as_range

Removes the boilerplate of working with objects representing ranges.

Instead of

class Period
  def initialize(period_start, period_end)
    @period_start = period_start
    @period_end = period_end
  end

  def as_range
    @period_start..@period_end
  end
end

With as_range, you can do:

class Period
  as_range

  def initialize(start_date, end_date)
    @start_date = start_date
    @end_date = end_date
  end
end

By default, as_range will generate a range using start_date and end_date as the bound of the range. You can customize this behavior by passing a symbol to the :start and :end options:

class Period
  attr_reader :period_start
  as_range start: :period_start, end: :compute_period_end

  def initialize(period_start)
    @period_start = period_start
  end

  def compute_period_end
    period_start + 1.year
  end
end

The :start and :end also accept a proc:

class Period
  attr_reader :period_start
  as_range start: :period_start, end: -> { period_start + 1.year }

  def initialize(period_start)
    @period_start = period_start
  end
end

By default, the generated range includes the end of the range. To exclude the end, set the include_end option to false:

class Period
  attr_reader :period_start
  as_range include_end: false

  def start_date
    Date.new(2020, 1, 1)
  end

  def end_date
    Date.new(2021, 1, 1)
  end
end
> p = Period.new
> p.as_range
# => #<Date: 2020-01-01>...#<Date: 2021-01-01> # Note the extra dot.

By default, it names the generated method as_range. To set a custom method name, use the method_name option:

class Period
  as_range method_name: :to_range

  def start_date
    Date.new(2020, 1, 1)
  end

  def end_date
    Date.new(2021, 1, 1)
  end
end

> p = Period.new
> p.to_range
# => #<Date: 2020-01-01>..#<Date: 2021-01-01> # Note the extra dot.

By default, as_range will add methods to every class and module.

This is not ideal if you're using as_range in a library: those who depend on your library will get those methods as well.

It's also not obvious where the methods come from. You can be more explicit about it, and restrict where the methods are added, like this:

require "as_range/explicit"

class MyPeriod
  extend AsRange.explicit

  as_range method_name: :now_this_class_can_use_as_range
end

Crucially, you need to require "as_range/explicit" instead of require "as_range". Some frameworks, like Ruby on Rails, may automatically require everything in your Gemfile. You can avoid that with gem "as_range", require: "as_range/explicit".

In explicit mode, you need to call extend AsRange.explicit in every class or module that wants the as_range methods.

Add this line to your application's Gemfile:

gem 'as_range'

And then execute:

$ bundle

Or install it yourself as:

$ gem install as_range

After checking out the repo, run bin/setup to install dependencies. Then, run bin/rspec 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.

as_range's explicit mode is directly inspired by attr_extras.

Bug reports and pull requests are welcome on GitHub at https://github.com/aliou/as_range

MIT