Help needed with recursively merging maps

[enajski]

Hey, I've been trying all morning to figure this one out:

(def input 
  [{:id 1
     :datapoints {[:a1 :b1 :c1 :d1] [1 1 0 0]
                          [:a1 :b2 :c1 :d1] [1 1 1 1]
                          [:a1 :b2 :c1 :d2] [1 0 0 0]}}
    {:id 2
     :datapoints {[:a1 :b1 :c1 :d1] [1 1 0 0]
                          [:a1 :b2 :c1 :d1] [1 1 1 1]
                          [:a1 :b2 :c1 :d2] [1 0 0 0]}}])

;;expected shape
[{:id 1
  :figures {:b1 {:d1 1}
                 :b2 {:d1 1
                         :d2 1}}}
 {:id 2
  :figures {:b1 {:d1 1}
                 :b2 {:d1 1
                         :d2 1}}}]

Normally I'd do this:

(->> input
     (map (fn [in]
            {:id (:id in)
             :figures (reduce-kv (fn [m [_ b _ d] v]
                                   (assoc-in m [b d] (first v)))
                                 {}
                                 (:datapoints in))})))

but I wanted to try this out with meander. I got this working:

(m/search
  input
  (m/scan {:id ?id :datapoints {[_ ?b _ ?d] ?v}})
  {:id ?id
   :figures {?b {?d (first ?v)}}})

;; => ({:id 1, :figures {:b1 {:d1 1}}} {:id 1, :figures {:b2 {:d1 1}}} {:id 1, :figures {:b2 {:d2 1}}} {:id 2, :figures {:b1 {:d1 1}}} {:id 2, :figures {:b2 {:d1 1}}} {:id 2, :figures {:b2 {:d21}}})

But how do I get it to recursively merge the maps with the same ?id? I tried playing around with m/cata but to no avail. Thanks!

[noprompt]

Here's what I came up with.

(def input 
  [{:id 1
    :datapoints {[:a1 :b1 :c1 :d1] [1 1 0 0]
                 [:a1 :b2 :c1 :d1] [1 1 1 1]
                 [:a1 :b2 :c1 :d2] [1 0 0 0]}}
   {:id 2
    :datapoints {[:a1 :b1 :c1 :d1] [1 1 0 0]
                 [:a1 :b2 :c1 :d1] [1 1 1 1]
                 [:a1 :b2 :c1 :d2] [1 0 0 0]}}])

(m/rewrite input
  [{:id ?id & ?rest-map} & ?rest-vector]
  [{:id ?id :figures (m/cata ?rest-map)} & (m/cata ?rest-vector)]

  (m/with [%entry [[_ ?k1 _ !k2] [!v & _]]]
    {:datapoints (m/seqable %entry . (m/or %entry !other-entry) ...)})
  {?k1 {& [[!k2 !v] ...]} & (m/cata {:datapoints {& [!other-entry ...]}})}

  _
  {})
;; =>
[{:id 1, :figures {:b2 {:d1 1, :d2 1}, :b1 {:d1 1}}}
 {:id 2, :figures {:b2 {:d1 1, :d2 1}, :b1 {:d1 1}}}]

[noprompt]

Isolating only the map manipulation portion.

(let [data {:id 1
            :datapoints {[:a1 :b1 :c1 :d1] [1 1 0 0]
                         [:a1 :b2 :c1 :d1] [1 1 1 1]
                         [:a1 :b2 :c1 :d2] [1 0 0 0]}}]
  (m/rewrite data
    {:id (m/some ?id) & ?rest-map}
    {:id ?id :figures (m/cata ?rest-map)}

    (m/with [%entry [[_ ?k1 _ !k2] [!v & _]]]
      {:datapoints (m/seqable %entry . (m/or %entry !other-entry) ...)})
    {?k1 {& [[!k2 !v] ...]} & (m/cata {:datapoints {& [!other-entry ...]}})}

    _
    {}))
;; =>
{:id 1, :figures {:b2 {:d1 1, :d2 1}, :b1 {:d1 1}}}

[enajski]

Thanks for taking this one apart!