mother

In the culinary world, “mother” is a natural complex of bacteria, proteins, enzymes and fiber, which controls the fermentation of vinegar. It has this property, that the mother derived in a new batch of vinegar can subsequently be used to start the fermentation of yet another batch.

This gem proposes a similar arrangement, wherein a hash-like map or object comprises the un-fermented source, while Mother (the ruby gem) provides a “fermented” abstraction which 1) provides convenient access to the hash’s properties, and 2) generates a new Mother for any accessed property which is, itself, another hash, so that hashes of hashes, once mothered, will yield children who are also mothers.

Installation

Add this line to your application’s Gemfile:

gem 'mother'

And then execute:

$ bundle

Or install it yourself as:

$ gem install mother

See? Not so bad.

Usage

Mother is easy to use. If you have a hash like so:

source = {
  favorite_beverage: 'Chamomile Tea'
}

Then create a Mother like so:

mom = Mother.create source

And then you can call your mom (and you should!):

mom.favorite_beverage #=> 'Chamomile Tea'

Mother from another resource

Mothers can create from hashes, but also from two popular hash-like file types, namely YAML and JSON. These things will work (assuming the files actually exist):

mom = Mother.create 'math/theorems.yml'
mom = Mother.create './space_program.yaml'
mom = Mother.create '/opt/var/kids/birthdays.json'

My what big hashes you have!

As mentioned earlier, Mothers can be grandmothers. Let’s expand our earlier hash:

source = {
  daughter: {
    favorite_beverage: 'Gen Macha Tea'
  }
}

Then create a (grand)Mother just like we did before:

mom = Mother.create source

And then we find that the daughter is also a Mother:

mom.daughter.class #=> Mother

And indeed can be called in the same way:

mom.daughter.favorite_beverage #=> 'Gen Macha Tea'

There was an old woman who lived in a shoe…

Mothers can also have whole broods of children (in Ruby these are called arrays), any of which could be mothers:

source = {
  brood: [
    12,
    'orange',
    {
      favorite_band: 'BTS'
    }
  ]
}

We create the mother as usual:

mom = Mother.create source

And then we find that we can access the array of children:

mom.brood.first              #=> 12
mom.brood[1]                 #=> 'orange'
mom.brood.last.class         #=> Mother
mom.brood.last.favorite_band #=> 'BTS'

What About Demeter

At this point, I’d like to give a cheery halo to Demeter, the Greek mother goddess of harvest, grain, and Persephone. You may be familiar with the programming principle to which she has lent her name, namely the Law of Demeter, also known as the Principle of Least Knowledge. According to this sage law, don’t do this:

thing_1.thing_2.thing_that_thing_2_can_do(plenty, of: arguments)

All those dots mean that our code, rather than just contenting itself with knowning how to use thing_1, must also be inculcated with the proper use of thing_2. Bleh!

Law of Demeter violations are Bad ™, and you’ll die if you use ‘em. But in this case, let’s relax our customary parsimony and play around with them a bit!

I propose some guidelines:

to keep things easy to reason about, consider not mutating your motherized hashes. Just treat them like facts which don’t change.
avoid accessing them very deeply in any given context. Instead of calling the daughter from the mother, and daisy-chaining calls to the daughter’s attributes, instead hand the daughter to another object, which can then access the daughter’s attributes.
don’t worry so much.

The use case for which I dreamed this gem up was that I wanted to collect all my magical values for a 2D game into a single YAML config file, and then be able to easily distribute the subsections to various objects within the game, and to provide easy, method-like access to all the properties (like they get to do with objects in JavaScript).

Development

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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/joelhelbling/mother. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

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

Dedication

I’d like to dedicate this gem to my Mom, who taught me to think analytically, who was my first and best math teacher, and who encourages me to do my best, even nowadays. I love you, Mom.