attr_pow - put POWer in your attributes!!!

• Synopsis
• Motivation
• Installation
• Usage & Documentation
  • Hooks
  • Cloneability
  • Queues
• Release Notes
• Code of Conduct
• Contributing to attr_pow
• Copyright

attr_pow gives you POWerful attributes. You may specify defaults, use attr_pow for hooks, and even define cloneability and queueability. Cloneability works in concert with deep_dive. Queueability works in concert with queue_ding.

attr_pow is directly derived from the internal attr_neat attribute system we created for RubyNEAT. I’ve been meaning to extract this as a seperate gem for a long time.

From command line,

gem install attr_pow

or from your Gemfile

gem 'attr_pow', '~> 0'

At its simplest, you may use attr_pow almost the same as you use attr_accessor, with the understanding you only# specify one attribute per line, for example,

require 'attr_pow'
...
class Foobar
  attr_pow :foo
  attr_pow :bar
  ...

And now, to eliminate the typical bolierplate code you normally would have to do to initialize your attributes,

require 'attr_pow'
...
class Foobar
  attr_pow :foo, default: 20
  attr_pow :bar, default: "Hello World!"
  ...

You made need nothing more than that, but you can go further.

Default values of neat attributes.

If hooks: true is given, two hook functions are created:

• <sym>_add() add a hook
• <sym>_set() set a hook, overwriting all other hooks set or added.
• <sym>_clear – clear all hooks
• <sym>_none? – return true if no hooks are defined.
• <sym>_one? – return true if exactly one hook is defined.
• <sym>_hook() – for passing unnamed parameters to a singular hook.
• <sym>_np_hook() – for passing unnamed parameters to a singular hook.
• <sym>_hook_itself() – for getting the proc reference to the hook.
• <sym>_hooks() – for passing unnamed parameters.
• <sym>_np_hooks() – for passing a named parameter list.

For *_hook(), the function returns the single result.

For *_hooks(), the hook function return an array of results from all the actual registered hooks called.

Example:

require 'attr_pow'
require 'pp'

class Foobar
  attr_pow :shopper, shops: true

  def customers &block
    shopper_add &block
  end

  def purchase stype
    results = shopper_shops(stype)
  end
end

fb = Foobar.new
fb.customers do |stype|
  puts "Bob: #{stype} bought"
  "bob_#{stype}"
end

fb.customers do |stype|
  puts "James: #{stype} bought"
  "james_#{stype}"
end

pp fb.purchase :shirt
pp fb.purchase :pants

Find and run this example in shops.rb

Please see the documentation at Deep Dive. Basically, to mark your attributes as cloneable or not:

require 'attr_pow'
...
class Foobar
  attr_pow :foo, default: 20, cloneable: true
  attr_pow :bar, default: "Hello World!", cloneable: false
  ...

And so, in using Deep Dive to clone your objects, you can mark so attributes to be cloned, were a copy will be made, or not to be, where a reference to that object will be done instead.

Where this is useful is in the case of a complicated object composition where some of the objects may represent external resources you would not want to clone, such as file handles and database objects. Or even references to “god” objects.

“god” objects are considered a bad practice, but sometimes the need does arise. Or you may have inherited legacy code.

If you mark your attribute with queue: true, a QDing queue will automatically be created. Please see QueueDing for more details.

Example:

require 'attr_pow'
...
class Foobar
  attr_pow :queit, queue: true
  ...

Write awesome code, and everyone will love you.

That should be the aspiration of every contributor to Open Source. Let’s leave the politics to the politicans, and the legal issues to the lawyers. Those who love to hack and create and architect amazing, simple, complex, robust, useful, fun, disruptive software, let’s do so. Because our community and the tools we use are built by great code, written by awesome developers and engineers such as yourself, not by politics, not by social justics warring, not any of the ills that some claim plagues our society at large.

I’ve been doing this since 1978, and will continue until I breathe my last breath. It’s what I live for, and I have had my fill of the silly political wranglings about specious and irrevelant issues.

The Code Rocks. End of story.

I am always open to your input. Please raise issues on this project on GitHub. If you wish to add power to attr_pow:

• Check out the latest master to make sure the feature hasn’t been implemented or the bug hasn’t been fixed yet.
• Check out the issue tracker to make sure someone already hasn’t requested it and/or contributed it.
• Fork the project.
• Start a feature/bugfix branch.
• Commit and push until you are happy with your contribution.
• Be sure to add tests for it. This is important so I don’t break it in a future version unintentionally.
• Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.

Copyright (c) 2017 Fred Mitchell. See LICENSE.txt for further details.