Improve show performance by only evaluating each :render-fn once

src/nextjournal/clerk/render.cljs

@@ -217,13 +217,16 @@
 (defn read-string [s]
   (js/nextjournal.clerk.sci_env.read-string s))
 
+(defn replace-viewer-fns [{:as doc :keys [name->viewer]}]
+  (assoc (w/postwalk-replace name->viewer doc)
+         :name->viewer name->viewer))
 
 (defn fetch! [{:keys [blob-id]} opts]
   #_(js/console.log :fetch! blob-id opts)
   (-> (js/fetch (str "/_blob/" blob-id (when (seq opts)
                                          (str "?" (opts->query opts)))))
       (.then #(.text %))
-      (.then #(try (read-string %)
+      (.then #(try (replace-viewer-fns (read-string %))
                    (catch js/Error e
                      (js/console.error #js {:message "sci read error" :blob-id blob-id :code-string % :error e})
                      (render-unreadable-edn %))))))
@@ -345,21 +348,20 @@
       [triangle expanded?]]
      [:span.group-hover:text-indigo-700 opening-paren]]))
 
-(defn render-coll [xs {:as opts :keys [path viewer !expanded-at] :or {path []}}]
+(defn render-coll [xs {:as opts :keys [closing-parens path viewer !expanded-at] :or {path []}}]
   (let [expanded? (get @!expanded-at path)
         {:keys [opening-paren closing-paren]} viewer]
     [:span.inspected-value.whitespace-nowrap
      {:class (when expanded? "inline-flex")}
      [:span
-      (if (< 1 (count xs))
+      (if (expandable? xs)
         [expand-button !expanded-at opening-paren path]
         [:span opening-paren])
       (into [:<>]
             (comp (inspect-children opts)
                   (interpose (if expanded? [:<> [:br] triangle-spacer nbsp (when (= 2 (count opening-paren)) nbsp)] " ")))
             xs)
-      [:span
-       (cond->> closing-paren (list? closing-paren) (into [:<>]))]]]))
+      (into [:span] (or closing-parens [closing-paren]))]]))
 
 (defn render-elision [{:as fetch-opts :keys [total offset unbounded?]} _]
   [view-context/consume :fetch-fn
@@ -372,21 +374,6 @@
        :on-click #(when (fn? fetch-fn)
                     (fetch-fn fetch-opts))} (- total offset) (when unbounded? "+") (if (fn? fetch-fn) " more…" " more elided")])])
 
-(defn render-map [xs {:as opts :keys [path viewer !expanded-at] :or {path []}}]
-  (let [expanded? (get @!expanded-at path)
-        {:keys [closing-paren]} viewer]
-    [:span.inspected-value.whitespace-nowrap
-     {:class (when expanded? "inline-flex")}
-     [:span
-      (if (expandable? xs)
-        [expand-button !expanded-at "{" path]
-        [:span "{"])
-      (into [:<>]
-            (comp (inspect-children opts)
-                  (interpose (if expanded? [:<> [:br] triangle-spacer nbsp #_(repeat (inc (count path)) nbsp)] " ")))
-            xs)
-      (cond->> closing-paren (list? closing-paren) (into [:<>]))]]))
-
 
 (defn render-string [s {:as opts :keys [path !expanded-at] :or {path []}}]
   (let [expanded? (get @!expanded-at path)]
@@ -398,16 +385,16 @@
                   (inspect-presented opts %)))
           (if (string? s) [s] s))))
 
-(defn render-quoted-string [s {:as opts :keys [path viewer !expanded-at] :or {path []}}]
+(defn render-quoted-string [s {:as opts :keys [closing-parens path viewer !expanded-at] :or {path []}}]
   (let [{:keys [opening-paren closing-paren]} viewer]
     [:span.inspected-value.inline-flex
      [:span.cmt-string
       (if (some #(and (string? %) (str/includes? % "\n")) (if (string? s) [s] s))
         [expand-button !expanded-at opening-paren path]
         [:span opening-paren])]
-     [:div
-      [:span.cmt-string (viewer/->value (render-string s opts)) (first closing-paren)]
-      (when (list? closing-paren) (into [:<>] (rest closing-paren)))]]))
+     (into [:div
+            [:span.cmt-string (viewer/->value (render-string s opts)) (first closing-paren)]
+            (rest closing-parens)])]))
 
