Usually key value pairs are handled something like this:

h = {}
h[:boy] = 'John'
h[:girl] = 'Mary'
h[:boy]  # => 'John'
h[:girl] # => 'Mary'
h[:dog]  # => nil

Using OrderedOptions, the above code could be reduced to:

h = ActiveSupport::OrderedOptions.new
h.boy = 'John'
h.girl = 'Mary'
h.boy  # => 'John'
h.girl # => 'Mary'
h.dog  # => nil

To raise an exception when the value is blank, append a bang to the key name, like:

h.dog! # => raises KeyError: key not found: :dog
Methods
#
M
R
Instance Public methods
[](key)
Also aliased as: _get

Source: show | on GitHub 

# File activesupport/lib/active_support/ordered_options.rb, line 35
def [](key)
  super(key.to_sym)
end
[]=(key, value)

Source: show | on GitHub 

# File activesupport/lib/active_support/ordered_options.rb, line 31
def []=(key, value)
  super(key.to_sym, value)
end
_get(key)
Alias for: []
method_missing(name, *args)

Source: show | on GitHub 

# File activesupport/lib/active_support/ordered_options.rb, line 39
def method_missing(name, *args)
  name_string = name.to_s
  if name_string.chomp!("=")
    self[name_string] = args.first
  else
    bangs = name_string.chomp!("!")

    if bangs
      fetch(name_string.to_sym).presence || raise(KeyError.new("#{name_string} is blank."))
    else
      self[name_string]
    end
  end
end
respond_to_missing?(name, include_private)

Source: show | on GitHub 

# File activesupport/lib/active_support/ordered_options.rb, line 54
def respond_to_missing?(name, include_private)
  true
end