require 'yaml' YAML.add_builtin_type("omap") do |type, val| ActiveSupport::OrderedHash[val.map{ |v| v.to_a.first }] end module ActiveSupport # DEPRECATED: ActiveSupport::OrderedHash implements a hash that preserves # insertion order. # # oh = ActiveSupport::OrderedHash.new # oh[:a] = 1 # oh[:b] = 2 # oh.keys # => [:a, :b], this order is guaranteed # # Also, maps the +omap+ feature for YAML files # (See http://yaml.org/type/omap.html) to support ordered items # when loading from yaml. # # ActiveSupport::OrderedHash is namespaced to prevent conflicts # with other implementations. class OrderedHash < ::Hash def to_yaml_type "!tag:yaml.org,2002:omap" end def encode_with(coder) coder.represent_seq '!omap', map { |k,v| { k => v } } end def select(*args, &block) dup.tap { |hash| hash.select!(*args, &block) } end def reject(*args, &block) dup.tap { |hash| hash.reject!(*args, &block) } end def nested_under_indifferent_access self end # Returns true to make sure that this hash is extractable via Array#extract_options! def extractable_options? true end end end