For educational purposes, obviously.

extract-dvsa-json-data.ix

(-> 'ls topics/*.json'
     exec
     (split '\n')
     (map read)
     (filter val)
     (map from-json)
     (map #(% 'questions'))
     flatten
     (flat-map extract-questions)
     to-json
     (write "test.json"))

(function extract-choices preamble assets config
  (let messages  (config 'messages')
       messages  (if messages
                     (-> messages (map (fn [k v] [(to-key k) (v 'text')])) dict)
                     {})
       choices   (-> 'choices' config (map #[(% 'label') (% 'correct')]) dict)
       text      (config 'text')
       image     (config 'image')
       image-url (assets image)
       extracted {:question text :choices choices}
       extracted (if preamble (extracted :preamble preamble) extracted)
       extracted (if image-url (extracted :image-url image-url) extracted))
  extracted)

(function extract-questions section
  (let config    (section 'config')
       assets    (-> 'assets' section (map (fn [k v] [k (v 'url')])) dict)
       text      (config 'text')
       questions (config 'questions'))
  (return-when questions (flat-map @(extract-choices text assets) questions))
  (extract-choices null assets config))