From ddbbfc436447e19ecbe75dd11e59224868cc9b64 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Wed, 12 Jan 2022 17:56:52 +0100
Subject: [PATCH 01/10] wip

---
 notebooks/rule_30.clj                 |   8 +-
 notebooks/viewer_api.clj              |  18 ++--
 src/nextjournal/clerk.clj             |  24 +-----
 src/nextjournal/clerk/sci_viewer.cljs |  36 ++++----
 src/nextjournal/clerk/viewer.cljc     | 114 +++++++++++---------------
 5 files changed, 87 insertions(+), 113 deletions(-)

diff --git a/notebooks/rule_30.clj b/notebooks/rule_30.clj
index c906a5e4c..bc59cd17a 100644
--- a/notebooks/rule_30.clj
+++ b/notebooks/rule_30.clj
@@ -4,10 +4,10 @@
   (:require [nextjournal.clerk :as clerk]))
 
 (clerk/set-viewers!
- [{:pred number? :render-fn #(v/html [:div.inline-block {:style {:width 16 :height 16}
-                                                         :class (if (pos? %) "bg-black" "bg-white border-solid border-2 border-black")}])}
-  {:pred list? :render-fn #(v/html (into [:div.flex.flex-col] (v/inspect-children %2) %1))}
-  {:pred #(and (vector? %) (not (map-entry? %))) :render-fn #(v/html (into [:div.flex.inline-flex] (v/inspect-children %2) %1))}])
+ [{:pred number? :render-fn '#(v/html [:div.inline-block {:style {:width 16 :height 16}
+                                                          :class (if (pos? %) "bg-black" "bg-white border-solid border-2 border-black")}])}
+  {:pred list? :render-fn '#(v/html (into [:div.flex.flex-col] (v/inspect-children %2) %1))}
+  {:pred #(and (vector? %) (not (map-entry? %))) :render-fn '#(v/html (into [:div.flex.inline-flex] (v/inspect-children %2) %1))}])
 
 0
 
diff --git a/notebooks/viewer_api.clj b/notebooks/viewer_api.clj
index 5b299fd57..a27ceb910 100644
--- a/notebooks/viewer_api.clj
+++ b/notebooks/viewer_api.clj
@@ -49,15 +49,15 @@
                             expression-2)))
 
 ;; ## 🚀 Extensibility
-(clerk/with-viewer #(v/html [:div "Greetings to " [:strong %] "!"])
+(clerk/with-viewer '#(v/html [:div "Greetings to " [:strong %] "!"])
   "James Maxwell Clerk")
 
-(clerk/with-viewers [{:pred number? :render-fn #(v/html [:div.inline-block [(keyword (str "h" %)) (str "Heading " %)]])}]
+(clerk/with-viewers [{:pred number? :render-fn '#(v/html [:div.inline-block [(keyword (str "h" %)) (str "Heading " %)]])}]
   [1 2 3 4 5])
 
 ^::clerk/no-cache
-(clerk/with-viewers [{:pred number? :render-fn #(v/html [:div.inline-block {:style {:width 16 :height 16}
-                                                                            :class (if (pos? %) "bg-black" "bg-white border-solid border-2 border-black")}])}]
+(clerk/with-viewers [{:pred number? :render-fn '#(v/html [:div.inline-block {:style {:width 16 :height 16}
+                                                                             :class (if (pos? %) "bg-black" "bg-white border-solid border-2 border-black")}])}]
   (take 10 (repeatedly #(rand-int 2))))
 
