Dry::Types::Fear

Dry::Types integration with fear allows using Fear::Option as optional type for Dry::Types

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add dry-types-fear

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install dry-types-fear

Usage

Load the :fear_option extension in your application.

require 'dry-types'
require 'dry/types/fear'

Dry::Types.load_extensions(:fear_option)

module Types
  include Dry.Types()
end

Append .option to a Type to return a Fear::Option object:

Types::Option::Strict::Integer[nil] 
#=> Fear.none
Types::Option::Coercible::String[nil] 
#=> Fear.none
Types::Option::Strict::Integer[123] 
#=> Fear.some(123)
Types::Option::Strict::String[123]
#=> Fear.some(123)
Types::Option::Coercible::Float['12.3'] 
#=> Fear.some(12.3)

'Option' types can also accessed by calling .option on a regular type:

Types::Strict::Integer.option # equivalent to Types::Option::Strict::Integer

You can define your own optional types:

option_string = Types::Strict::String.option
option_string[nil]
# => Fear.none
option_string[nil].map(&:upcase)
# => Fear.none
option_string['something']
# => Fear.some('something')
option_string['something'].map(&:upcase)
# => Fear.some('SOMETHING')
option_string['something'].map(&:upcase).get_or_else { 'NOTHING' }
# => "SOMETHING"

You can use it with dry-struct as well:

class User < Dry::Struct
  attribute :name, Types::Coercible::String
  attribute :age,  Types::Coercible::Integer.option
end

user = User.new(name: 'Bob', age: nil)
user.name #=> "Bob"
user.age #=> Fear.none 

user = User.new(name: 'Bob', age: 42)
user.age #=> Fear.some(42) 

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 the gemspec, 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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/bolshakov/dry-types-fear.