playground.clj

(transform
  [MAP-VALS
   (view frequencies)
   (collect-one (view #(apply max (vals %))))]
  (fn [mx fs] (transform MAP-VALS #(/ % mx) fs))
  {:a [1 1 3 4] :b [1 1 2 2 2 3]})

;; => {:a {1 1, 3 1/2, 4 1/2}, :b {1 2/3, 2 1, 3 1/3}}

;; could in theory be written as:

(xform-> {:a [1 1 3 4] :b [1 1 2 2 2 3]}
  MAP-VALS
  (view frequencies)
  (collect-one (view #(apply max (vals %))))
  (fn [mx fs]
    (xform-> fs MAP-VALS #(/ % mx))))

;; could in theory be written as:

(defni normalize
  "Returns `m` with each of its values divided by `mx`."
  [mx (m map-vals)]
  (/ m mx))

(defni map-vals-normalize
  "Destructures the view of `frequencies` over the values of the passed map to
  `m` and the max value of `m`'s values as `mx`. Returns a map of normalized
  frequency maps for the values of the map passed in."
  [([m mx] map-vals
           (view frequencies)
           (collect-one (view #(apply max (vals %)))))]
  (normalize mx m))

;; where a list inside the argument vector represents applying a selector to the
;; passed in value and destructuring its results to the symbols in the first
;; element of the list