 (clerk/with-viewers
@@ -67,11 +67,11 @@
                   (str "(?i)"
                        "(#(?:[0-9a-f]{2}){2,4}|(#[0-9a-f]{3})|"
                        "(rgb|hsl)a?\\((-?\\d+%?[,\\s]+){2,3}\\s*[\\d\\.]+%?\\))")) %))
-    :render-fn #(v/html [:div.inline-block.rounded-sm.shadow
-                         {:style {:width 16
-                                  :height 16
-                                  :border "1px solid rgba(0,0,0,.2)"
-                                  :background-color %}}])}]
+    :render-fn '#(v/html [:div.inline-block.rounded-sm.shadow
+                          {:style {:width 16
+                                   :height 16
+                                   :border "1px solid rgba(0,0,0,.2)"
+                                   :background-color %}}])}]
   ["#571845"
    "rgb(144,12,62)"
    "rgba(199,0,57,1.0)"
diff --git a/src/nextjournal/clerk.clj b/src/nextjournal/clerk.clj
index 9cf3657c0..ff9a1ae40 100644
--- a/src/nextjournal/clerk.clj
+++ b/src/nextjournal/clerk.clj
@@ -240,27 +240,9 @@
 (def use-headers    #'v/use-headers)
 (def hide-result    #'v/hide-result)
 (defn doc-url [path] (v/->SCIEval (list 'v/doc-url path)))
-
-(defmacro with-viewer
-  [viewer x]
-  (let [viewer# (v/->Form viewer)]
-    `(v/with-viewer* ~viewer# ~x)))
-
-#_(macroexpand '(with-viewer #(v/html [:div %]) 1))
-
-(defmacro with-viewers
-  [viewers x]
-  (let [viewers# (v/process-fns viewers)]
-    `(v/with-viewers* ~viewers# ~x)))
-
-#_(macroexpand '(with-viewers [{:pred number? :render-fn #(v/html [:div %])}] 1))
-
-
-(defmacro set-viewers!
-  ([viewers] (v/set-viewers!* *ns* viewers))
-  ([scope viewers] (v/set-viewers!* scope viewers)))
-
-#_(set-viewers! [])
+(def with-viewer    #'v/with-viewer)
+(def with-viewers   #'v/with-viewers)
+(def set-viewers!   #'v/set-viewers!)
 
 (defn file->viewer
   "Evaluates the given `file` and returns it's viewer representation."
diff --git a/src/nextjournal/clerk/sci_viewer.cljs b/src/nextjournal/clerk/sci_viewer.cljs
index 1d8ec310f..f3d574e67 100644
--- a/src/nextjournal/clerk/sci_viewer.cljs
+++ b/src/nextjournal/clerk/sci_viewer.cljs
@@ -5,7 +5,7 @@
             [edamame.core :as edamame]
             [goog.object]
             [goog.string :as gstring]
-            [nextjournal.clerk.viewer :as viewer :refer [code html md plotly tex vl with-viewer* with-viewers*] :rename {with-viewer* with-viewer with-viewers* with-viewers}]
+            [nextjournal.clerk.viewer :as viewer :refer [code html md plotly tex vl with-viewer with-viewers]]
             [nextjournal.devcards :as dc]
             [nextjournal.markdown.transform :as md.transform]
             [nextjournal.viewer.code :as code]
@@ -391,7 +391,8 @@
   [:span.inspected-value.whitespace-nowrap
    [:span.syntax-tag tag] value])
 
-(defn normalize-viewer [x]
+(defn normalize-viewer
+  [x]
   (if-let [viewer (-> x meta :nextjournal/viewer)]
     (with-viewer viewer x)
     x))
@@ -413,19 +414,25 @@
 
 (declare default-viewers)
 
+(defn maybe-eval [render-fn]
+  (js/console.log :maybe-eval render-fn :eval? (or (symbol? render-fn) (list? render-fn)))
+  (cond-> render-fn
+    (or (symbol? render-fn) (list? render-fn))
+    *eval*))
+
 (defn render-with-viewer [{:as opts :keys [viewers]} viewer value]
-  #_(js/console.log :render-with-viewer {:value value :viewer viewer #_#_ :opts opts})
+  (js/console.log :render-with-viewer {:value value :viewer viewer #_#_ :opts opts})
   (cond (or (fn? viewer) (viewer/fn+form? viewer))
         (viewer value opts)
 
         (and (map? viewer) (:render-fn viewer))
-        (render-with-viewer opts (:render-fn viewer) value)
+        (render-with-viewer opts (maybe-eval (:render-fn viewer)) value)
 
         (keyword? viewer)
         (if-let [{:keys [fetch-opts render-fn]} (viewer/find-named-viewer viewers viewer)]
           (if-not render-fn
             (html (error-badge "no render function for viewer named " (str viewer)))
-            (render-fn value (assoc opts :fetch-opts fetch-opts)))
+            ((maybe-eval render-fn) value (assoc opts :fetch-opts fetch-opts)))
           (html (error-badge "cannot find viewer named " (str viewer))))
 
