Weighable

A gem for dealing with weights in ruby and rails.

Installation

Add this line to your application's Gemfile:

gem 'weighable'

And then execute:

$ bundle

Or install it yourself as:

$ gem install weighable

Usage

Using the weight class is as simple as:

weight = Weighable::Weight.new(5, :gram)
weight = weight + Weighable::Weight.new(1, :ounce)
weight = weight.round(4)

This gets even cleaner when you include the core extensions (included by default with rails):

require 'weighable/core_ext'
weight = 5.grams
weight = weight + 1.ounce
weight = weight.round(4)

Usage with Rails

By default core extensions are included with rails. You also get some helpers to integrate weight into active record.

Add a weight attribute to a model:

class AddWeightToItem < ActiveRecord::Migration
  def change
    change_table :items do |t|
      t.weighable :my_weight
    end

    # OR

    add_weighable :items, :my_weight
  end
end

class Item < ActiveRecord::Base
  include Weighable::Model

  weighable :my_weight

  # OR require the field to be present

  weighable :my_weight, presence: true
end

# Now use it

item = Item.first
item.weight = 6.grams
item.save!
p item.weight == 6.grams # => true

Development

After checking out the repo, run bin/setup to install dependencies. 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/greenbits/weighable.

License

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