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Build Status Code Climate Test Coverage Dependency Status Gem Version MIT License

SwiftyEnum

SwiftyEnum enable defining enums in Ruby. Enums behave like Swift enums.

Installation

Add this line to your application's Gemfile:

gem 'swifty_enum'

And then execute:

$ bundle

Or install it yourself as:

$ gem install swifty_enum

Usage

# Define enum class.
class Flag

  # Required: Include SwiftyEnum module.
  include SwiftyEnum

  # Now you can define enum case by 'def_case' statement.
  #   Usage: def_case CASE_NAME [RAWVALUE]
  def_case :On, '1'
  def_case :Off, '0'

  # You can define method for each enum cases by 'def_method' statement.
  # Please put this statement below all of 'def_case' statements.
  #   Usage: def_method METHOD_NAME { || ... }
  def_method :status do |enum_case|
    case enum_case
    when On then
      # You can't use return statement, but value of last statement is returned from enum method.
      'OK'
    when Off then
      'NG'
    end
  end
end


# Enum case is defined as subclass.
Flag::On                       # => Flag::On

# Enum case has class method 'hashvalue'.
# It is incremental value by enum case definition.
Flag::On.hashvalue             # => 0

# Enum case has class method 'rawvalue'.
# If rawvalue is not given in definition, hashvalue is used instead.
Flag::On.rawvalue              # => '1'

# Enum case can be gotten by 'get' method with rawvalue.
Flag.get('1')                  # => Flag::On
Flag.get('0')                  # => Flag::Off

# If invalid rawvalue is given, 'get' method returns nil.
Flag.get('2')                  # => nil

# Enum case can be handled with case-when statement.
on = Flag.get('1')
case on
when Flag::Off then
  puts 'NG'
when Flag::On then
  puts 'OK'
else
  puts 'NG'
end
# >> OK

# Enum method is defined in each enum cases.
Flag::On.status                # => 'OK'
Flag::Off.status               # => 'NG'

# Arguments of enum method can be handled as variable arguments.
class Flag
  def_method :status_with do |enum_case, args|
    if args.empty?
      enum_case.status
    else
      with = args.join(', ')
      "#{enum_case.status} with #{with}"
    end
  end
end
Flag::On.status_with('foo')    # => 'OK with foo'

# When you want to get all of enum cases, use 'enum_cases'.
Flag.enum_cases                # => [Flag::On, Flag::Off]

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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/zeero/ruby-swifty_enum.

License

The gem is available as open source under the terms of the MIT License.