CPON - ChainPack Object Notation

CPON is inspired by JSON. It is used for data dumping as well as user input.

CPON text should be encoded in UTF-8.

CPON supports C style comments and thus /* foo */ is just simply ignored and considered as a white space character.

RPC Value types are encoded in the following way:

Null

Represented with plain null (compatible with JSON).

Bool

Represented with either true or false (compatible with JSON).

Int

Represented as number just like in JSON (e.g. 123, -42) with additional support for common hexadecimal (e.g. 0x20) and binary representation (e.g. 0b1001).

Tools generating CPON should prefer plain number representation (thus compatible with JSON).

UInt

Represented as Int with suffix u (e.g. 123u, 0x20u, 0b1001u).

Double

Represented in scientific notation with P (or p) between significant and exponent represented as Int (e.g. 1.25p-2, -0.0625p3, 0b1001p+2).

Tools generating CPON should prefer format [-]0xh.hhhp[+|-]dd, thus significant is normalized hexadecimal number and exponent is decimal.

Decimal

Represented in scientific notation (both E and e can be used) from significant and exponent Int number, or as decimal number with decimal point (.) (e.g. 123.45, 1.2345e2, 12345E-0x2).

Tools generating CPON should prefer scientific notation with e where both significant and exponent is decimal and optionally representation with decimal point if number of inserted zeroes would be small enough.

Blob

Represented as String with b prefix where values from 0x00 to 0x1f and from 0x7f to 0xff are represented as escape sequences \hh (where hh is character's hexadecimal numeric value) with these exceptions:

Example: b"ab\31"

Tools generating CPON should prefer special escape sequences over hexadecimal numeric ones.

HexBlob

This is CPON extension on Blob type. There is no such alternative in ChainPack.

Blob is represented as series of hexadecimal numeric values in String like syntax with x prefix.

Example: x"616231"

Tools generating CPON are discouraged from using this type.

String

Represented as series of characters wrapped in ". It can contain any characters except of the following ones that are mapped to these escape sequences:

Octal, hexadecimal and Unicode escape sequences are not support (this is incompatibility with JSON).

Example: "some\tstring"

DateTime

Represented as String with d prefix where string's value is date, time and optional time zone in ISO-8601 format (e.g. d"2017-05-03T15:52:31.123")

List

Represented as sequence of other RPC values wrapped in []. Th sequence is delimited by comma (,). The additional comma is allowed after last item (JSON incompatible).

Examples: [1 2 3], [1,2,3,]

Map

Represented as pairs of String key and RPC value delimited by colon (:). All pairs are wrapped in {} and delimited by comma (,). Contrary to JSON's objects comma after last pair is allowed.

Examples: {"one": 1, "dec": 1.22,}

IMap

Reprensented as pairs of Int key and RPC value delimited by colon (:). All pairs are wrapped in {} and delimited by comma (,). Contrary to JSON's object comma after past pair is allowed.

Examples: {1: "one", 2: b"foo",}

MetaMap

Represented as pairs of String or Int key and RPC value delimited by color (:). All pairs are wrapped in <> and delimited by comma (,). Comma after past pair is allowed. MetaMap can't be alone, it must be followed by some other RPC value (that is not MetaMap).

Example: <1: "foo", "date": d"2017-05-03T15:52:31.123">42

Syntax highlighting support

Syntax definition for tree sitter can be found at https://github.com/amaanq/tree-sitter-cpon