         :else
@@ -434,12 +441,15 @@
 (defn inspect
   ([x]
    (r/with-let [!expanded-at (r/atom {})]
-     [inspect {:!expanded-at !expanded-at} x]))
-  ([{:as opts :keys [viewers]} x]
+     [inspect {:!expanded-at !expanded-at :recursion 0} x]))
+  ([{:as opts :keys [viewers recursion]} x]
    (let [value (viewer/value x)
          {:as opts :keys [viewers]} (assoc opts :viewers (vec (concat (viewer/viewers x) viewers)))
-         all-viewers (viewer/get-viewers (:scope @!doc) viewers)]
-     (or (when (react/isValidElement value) value)
+         all-viewers (viewer/get-viewers (:scope @!doc) viewers)
+         opts (update opts :recursion inc)]
+     (js/console.log :inspect value)
+     (or (when (< 20 recursion) [:span "reached recursion limit"])
+         (when (react/isValidElement value) value)
          ;; TODO find option to disable client-side viewer selection
          (when-let [viewer (or (viewer/viewer x)
                                (viewer/viewer (viewer/wrapped-with-viewer value all-viewers)))]
@@ -491,7 +501,7 @@
                 id (get id))))
 
 (defn error-viewer [e]
-  (viewer/with-viewer* :code (pr-str e)))
+  (viewer/with-viewer :code (pr-str e)))
 
 
 (dc/defcard inspect-values
@@ -623,6 +633,7 @@
       [inspect @!error]])])
 
 (defn ^:export set-state [{:as state :keys [doc error]}]
+  (js/console.log :set-state state)
   (doseq [cell (viewer/value doc)
           :when (viewer/registration? cell)
           :let [form (viewer/value cell)]]
@@ -874,6 +885,7 @@ black")}]))}
   (html (katex/to-html-string tex-string)))
 
 (defn html-viewer [markup]
+  (js/console.log :html-viewer markup)
   (if (string? markup)
     (html [:div {:dangerouslySetInnerHTML {:__html markup}}])
     (r/as-element markup)))
@@ -969,7 +981,3 @@ black")}]))}
   (sci/eval-form @!sci-ctx f))
 
 (set! *eval* eval-form)
-
-(swap! viewer/!viewers (fn [viewers]
-                         (-> (into {} (map (juxt key (comp viewer/process-fns val))) viewers)
-                             (update :root concat js-viewers))))
diff --git a/src/nextjournal/clerk/viewer.cljc b/src/nextjournal/clerk/viewer.cljc
index e04ace507..ee5f60983 100644
--- a/src/nextjournal/clerk/viewer.cljc
+++ b/src/nextjournal/clerk/viewer.cljc
@@ -153,7 +153,7 @@
 
 (def elide-string-length 100)
 
-(declare with-viewer*)
+(declare with-viewer)
 
 (defn fetch-all [_ x] x)
 
@@ -219,42 +219,16 @@
    {:pred string? :render-fn (quote v/string-viewer) :fetch-opts {:n 100}}
    {:pred number? :render-fn '(fn [x] (v/html [:span.tabular-nums (if (js/Number.isNaN x) "NaN" (str x))]))}])
 
-(defn process-fns [viewers]
-  (into []
-        (map (fn [{:as viewer :keys [pred fetch-fn render-fn transform-fn]}]
-               ;; TODO: simplify with own type for things that should not be transmitted to the
-               ;; browser (`pred`, `fetch-fn` & `transform-fn`)
-               ;; also remove `symbol?` checks and let viewers use `(quote my-sym)` instead of `'my-sym`
-               (cond-> viewer
-                 (and pred (or (symbol? pred) (not (ifn? pred))))
-                 (update :pred #?(:cljs *eval* :clj #(->Fn+Form '(constantly false) (eval %))))
-
-                 (and transform-fn (or (symbol? transform-fn) (not (ifn? transform-fn))))
-                 (update :transform-fn #?(:cljs *eval* :clj #(->Fn+Form '(constantly false) (eval %))))
-
-                 (and fetch-fn (not (ifn? fetch-fn)))
-                 (update :fetch-fn #?(:cljs *eval* :clj #(->Fn+Form '(constantly false) (eval %))))
-
-                 #?@(:clj [(and render-fn (not (instance? Form render-fn)))
-                           (update :render-fn ->Form)]
-                     :cljs [(and render-fn (not (instance? Fn+Form render-fn)))
-                            (update :render-fn form->fn+form)]))))
-        viewers))
-
-(defn process-viewers [viewers]
-  #?(:clj (process-fns viewers)
-     :cljs viewers))
-
-(defn processed-default-viewers []
-  {:root (process-viewers default-viewers)
-   :table (process-viewers default-table-cell-viewers)})
+(def all-viewers
+  {:root default-viewers
+   :table default-table-cell-viewers})
 
 (defonce
   ^{:doc "atom containing a map of `:root` and per-namespace viewers."}
   !viewers
-  (#?(:clj atom :cljs ratom/atom) (processed-default-viewers)))
+  (#?(:clj atom :cljs ratom/atom) all-viewers))
 
