Supporting transformations in cursors

query-cusors.clj

(def app-state (atom {:options [{:id "1" :name "test1" :creative_type_id "2"}
                                {:id "2" :name "test2" :creative_type_id "1"}
                                {:id "3" :name "test3" :creative_type_id "1"}
                                {:id "4" :name "test4" :creative_type_id "2"}]
                      :creatives [{:id "1" :name "my creative" :type_id "1"}]}}))
                      


(let [ref (q
            (select
              ;;construct builds a proxy cursor
              (construct {:value (?- ['op :id])
                          :description (?- ['op :name])})
              (from 
                (join [:options] 'op)
                (join [:creatives] 'c (on (eq (?- ['c :type_id])
                                              (?- ['op :creative_type_id]))))))
            (om/root-cursor app-cursor)]
      (om/transact! ref [0 :description] "test-updated")])

;;below is the state of app after the trasact is applied
#_{:options [{:id "1" :name "test1" :creative_type_id "2"}
             {:id "2" :name "test-updated" :creative_type_id "1"}
             {:id "3" :name "test3" :creative_type_id "1"}
             {:id "4" :name "test4" :creative_type_id "2"}]
   :creatives [{:id "1" :name "my creative" :type_id "1"}]}