This is an attempt to solve the given imaginary problem.
We're building this command-line calculator for people who are comfortable with UNIX-like CLI utilities. We are starting with the basic 4 operators now but will want to eventually implement other operators and an alternate interface (such as WebSocket, file, or TCP socket). There's no need to implement these, but design with these future changes in mind.
- The calculator should use standard input and standard output
- It should implement the four standard arithmetic operators
- The calculator should handle errors and recover gracefully
- The calculator should exit when it receives a
qcommand or an end of input indicator (EOF / Ctrl+D)
Add this line to your application's Gemfile:
gem 'awesome_rpn_calculator'And then execute:
$ bundle
Or install it yourself as:
$ gem install awesome_rpn_calculator
The reason why i chose to go with gem was basically for nicety of an easy installation for whoever is trying to make use of our RPN calculator. Not to menstion that fact that it can be also used alongside in another app as a new dependency. I have tried to write this test solution in way that can provide scalabiliy for new upcoming features, and to also ensure readability, by creating small classes with basic responsabilities. That way, it can follow a more smoothly onboarding process.
This gems is using the follwing gems for self support:
- bundler (our default dependency manager)
- pry (for testing purposes only)
- simplecov (for increase/ensure test coverage)
- rake (for creating our custom rake tasks)
- reek (for adding nice linting for code smells)
- rspec (our BDD testing gem)
- rubocop (same as reek, but for more general syntax rules)
To run our AwesomeRPNCalculator, just use install the gem, and run:
$ awesome_rpn_calculator
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.
Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/awesome_rpn_calculator. 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.
The gem is available as open source under the terms of the MIT License.
Everyone interacting in the AwesomeRPNCalculator project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.