Resultt

A simple library to wrap execution result in smart success or error objects.

success_result = Result do
  1 + 1
end
# => #<Resultt::Success:0x0000000098c718 @value=2>

success_result.success? # true
success_result.value # 2
success_result.error? # false

error_result = Result do
  raise StandardError, 'error result'
end
# => #<Resultt::Error:0x000000007c5498 @error=#<StandardError: error result>>

error_result.error? # true
error_result.error # #<StandardError: error result>

result = Result do
  # do something
end

case result
when Resultt::Success then 'it is a success!'
when Resultt::Error then 'oh no! error!'
end

Installation

Add this line to your application's Gemfile:

gem 'resultt'

And then execute:

$ bundle

Or install it yourself as:

$ gem install resultt

Usage

extend Resultt in your class and you're good to go!

class MyClass
  extend Resultt

  def foo
    Result do
      # do something
    end
  end
end

`map` and `map_error`

it is possible to map on values and errors in Resultt objects using map and map_error respectively:

result = Result { 1 + 1 }
# => #<Resultt::Success:0x000000007502d8 @value=2>
mapped_result = result.map { |value| value + 1 }
# => #<Resultt::Success:0x000000007502d8 @value=3>

result = Result { raise StandardError, 'error' }
# => #<Resultt::Error:0x00000000bc8d88 @error=#<StandardError: error>>
mapped_result = result.map_error { |error| error.class.to_s }
# => #<Resultt::Error:0x00000000be6568 @error="StandardError">

`Success` and `Error`

it is also possible to wrap values or errors in Resultt::Success or Resultt::Error objects directly:

Success('ok')
# => #<Resultt::Success:0x0000000076b718 @value="ok">
Error('err')
# => #<Resultt::Error:0x00000000764a08 @error="err">

Nil values

Result will return Resultt::NilValueError if the block passed to it evaluates to nil. This is to avoid having success results with nil values.

Result do
  nil
end
# => #<Resultt::Error:0x00000000afa000 @error=#<Resultt::NilValueError: Result returned a nil value>>

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/amrrbakry/resultt. 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.

Code of Conduct

Everyone interacting in the Resultt project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

amrrbakry/resultt