allowed encoding.

Differences between this and related projects

See here.

Notes

• The diagrams were generated with GrammKit.

• ./vendored/rfc7159.txt is from here.