Condensable

In chemistry, condensation is the process of vapour or gas to become a liquid. But, this is no chemistry things. Here, condensable is describing a condition of a class that allow to make itself respond to getter and setter routines when they are not (yet) defined.

Condensation works well with Assignbot!

Add this line to your application's Gemfile:

gem 'condensable'

And then execute:

$ bundle

Or install it yourself as:

$ gem install condensable

Simple enough, just include Condensable into your class and you are set.

class OrderParams
  include Condensable
end

And, you can use your condensable instance as follow:

order = OrderParams.new
order.order_id = 12
order.customer = "Adam Pahlevi Baihaqi"

Notice that both order_id and customer have not yet been defined, but a condensable class would automatically define that on-demand.

You don't need to define a class, you can generate them on-demand:

order = Condensable.new.new
order.order_id = 123

First .new will create a class on-the-fly for you. The second .new actually initialize the class.

You can also pass in block, and define what a usual class could be defined:

order = Condensable.new do
  def full_name
    "#{first_name} #{last_name}"
  end
end.new

order.first_name = 'Adam'
order.last_name = 'Pahlevi'
order.full_name == 'Adam Pahlevi' # true

For more, please have a look at our spec to demonstrate its power.

By default, when a getter is not available, a condensable instance will return nil:

order.shipping_address == nil # true

To alter the default behaviour, specify condensable default in your class, like below:

class OrderParams
  include Condensable

  condensable default: "not-available"
end

Therefore, when invoked:

order.shipping_address

It will returns not-available.

There are 4 condensation behaviours:

1. Returning nil (condensable default: nil)
2. Returning string (condensable default: "some string")
3. Executing a method, by always passing a symbol (condensable default: :execute_method)
4. Raising an error (condensable default: :raise_error)

For more details, please see the spec which demonstrates the all four.

To get to know what are all the condensed variables, use:

order.condensed_variables

To get to know all of condensed values, use:

order.condensed_values

Iterating both:

order.each do |condensed_var, condensed_value|
  puts "#{condensed_var}: #{condensed_value}"
end

order.is_condensed?(:order_id)          # ==> true
order.is_condensed?(:shipping_address)  # ==> false

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