A Typed Struct is a lightweight data structure inspired by Dry Struct, which allows for reading and writing properties while making use of a flexible and powerful type checking system, which also incorporates Ruby's RBS for type definitions.
require 'typed_struct' # unless using rails
User = TypedStruct.new name: String, # an instance of String
age: Integer, # an instance of Integer
username: /\w{4,}/, # must match given Regexp
rating: (0..5), # must be value from 0 to 5
type: "User", # must by a string with value "User"
interests: Rbs("Array[String]"), # an RBS generic type (an Array of Strings)
preferences: Rbs("{ opt_out_of_emails: bool, additional: untyped }") # RBS record type
clive = User.new name: "Clive",
age: 22,
interests: %w[surfing skiing],
preferences: { opt_out_of_emails: true, additional: { preferred_theme: :dark } },
type: "User",
rating: 4,
username: "cliveabc"
clive.age # 22
clive.age = '22' # => Error
clive.preferences = { "opt_out_of_emails" => true, "additional" => nil } # error - type mismatch, not Symbol keys
clive.freeze # no more changes can be made
Note that a TypedStruct
inherits from Struct
directly, so anything from Struct
is also available in TypedStruct
- see Struct docs for more info.
See RBS reference for more info on writing RBS types
Add this line to your application's Gemfile:
gem 'typed_struct'
And then execute:
$ bundle install
Or install it yourself as:
$ gem install typed_struct
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 the created tag, and push the .gem
file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/johansenja/typed_struct.
The gem is available as open source under the terms of the MIT License.