 (defn render-number [num]
   [:span.cmt-number.inspected-value
@@ -528,6 +515,8 @@
    (if (valid-react-element? x)
      x
      (let [{:nextjournal/keys [value viewer] :keys [path]} x]
+       (when-not (:render-fn viewer)
+         (throw (ex-info "A render function is missing" {:viewer viewer})))
        #_(prn :inspect-presented value :valid-element? (react/isValidElement value) :viewer viewer)
        ;; each view function must be called in its own 'functional component' so that it gets its own hook state.
        ^{:key (str (:hash viewer) "@" (peek (:path opts)))}
@@ -631,7 +620,7 @@
     (when (exists? js/window)
       ;; TODO: can we restore the scroll position when navigating back?
       (.scrollTo js/window #js {:top 0}))
-    (reset! !doc doc))
+    (reset! !doc (replace-viewer-fns doc)))
   ;; (when (and error (contains? @!doc :status))
   ;;   (swap! !doc dissoc :status))
   (when (remount? doc)
@@ -644,10 +633,10 @@
 
 (defn patch-state! [{:keys [patch]}]
   (if (remount? patch)
-    (do (swap! !doc #(re-eval-viewer-fns (apply-patch % patch)))
+    (do (swap! !doc #(re-eval-viewer-fns (replace-viewer-fns (apply-patch % patch))))
         ;; TODO: figure out why it doesn't work without `js/setTimeout`
         (js/setTimeout #(swap! !eval-counter inc) 10))
-    (swap! !doc apply-patch patch)))
+    (swap! !doc #(replace-viewer-fns (apply-patch % patch)))))
 
 (defonce !pending-clerk-eval-replies
   (atom {}))

src/nextjournal/clerk/view.clj

@@ -1,15 +1,31 @@
 (ns nextjournal.clerk.view
-  (:require [nextjournal.clerk.viewer :as v]
-            [hiccup.page :as hiccup]
+  (:require [clojure.java.io :as io]
+            [clojure.set :as set]
             [clojure.string :as str]
-            [clojure.java.io :as io])
+            [clojure.walk :as walk]
+            [hiccup.page :as hiccup]
+            [nextjournal.clerk.viewer :as v])
   (:import (java.net URI)))
 
+
+(defn ^:private extract-name->viewer [presentation]
+  (into {}
+        (map (juxt (fn [viewer]
+                     (or (when (qualified-symbol? (:name viewer))
+                           (symbol (namespace (:name viewer)) (str (name (:name viewer)) "$" (:hash viewer))))
+                         (symbol "nextjournal.clerk.viewer" (str "viewer-fn$" (:hash viewer))))) identity))
+        (keep :nextjournal/viewer (tree-seq (some-fn map? vector?) #(cond-> % (map? %) vals) presentation))))
+
+(defn +name->viewer [presentation]
+  (let [name->viewer (extract-name->viewer presentation)]
+    (assoc (walk/postwalk-replace (set/map-invert name->viewer) presentation)
+           :name->viewer name->viewer)))
+
 (defn doc->viewer
   ([doc] (doc->viewer {} doc))
   ([opts {:as doc :keys [ns file]}]
    (binding [*ns* ns]
-     (-> (merge doc opts) v/notebook v/present))))
+     (-> (merge doc opts) v/notebook v/present +name->viewer))))
 
 #_(doc->viewer (nextjournal.clerk/eval-file "notebooks/hello.clj"))
 #_(nextjournal.clerk/show! "notebooks/test.clj")

src/nextjournal/clerk/viewer.cljc

@@ -838,7 +838,7 @@
   {:name `sequential-viewer :pred sequential? :render-fn 'nextjournal.clerk.render/render-coll :opening-paren "(" :closing-paren ")" :page-size 20})
 
 (def map-viewer
-  {:name `map-viewer :pred map? :render-fn 'nextjournal.clerk.render/render-map :opening-paren "{" :closing-paren "}" :page-size 10})
+  {:name `map-viewer :pred map? :render-fn 'nextjournal.clerk.render/render-coll :opening-paren "{" :closing-paren "}" :page-size 10})
 
 #?(:cljs (defn var->symbol [v] (if (instance? sci.lang.Var v) (sci.impl.vars/toSymbol v) (symbol v))))
 
