[
  <b3da98d2-57cf-11e7-b564-6c4008925d80> -- fact ID
  DUP "name" "something" 'INDEX/STRING (value => key component transformer) ATTR/ASSOC
  DUP "tags" ["nature" "photo"] [] ATTR/ASSOCVAL ( associate value only, no index )
  DUP "hasTag" "nature" 'INDEX/STRING ATTR/ASSOC
  DUP "hasTag" "photo" 'INDEX/STRING ATTR/ASSOC
  (the above tagging example can be simplified by adding some "list" primitives)
  DUP "timestamp" HLC [] ATTR/ASSOCUNIQ (can't have more than 1 "timestamp" attribute indexed)
] WRITE