rulebook

Allows you to define a set of 'rules' or dynamic methods to apply to a class.

Install

> gem update --system
> gem install rulebook

Simple Example

require 'rulebook'

class User
  follows_the_rules!

  def initialize(name)
    @name = name
  end

  rulebook.add /say_(.+)/ do |what_to_say|
    puts "#{@name} says '#{what_to_say.gsub(/_/, ' ')}'"
  end
end

User.new('Ryan').say_hello_world # => Ryan says 'hello world'

How It Works

TODO

Better Example

require 'rulebook'

class User
  attr :name, :title

  def initialize(name)
    @name = name
    @title = :user
  end

  rulebook.add /is_(admin|moderator|super_user|user)/ do |title|
    @title = title.to_sym
  end
end

You can now do things like

users = ['Ryan', 'Natale', 'Kasey', 'Jenna', 'Joe', 'Monica','Allan', 'Amanda']
users.collect! { |n| User.new(n) }.shuffle!

users[0].is_admin
users[1].is_moderator
users[2].is_super_user

users.each do |user|
  puts "#{user.name} is a #{user.title}"
end

Class Methods Example

require 'rulebook'

class Car
  attr :make, :model

  def initialize(make, model)
    @make, @model = make.capitalize, model.capitalize
  end

  class << self
    follows_the_rules!

    rulebook.add /new_([a-z]+)_(.+)/ do |make, model|
      new(make, model)
    end
  end
end

my_cars = [
  Car.new_honda_accord,
  Car.new_dodge_neon,
  Car.new_volkswagen_beetle
]

p my_cars.first.make # => "Honda"
p my_cars.first.model # => "Accord"

This works out if you already have ``

Now lets add some instance rules

class Car
    rule /is_(.+)\?/ do |make_or_model|
        make_or_model.capitalize!
        @make == make_or_model || @model == make_or_model
    end
end

p my_cars.first.is_honda? # => true
p my_cars.first.is_beetle? # => false

Using outside of class block

Since rule and class_rule are both class methods, you can call them all outside of a class block:

Car.rule(...){}
Car.class_rule(...){}

Since 0.2 you can call the class methods rules and class_rules to wrap your rules in a block:

Car.rules do
    rule(...){}
end

Car.class_rules do
    rule(...){}
end

The result is exactly the same. These are also callable from inside the class.

class Car
    rules do
        rule(...){}
    end
    class_rules do
        rule(...){}
    end
end

There are more examples in the examples and test directories and Rubular is a great place to test your Regexp.

Note on Patches/Pull Requests

Fork the project.
Make your feature addition or bug fix.
Add tests for it. This is important so I don't break it in a future version unintentionally.
Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
Send me a pull request. Bonus points for topic branches.