OrderPreservingDictionary preserves the order in which elements were added to to it.
Metacello new
	baseline: 'OrderPreservingDictionary';
	repository: 'github://GsDevKit/OrderPreservingDictionary:gemstone/filetree';
	load.project install --url=http://gsdevkit.github.io/GsDevKit_home/OrderPreservingDictionary.ston
project load OrderPreservingDictionary
Basic Dictionary
(dict := Dictionary new)
	at: #apple put: 20;
	at: #orange put: 15.
dict keys. "#(#orange #apple)"OrderPreservingDictionary
(dict := OrderPreservingDictionary new)
	at: #apple put: 20;
	at: #orange put: 15.
dict keys. "#(#apple #orange)"