clojupyter.clj

(ns oz.notebook.clojupyter
  "Experimental support for rendering vega in Jupyter with Clojupyter"
  (:require
    ;[oz.core :as oz]
    ;[lazy-require.core :as lreq]
    [hiccup.core :as hiccup]
    [clojupyter.protocol.mime-convertible :as mc]
    [clojure.data.json :as json]))



(def require-string
  "
<div>
  <div id='uuid-%s'></div>
  <script>
  requirejs.config({
    baseUrl: 'https://cdn.jsdelivr.net/npm/',
    paths: {
      'vega-embed':  'vega-embed@3?noext',
      'vega-lib': 'vega-lib?noext',
      'vega-lite': 'vega-lite@2?noext',
      'vega': 'vega@3?noext'
    }
  });
  require(['vega-embed'], function(vegaEmbed) {
    let spec = %s;
    vegaEmbed('#uuid-%s', spec, {defaultStyle:true}).catch(console.warn);
    }, function(err) {
    console.log('Failed to load');
  });
  </script>
</div>
  ")


(defn- uuid [] (str (java.util.UUID/randomUUID)))

(defn- live-embed [v]
  (let [id (uuid)]
    (format require-string id (json/write-str v) id)))


;; Would ideally like to use lazy require so that clojupyter isn't a hard requirement, but unfortunately, it doesn't work with reify presently
;(defn view! [spec]
  ;;; problematic to always run?
  ;(lreq/with-lazy-require
    ;[[clojupyter.protocol.mime-convertible :as mc]]
    ;(reify
      ;mc/PMimeConvertible
      ;(to-mime [this]
        ;(mc/stream-to-string
          ;{:text/html (hiccup/html (oz/embed spec {:embed-fn live-embed}))})))))


;; NOTE This function has been duplicated from oz.core in order to avoid a bug with loading in Clojupyter.
;; TODO Once that underlying bug has been resolved, we should remove this duplication, and refer to oz.core again.
(defn ^:no-doc embed
  "Take hiccup or vega/lite spec and embed the vega/lite portions using vegaEmbed, as hiccup :div and :script blocks.
  When rendered, should present as live html page; Currently semi-private, may be made fully public in future."
  ([spec {:as opts :keys [embed-fn] :or {embed-fn live-embed}}]
   ;; prewalk spec, rendering special hiccup tags like :vega and :vega-lite, and potentially other composites,
   ;; rendering using the components above. Leave regular hiccup unchanged).
   ;; TODO finish writing; already hooked in below so will break now
   (clojure.walk/prewalk
     (fn [x] (if (and (coll? x) (#{:vega :vega-lite} (first x)))
               (embed-fn x)
               x))
     spec))
  ([spec]
   (embed spec {})))

(defn ^:no-doc embed
  "Take hiccup or vega/lite spec and embed the vega/lite portions using vegaEmbed, as hiccup :div and :script blocks.
  When rendered, should present as live html page; Currently semi-private, may be made fully public in future."
  ([spec {:as opts :keys [embed-fn] :or {embed-fn live-embed}}]
   ;; prewalk spec, rendering special hiccup tags like :vega and :vega-lite, and potentially other composites,
   ;; rendering using the components above. Leave regular hiccup unchanged).
   ;; TODO finish writing; already hooked in below so will break now
   (if (map? spec)
     (embed-fn spec)
     (clojure.walk/prewalk
       (fn [x] (if (and (coll? x) (#{:vega :vega-lite} (first x)))
                 (embed-fn (second x))
                 x))
       spec)))
  ([spec]
   (embed spec {})))

(defn view!
  "Display a vega or vega-lite spec from a Jupyter notebook using the Clojupyter kernel."
  [spec]
  (reify
    mc/PMimeConvertible
    (to-mime [this]
      (mc/stream-to-string
        ;; TODO switch back to oz.core/embed once this issue is resolved
        ;{:text/html (hiccup/html (oz/embed spec {:embed-fn live-embed}))}
        {:text/html (hiccup/html (embed spec {:embed-fn live-embed}))}))))