class ActiveSupport::OrderedOptions


h.dog! # => raises KeyError: key not found: :dog
bang to the key name, like:
To raise an exception when the value is blank, append a
h.dog # => nil
h.girl # => ‘Mary’
h.boy # => ‘John’
h.girl = ‘Mary’
h.boy = ‘John’
h = ActiveSupport::OrderedOptions.new
Using OrderedOptions, the above code could be reduced to:<br><br>h # => nil<br>h # => ‘Mary’<br>h # => ‘John’<br>h = ‘Mary’<br>h = ‘John’
h = {}
Usually key value pairs are handled something like this:

def [](key) 

def [](key)
  super(key.to_sym)
end

def []=(key, value) 

def []=(key, value)
  super(key.to_sym, value)
end

def method_missing(name, *args) 

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

def respond_to_missing?(name, include_private) 

def respond_to_missing?(name, include_private)
  true
end