@@ -1548,7 +1548,7 @@
 
 (defn ^:private present-elision* [!path->wrapped-value {:as fetch-opts :keys [path]}]
   (if-let [wrapped-value (@!path->wrapped-value path)]
-    (present* (merge wrapped-value (make-!budget-opts wrapped-value) fetch-opts))
+    (assign-closing-parens (present* (merge wrapped-value (make-!budget-opts wrapped-value) fetch-opts)))
     (throw (ex-info "could not find wrapped-value at path" {:!path->wrapped-value !path->wrapped-value :fetch-otps fetch-opts}))))
 
 
@@ -1722,10 +1722,9 @@
                              (or (-> value last :nextjournal/viewer :closing-paren) ;; the last element can carry parens
                                  (and (= `map-entry-viewer (-> value last :nextjournal/viewer :name)) ;; the last element is a map entry whose value can carry parens
                                       (-> value last :nextjournal/value last :nextjournal/viewer :closing-paren))))]
-     (cond-> (cond
-               (not closing) node
-               defer-closing? (update node :nextjournal/viewer dissoc :closing-paren)
-               :else (update-in node [:nextjournal/viewer :closing-paren] cons closing-parens))
+     (cond-> (assoc-in node [:nextjournal/render-opts :closing-parens] (if (or (not closing) defer-closing?)
+                                                                         '()
+                                                                         (cons closing closing-parens)))
        non-leaf? (update :nextjournal/value
                          (fn [xs]
                            (into []

src/nextjournal/clerk/webserver.clj

@@ -84,7 +84,7 @@
       (if (contains? desc :nextjournal/content-type)
         {:body (v/->value desc)
          :content-type (:nextjournal/content-type desc)}
-        {:body (v/->edn desc)}))
+        {:body (v/->edn (view/+name->viewer desc))}))
     {:status 404}))
 
 (defn extract-blob-opts [{:as _req :keys [uri query-string]}]
@@ -173,8 +173,6 @@
     (apply swap! nextjournal.clerk.atom/my-state (eval '[update :counter inc]))
     (eval '(nextjournal.clerk/recompute!)))
 
-(declare present+reset!)
-
 (defn ->nav-path [file-or-ns]
   (cond (or (symbol? file-or-ns) (instance? clojure.lang.Namespace file-or-ns))
         (str "'" file-or-ns)

test/nextjournal/clerk/eval_test.clj

@@ -173,14 +173,14 @@
                      (mapv #(select-keys % [:nextjournal/width]))))))
 
   (testing "can handle uncounted sequences"
-    (is (match? [{:nextjournal/viewer {:name `viewer/code-block-viewer}
+    (is (match? [{:nextjournal/viewer `viewer/code-block-viewer$5dru1FUcVRTRrVKJFbNw4FG2wXmiwB
                   :nextjournal/value "(range)"}
                  {:nextjournal/value {:nextjournal/fetch-opts {:blob-id string?}
                                       :nextjournal/hash string?}}]
                 (eval+extract-doc-blocks "(range)"))))
 
   (testing "assigns folded visibility"
-    (is (match? [{:nextjournal/viewer {:name `viewer/folded-code-block-viewer}
+    (is (match? [{:nextjournal/viewer `viewer/folded-code-block-viewer$5dt3F3pXDCJHWEKwRWd1FTwBTC7bQ1
                   :nextjournal/value "{:some :map}"}
                  {:nextjournal/value {:nextjournal/fetch-opts {:blob-id string?}
                                       :nextjournal/hash string?}}]

test/nextjournal/clerk/viewer_test.clj

@@ -179,18 +179,21 @@
     (is (match? {:nextjournal/value "10/33"}
                 (v/present 10/33))))
 
-  (testing "opts are not propagated to children during presentation"
-    (let [count-opts (fn [o]
+  (testing "render opts are not propagated to children during presentation"
+    (let [count-opts (fn [o k]
                        (let [c (atom 0)]
-                         (w/postwalk (fn [f] (when (= :nextjournal/render-opts f) (swap! c inc)) f) o)
+                         (w/postwalk (fn [f] (when (and (map? f)
+                                                        (contains? f :nextjournal/render-opts)
+                                                        (-> f :nextjournal/render-opts k))
+                                               (swap! c inc)) f) o)
                          @c))]
       (let [presented (v/present (v/col {:nextjournal.clerk/render-opts {:width 150}} 1 2 3))]
-        (is (= {:width 150} (:nextjournal/render-opts presented)))
-        (is (= 1 (count-opts presented))))
+        (is (match? {:width 150} (:nextjournal/render-opts presented)))
+        (is (= 1 (count-opts presented :width))))
 
