Greedy::DCI

A Toolkit for rapid prototyping of interactors, use cases and service objects, using the DCI paradigm.

WARNING! This implementation will blow the method cache, slow down performance and consume excessive resources (hence the name), therefore production usage is seriously discouraged. Instead, use of a Wrapper Based alternative is highly recommended.

What is DCI?

DCI (Data, context and interaction) is a new Role-Based Paradigm for specifying collaborating objects. Trygve Reenskaug is the originator best known for formulating the MVC (model–view–controller) pattern.

You can read more about DCI at the following links:

• http://dci.github.io/
• http://dci-in-ruby.info/
• http://fulloo.info/

Installation

Add this line to your application's Gemfile:

gem 'greedy-dci'

And then execute:

$ bundle

Or install it yourself as:

$ gem install greedy-dci

Usage

require 'greedy/dci'

# Data

Purchase = Struct.new(:toy, :buyer)
Deliver = Struct.new(:toy, :recipient, :purchase, :status)

# Behaviors

module Buyer
  def buy(toy)
    Purchase.new toy, self
  end
end

module Recipient
  def receive(purchased)
    Deliver.new purchased.toy, self, purchased, :pending
  end
end

# Contexts

PurchaseToy = Greedy.context { |purchaser|
                                using purchaser.as Buyer
                                using purchaser.as Recipient

                                def call(toy)
                                  purchased = purchaser.buy toy
                                  purchaser.receive purchased
                                end
                              }


GiftToy = Greedy.context { |gifter, giftee|
                            using gifter.as Buyer
                            using giftee.as Recipient

                            def call(toy)
                              gift = gifter.buy toy
                              giftee.receive gift
                            end
                          }

# Interactions

finn_purchase_toy = PurchaseToy[purchaser: 'Finn']
finn_purchase_toy.call 'Rusty sword'
finn_purchase_toy.('Armor of Zeldron')
finn_purchase_toy['The Enchiridion']

['Card Wars', 'Ice Ninja Manual', 'Bacon'].each &GiftToy[gifter: 'Jake', giftee: 'Finn']

View more examples

Context methods

to_proc

Returns call method as a Proc.

['Card Wars', 'Ice Ninja Manual', 'Bacon'].map &GiftToy[gifter: 'Jake', giftee: 'Finn']

context[params,...]

Square brackets are alias for call method.

TransferMoney[from: source_account, to: destination_account][amount: 100]

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/RichOrElse/greedy-dci.

License

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