-#_(reset! !viewers (processed-default-viewers))
+#_(reset! !viewers all-viewers)
 
 ;; heavily inspired by code from Thomas Heller in shadow-cljs, see
 ;; https://github.com/thheller/shadow-cljs/blob/1708acb21bcdae244b50293d17633ce35a78a467/src/main/shadow/remote/runtime/obj_support.cljc#L118-L144
@@ -278,7 +252,7 @@
     (set? xs) (sort resilient-compare xs)
     :else xs))
 
-(declare with-viewer*)
+(declare with-viewer)
 
 (defn find-named-viewer [viewers viewer-name]
   (first (filter (comp #{viewer-name} :name) viewers)))
@@ -311,8 +285,8 @@
 #_(wrapped-with-viewer (clojure.java.io/file "notebooks"))
 #_(wrapped-with-viewer (md "# Hello"))
 #_(wrapped-with-viewer (html [:h1 "hi"]))
-#_(wrapped-with-viewer (with-viewer* :elision {:remaining 10 :count 30 :offset 19}))
-#_(wrapped-with-viewer (with-viewer* (->Form '(fn [name] (html [:<> "Hello " name]))) "James"))
+#_(wrapped-with-viewer (with-viewer :elision {:remaining 10 :count 30 :offset 19}))
+#_(wrapped-with-viewer (with-viewer (->Form '(fn [name] (html [:<> "Hello " name]))) "James"))
 
 (defn get-viewers
   "Returns all the viewers that apply in precendence of: optional local `viewers`, viewers set per `ns`, as well on the `:root`."
@@ -346,7 +320,16 @@
 #_(sequence (drop+take-xf {}) (range 9))
 
 
-(declare with-viewer* assign-closing-parens)
+(declare with-viewer assign-closing-parens)
+
+(defn process-viewer [viewer]
+  (if-not (map? viewer)
+    viewer
+    (cond-> (dissoc viewer :pred :transform-fn :fetch-fn)
+      (:render-fn viewer)
+      (update :render-fn ->Form))))
+
+#_(process-viewer {:render-fn '(v/html [:h1]) :fetch-fn fetch-all})
 
 (defn describe
   "Returns a subset of a given `value`."
@@ -354,7 +337,7 @@
    (describe xs {}))
   ([xs opts]
    (assign-closing-parens
-    (describe xs (merge {:!budget (atom (:budget opts 200)) :path [] :viewers (process-fns (get-viewers *ns* (viewers xs)))} opts) [])))
+    (describe xs (merge {:!budget (atom (:budget opts 200)) :path [] :viewers (get-viewers *ns* (viewers xs))} opts) [])))
   ([xs opts current-path]
    (let [{:as opts :keys [!budget viewers path offset]} (merge {:offset 0} opts)
          wrapped-value (try (wrapped-with-viewer xs viewers) ;; TODO: respect `viewers` on `xs`
@@ -371,7 +354,7 @@
        (swap! !budget #(max (dec %) 0)))
      (merge {:path path}
             (dissoc wrapped-value [:nextjournal/value :nextjournal/viewer])
-            (with-viewer* (cond-> viewer (map? viewer) (dissoc viewer :pred :transform-fn))
+            (with-viewer (process-viewer viewer)
               (cond descend?
                     (let [idx (first (drop (count current-path) path))]
                       (describe (cond (or (map? xs) (set? xs)) (nth (seq (ensure-sorted xs)) idx)
@@ -389,7 +372,7 @@
                                 new-offset (min (+ offset (:n fetch-opts)) total)
                                 remaining (- total new-offset)]
                             (cond-> [(subs xs offset new-offset)]
-                              (pos? remaining) (conj (with-viewer* :elision {:path path :count total :offset new-offset :remaining remaining}))
+                              (pos? remaining) (conj (with-viewer :elision {:path path :count total :offset new-offset :remaining remaining}))
                               true wrap-value
                               true (assoc :replace-path (conj path offset))))
                           xs))
@@ -413,7 +396,7 @@
                       (cond-> children
                         (or (not count) (< (inc offset) count))
 
-                        (conj (with-viewer* :elision
+                        (conj (with-viewer :elision
                                 (cond-> (assoc count-opts :offset (inc offset) :path path)
                                   count (assoc :remaining (- count (inc offset))))))))
 
