--- /dev/null
+# OrderedHash is namespaced to prevent conflicts with other implementations
+module ActiveSupport
+ # Hash is ordered in Ruby 1.9!
+ if RUBY_VERSION >= '1.9'
+ OrderedHash = ::Hash
+ else
+ class OrderedHash < Array #:nodoc:
+ def []=(key, value)
+ if pair = assoc(key)
+ pair.pop
+ pair << value
+ else
+ self << [key, value]
+ end
+ value
+ end
+
+ def [](key)
+ pair = assoc(key)
+ pair ? pair.last : nil
+ end
+
+ def delete(key)
+ pair = assoc(key)
+ pair ? array_index = index(pair) : nil
+ array_index ? delete_at(array_index).last : nil
+ end
+
+ def keys
+ collect { |key, value| key }
+ end
+
+ def values
+ collect { |key, value| value }
+ end
+
+ def to_hash
+ returning({}) do |hash|
+ each { |array| hash[array[0]] = array[1] }
+ end
+ end
+
+ def has_key?(k)
+ !assoc(k).nil?
+ end
+
+ alias_method :key?, :has_key?
+ alias_method :include?, :has_key?
+ alias_method :member?, :has_key?
+
+ def has_value?(v)
+ any? { |key, value| value == v }
+ end
+
+ alias_method :value?, :has_value?
+ end
+ end
+end