module ActiveSupport # 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 # class OrderedOptions < Hash alias_method :_get, :[] # preserve the original #[] method protected :_get # make it protected def []=(key, value) super(key.to_sym, value) end def [](key) super(key.to_sym) end 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) true end end # +InheritableOptions+ provides a constructor to build an +OrderedOptions+ # hash inherited from another hash. # # Use this if you already have some hash and you want to create a new one based on it. # # h = ActiveSupport::InheritableOptions.new({ girl: 'Mary', boy: 'John' }) # h.girl # => 'Mary' # h.boy # => 'John' class InheritableOptions < OrderedOptions def initialize(parent = nil) if parent.kind_of?(OrderedOptions) # use the faster _get when dealing with OrderedOptions super() { |h,k| parent._get(k) } elsif parent super() { |h,k| parent[k] } else super() end end def inheritable_copy self.class.new(self) end end end