• atomicobject.github.com/constructor

Declarative means to define object properties by passing a hash to the constructor, which will set the corresponding ivars.

require 'constructor'

class Horse
  constructor :name, :breed, :weight
end
Horse.new :name => 'Ed', :breed => 'Mustang', :weight => 342

By default the ivars do not get accessors defined. But you can get them auto-made if you want:

class Horse
  constructor :name, :breed, :weight, :accessors => true
end
...
puts my_horse.weight

Arguments specified are required by default. You can disable strict argument checking with :strict option. This means that the constructor will not raise an error if you pass more or fewer arguments than declared.

class Donkey
  constructor :age, :odor, :strict => false
end

… this allows you to pass either an age or odor key (or neither) to the Donkey constructor.

• rubygems

• gem install constructor

• David Crosby (crosby@atomicobject.com)

• Patrick Bacon (bacon@atomicobject.com)

• © 2007-2011 Atomic Object

• More Atomic Object open source projects

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