DataObject

A simple, immutable data wrapper.

Overview

This gem provides one class: DataObject. This class is very similar to a Struct, with two notable differences:

1. A DataObject is immutable and may not be altered after it has been created.
2. Classes that inherit from DataObject will require all known properties to be set when instances of such classes are initialized.

Usage

A DataObject can be used much like Struct from the ruby standard library.

coordinate = DataObject.new(x: 1, y: 2, z: 3) # => <DataObject x=1 y=3 z=3>

A DataObject has attribute readers.

coordinate.x # => 1
coordinate.y # => 2
coordinate.z # => 3

A DataObject may also be coerced into an Array or a Hash.

coordinate.to_a # => [[:x, 1], [:y, 2], [:z, 3]]
coordinate.to_h # => {:a=>1, :b=>2}

A DataObject is enumerable.

coordinates.map { |name, value| value } # => [1,2,3]

Your own data objects

You can make your own named DataObject classes.

Classes you create this way will have all the same properties a standard data object does. Additionally, descendants of a data object will ensure all known attributes are defined during initialization.

Coordinate = DataObject.new(:x, :y, :z)
Coordinate.new(x: 1, z: 3) # => ArgumentError: missing keyword: y
coordinate = Coordinate.new(x: 1, y: 2, z: 3) # => <Coordinate x=1 y=2 z=3>

Installation

Add this line to your application's Gemfile:

gem 'data_object'

And then execute:

bundle

Or install it yourself with RubyGems:

gem install data_object

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/damien/data_object. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.