Toon for Ruby (Token-Oriented Object Notation)

toon is a Ruby implementation of TOON (Token-Oriented Object Notation) a compact, readable, indentation-based data format designed for humans and machines.

This gem provides:

• A TOON encoder (Ruby to TOON)
• A TOON decoder (TOON to Ruby)
• A CLI (bin/toon) for converting TOON ↔ JSON
• Optional ActiveSupport integration (Object#to_toon)
• Built-in Hash#to_toon / Array#to_toon plus lightweight #to_json helpers
• Full RSpec test suite

Toon.generate({ "name" => "Alice", "age" => 30 })

Produces:

name:Alice
age:30

Toon.parse("name:Alice\nage:30")

Returns:

{ "name" => "Alice", "age" => 30 }

colors:
  [3]:
    red
    green
    blue

colors[3]:
  red
  green
  blue

Both decode correctly.

users:
  [2]{id,name}:
    1,A
    2,B

numeric fields parsed (id becomes integer)

users[2]{id,name}:
  1,Alice
  2,Bob

fields remain strings

If ActiveSupport (and by extension Rails/Active Record) is installed—regardless of whether it loads before or after toon—every object gains #to_toon.

require "toon"
require "active_support"

class User < ApplicationRecord; end

User.first.to_toon
# => "id:1\nname:Alice\n..."

• Automatically hooks in as soon as ActiveSupport finishes loading (thanks to a TracePoint watcher)
• Falls back to #as_json when present, so Active Record / ActiveModel instances serialize their attributes instead of opaque object IDs

toon now provides handy helpers even without ActiveSupport:

require "toon"

{foo: "bar"}.to_toon
# => "foo:bar"

[1, 2, 3].to_toon
# => "[3]:\n  1\n  2\n  3\n"

{foo: "bar"}.to_json
# => "{\"foo\":\"bar\"}"

Both Hash and Array gain #to_toon and #to_json implementations so you can round-trip data between TOON and JSON with a single method call.

Gem coming soon. For now:

git clone <your-repo-url>
cd toon
bundle install

Use locally:

require_relative "lib/toon"

echo '{"name":"Alice","age":30}' | bin/toon --encode

echo "name:Alice\nage:30" | bin/toon --decode

bin/toon --encode < input.json

Ensure CLI is executable:

chmod +x bin/toon

Run all tests:

bundle exec rspec

Tests include:

• Encoder specs
• Decoder specs
• CLI specs
• ActiveSupport specs

key:value

user:
  name:Alice
  age:30

colors:
  [3]:
    red
    green
    blue

Flat form:

colors[3]:
  red
  green
  blue

users:
  [2]{id,name}:
    1,A
    2,B

Flat form:

users[2]{id,name}:
  1,A
  2,B

Malformed input (e.g., missing indentation):

Malformed TOON: array header '[3]:' must be under a key (e.g., 'colors:')

Decoder stops with a friendly Toon::Error.

• Multiline values
• Quoted strings
• Mixed-type arrays
• Strict vs non-strict modes
• Streaming decoder
• Schema validation
• Ruby gem release

PRs and issues welcome!

MIT