A with keyword for Ruby

(That has nothing to do with python's with keyword)

with lets you seamlessly make any object the current context.

Why

I'm tired of doing this:

users.each do |user|
  puts user.name
end

Or things like this:

Project.new.tap do |proj|
  proj.name = "hello"
  proj.owner = owner
  proj.created_at = Time.now
end

So I made it way more -- well, Ruby-ish.

with Project.new do
  puts "A project called #{name}
        was started by #{owner}
        at #{created_at}."
end

The with keyword

Note: Ruby 1.9x only for now!

To access object variables without typing self, just call with on that object:

users.each do |user|
  with user do
    puts name
  end
end

To SET the object's variables, use the usual self.attribute = val method, or one of two provided methods that can make that far less annoying:

with user do
  set name: 'Leo'
  puts name # => Leo

  # OR
  self <= { name: 'CJ' }

  # Of course you can still do it the original way
  # (which is exactly what the above two methods do behind-the-scenes)
  self.name = "Jed"
end

Use it!

You have two options to use ruby-with in your app:

1. Keyword-level integration (make with available everywhere, because why not?):

   # In your Gemfile
   gem 'ruby-with', require: 'ruby-with/global'

1. On a class-by-class basis:

   # In your Gemfile
   gem 'ruby-with'

   # MyClass
   class MyClass
     include RubyWith::With
   end

Advanced

You can call with with an optional second argument (a Hash) that will be set before all your code is run.

with Dog.new, name: 'Rue' do
  puts name # => Rue
end

Or, if you need access to your current context (kind of like inverting your existing code), you can do this:

class Dog < Pet

  belongs_to :owner

  attr_accessor :name

  def initialize(name)
    self.name = name

    with owner do |dog|
      dog.name = "#{dog.name} #{last_name}" # => looks like 'DogName OwnerLastName'
    end
  end
end

It's kind of a contrived example, but I'm sure it'll come in handy.

Changelog

• Release 0.2: Added setters and new documentation.