       (let [presented (v/present (v/table {:col1 [1 2] :col2 '[a b]}))]
-        (is (= {:num-cols 2 :number-col? #{0}} (:nextjournal/render-opts presented)))
-        (is (= 1 (count-opts presented))))))
+        (is (match? {:num-cols 2 :number-col? #{0}} (:nextjournal/render-opts presented)))
+        (is (= 1 (count-opts presented :num-cols))))))
 
   (testing "viewer opts are normalized"
     (is (= (v/desc->values (v/present {:nextjournal/value (range 10) :nextjournal/budget 3}))
@@ -225,14 +228,14 @@
              (-> after
                  (get-in (path-to-value [0 1 1]))
                  (get 2)
-                 v/->viewer
-                 :closing-paren)))
+                 :nextjournal/render-opts
+                 :closing-parens)))
       (is (= '(")" "}")
              (-> after
                  (get-in (path-to-value [1]))
                  (get 1)
-                 v/->viewer
-                 :closing-paren))))))
+                 :nextjournal/render-opts
+                 :closing-parens))))))
 
 (defn tree-re-find [data re]
   (->> data
@@ -351,23 +354,27 @@
     (is (= 5
            (count
             (->> (eval/eval-string "^{:nextjournal.clerk/budget 5}(reduce (fn [acc _i] (vector acc)) :fin (range 100 0 -1))")
-                 view/doc->viewer v/->value :blocks
+                 view/doc->viewer  v/->value
+                 :blocks
                  (tree-seq coll? seq)
-                 (filter (every-pred map? (comp #{'nextjournal.clerk.render/render-coll} :form :render-fn)))))))
+                 (keep :nextjournal/viewer)
+                 (filter #{'nextjournal.clerk.viewer/vector-viewer$5dsD1KJESfc8Dy8gPeGQfZCX2ayE8f})))))
 
     (is (= 5
            (count
             (->> (eval/eval-string "(nextjournal.clerk/with-viewer {} {:nextjournal.clerk/budget 5} (reduce (fn [acc i] (vector acc)) :fin (range 15 0 -1)))")
                  view/doc->viewer v/->value :blocks
                  (tree-seq coll? seq)
-                 (filter (every-pred map? (comp #{'nextjournal.clerk.render/render-coll} :form :render-fn)))))))
+                 (keep :nextjournal/viewer)
+                 (filter #{'nextjournal.clerk.viewer/vector-viewer$5dsD1KJESfc8Dy8gPeGQfZCX2ayE8f})))))
 
     (is (= 101
            (count
             (->> (eval/eval-string "^{:nextjournal.clerk/budget nil}(reduce (fn [acc i] (vector i acc)) :fin (range 101 0 -1))")
                  view/doc->viewer v/->value :blocks
                  (tree-seq coll? seq)
-                 (filter (every-pred map? (comp #{'nextjournal.clerk.render/render-coll} :form :render-fn)))))))))
+                 (keep :nextjournal/viewer)
+                 (filter #{'nextjournal.clerk.viewer/vector-viewer$5dsD1KJESfc8Dy8gPeGQfZCX2ayE8f})))))))
 
 (deftest ->edn
   (testing "normal symbols and keywords"

test/nextjournal/clerk/webserver_test.clj

@@ -16,7 +16,6 @@
           {:nextjournal/keys [value]} presented
           {elision-viewer :nextjournal/viewer elision-fetch-opts :nextjournal/value} (peek value)
           {:keys [body]} (webserver/serve-blob doc (merge fetch-opts {:fetch-opts elision-fetch-opts}))]
-      (is (= `nextjournal.clerk.viewer/elision-viewer (:name elision-viewer)))
+      (is (= `nextjournal.clerk.viewer/elision-viewer$5drduatKq2QJCDhSX1Pu45i4whSPHk elision-viewer))
       (is body)
       (is (= (-> body webserver/read-msg :nextjournal/value first :nextjournal/value) 20)))))
-