I've been using this instead of OpenStruct lately

gistfile1.rb

SomeObj = Struct.new(:foo, :bar, :baz) do
  def initialize(foo:, bar:, baz: 'is optional')
    self.foo = foo
    self.bar = bar
    self.baz = baz
  end
end

p SomeObj.new(foo: 1, bar: 2)
p SomeObj.new(foo: 1, bar: 2, baz: 'overridden')

some_hash = { foo: 'the foo', bar: 'the bar', baz: 'the baz'}
p SomeObj.new(some_hash)