Errgonomic

Errgonomic provides some lightweight, opinionated ergonomics for error handling in Ruby. These semantics are a blend of Rails present? conventions, and Rust Option and Result type combinators. Without going full Option and Result. Probably.

The present_or method takes what you might ordinarily write as foo || default with a possible nil or falsey value, and brings that to any other object that may be blank?.

nil.present_or("default")
# => "default"

[].present_or(["default"])
# => ["default"]

We don't have static type checking here in Ruby, so the library is also annoyingly pedantic about matching classes for the supplied default value.

[].present_or("uh-oh")
# => Type mismatch: default value is a String but original was a Array (Errgonomic::TypeMismatchError)

When constructing that fallback object may be expensive, you can provide a block instead:

[].present_or_else { ["default"] }
# => ["default"]

And when all else fails, you can control the failure, by raising an exception for blank objects. This can be preferable to sending a blank object to some other downstream code that may be expecting a value, causing an ambiguous failure.

irb(main):007> [].present_or_raise("foo")
# => foo (Errgonomic::NotPresentError)

Installation

TODO: Replace errgonomic with your gem name right after releasing it to RubyGems.org. Please do not do it earlier due to security reasons. Alternatively, replace this section with instructions to install your gem from git if you don't plan to release to RubyGems.org.

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

bundle add errgonomic

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

gem install errgonomic

Usage

TODO: Write usage instructions here

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 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/omc/errgonomic. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the 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 Errgonomic project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.