= key_struct

Defines KeyStruct, which is the same as ruby's Struct, but the initializer
takes keyword args (using a hash, rails-style).  Use it to define a class via:

  Name = KeyStruct[:first, :last]

or as an anonymous base class for your own enhanced struct:

  class Name < KeyStruct[:first, :last]
    def to_s
      "#{@last}, #{@first}"
    end
  end

Then you can create an instance of the class using keywords for the parameters:

  name = Name.new(:first => "Jack", :last => "Ripper")

and you have the usal readers and writers:

  name.first            --> "Jack"
  name.last             --> "Ripper"
  name.last = "Sprat"
  name.last             --> "Sprat"
  name.to_s             --> "Sprat, Jack" for the enhanced class example

If you leave off a keyword when instantiating, normally the value is nil:

  name = Name.new(:first => "Jack")
  name.last             --> nil

But the class definition can specify defaults, e.g.

  Name = KeyStruct[:first, :last => "Doe"]
  name = Name.new(:first => "John")
  name.first            --> "John"
  name.last             --> "Doe"

The struct initializer checks for invalid arguments:

  name = Name.new(:middle => "Xaviar")  --> raises ArgumentError

The gem actually provides two types of KeyStruct classes

  KeyStruct.accesor(*keys)      # aliased as KeyStruct[]
  KeyStruct.reader(*keys)       # class has readers but not writers

== Installation

Install via:

   % gem install key_struct

or in your Gemfile:

   gem "key_struct"

== Versions

Requires ruby >= 1.9.2.  (Has been tested on MRI 1.9.2 and MRI 1.9.3)

== History

Future: I hope that this gem will be obviated in future versions of ruby.

== 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.  Make sure that the coverage report
  (generated automatically when you run rspec) is at 100%
* 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.

== Copyright

Released under the MIT License.  See LICENSE for details.