@@ -431,11 +414,11 @@
   (describe (map vector (range)))
   (describe (subs (slurp "/usr/share/dict/words") 0 1000))
   (describe (plotly {:data [{:z [[1 2 3] [3 2 1]] :type "surface"}]}))
-  (describe (with-viewer* :html [:h1 "hi"]))
-  (describe (with-viewer* :html [:ul (for [x (range 3)] [:li x])]))
+  (describe (with-viewer :html [:h1 "hi"]))
+  (describe (with-viewer :html [:ul (for [x (range 3)] [:li x])]))
   (describe (range))
   (describe {1 [2]})
-  (describe (with-viewer* (->Form '(fn [name] (html [:<> "Hello " name]))) "James")))
+  (describe (with-viewer (->Form '(fn [name] (html [:<> "Hello " name]))) "James")))
 
 (defn desc->values
   "Takes a `description` and returns its value. Inverse of `describe`. Mostly useful for debugging."
@@ -450,7 +433,7 @@
               (map desc->values))))))
 
 #_(desc->values (describe [1 [2 {:a :b} 2] 3 (range 100)]))
-#_(desc->values (describe (with-viewer* :table (normalize-table-data (repeat 60 ["Adelie" "Biscoe" 50 30 200 5000 :female])))))
+#_(desc->values (describe (with-viewer :table (normalize-table-data (repeat 60 ["Adelie" "Biscoe" 50 30 200 5000 :female])))))
 
 (defn path-to-value [path]
   (conj (interleave path (repeat :nextjournal/value)) :nextjournal/value))
@@ -503,16 +486,17 @@
 #_(datafy-scope *ns*)
 #_(datafy-scope #'datafy-scope)
 
-(declare with-viewer*)
+(declare with-viewer)
 
 #?(:clj
-   (defn set-viewers!* [scope viewers]
-     (assert (or (#{:root} scope)
-                 (instance? clojure.lang.Namespace scope)
-                 (var? scope)))
-     (let [viewers (process-fns viewers)]
-       (swap! !viewers assoc scope viewers)
-       (with-viewer* :eval! `'(v/set-viewers! ~(datafy-scope scope) ~viewers)))))
+   (defn set-viewers!
+     ([viewers] (set-viewers! *ns* viewers))
+     ([scope viewers]
+      (assert (or (#{:root} scope)
+                  (instance? clojure.lang.Namespace scope)
+                  (var? scope)))
+      (swap! !viewers assoc scope viewers)
+      (with-viewer :eval! `'(v/set-viewers! ~(datafy-scope scope) ~viewers)))))
 
 
 (defn registration? [x]
@@ -524,7 +508,7 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; public api
 
-(defn with-viewer*
+(defn with-viewer
   "Wraps given "
   [viewer x]
   (-> x
@@ -533,25 +517,25 @@
 
 #_(with-viewer- :latex "x^2")
 
-(defn with-viewers*
+(defn with-viewers
   "Binds viewers to types, eg {:boolean view-fn}"
   [viewers x]
   (-> x
       wrap-value
       (assoc :nextjournal/viewers viewers)))
 
-#_(->> "x^2" (with-viewer* :latex) (with-viewers* [{:name :latex :render-fn :mathjax}]))
+#_(->> "x^2" (with-viewer :latex) (with-viewers [{:name :latex :render-fn :mathjax}]))
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; public convience api
-(def html         (partial with-viewer* :html))
-(def md           (partial with-viewer* :markdown))
-(def plotly       (partial with-viewer* :plotly))
-(def vl           (partial with-viewer* :vega-lite))
-(def tex          (partial with-viewer* :latex))
-(def hide-result  (partial with-viewer* :hide-result))
-(def notebook     (partial with-viewer* :clerk/notebook))
+(def html         (partial with-viewer :html))
+(def md           (partial with-viewer :markdown))
+(def plotly       (partial with-viewer :plotly))
+(def vl           (partial with-viewer :vega-lite))
+(def tex          (partial with-viewer :latex))
+(def hide-result  (partial with-viewer :hide-result))
+(def notebook     (partial with-viewer :clerk/notebook))
 
 (defn table
   "Displays `xs` in a table.
@@ -566,8 +550,8 @@
    (table {:nextjournal/width :wide} xs))
   ([opts xs]
    (-> (if-let [normalized (normalize-table-data xs)]
-         (with-viewer* :table normalized)
-         (with-viewer* :table-error [xs]))
+         (with-viewer :table normalized)
+         (with-viewer :table-error [xs]))
        (merge opts)
        (update :nextjournal/viewers concat (:table @!viewers)))))
 
@@ -576,6 +560,6 @@
 #_(describe (table (set (range 10))))
 
 (defn code [x]
-  (with-viewer* :code (if (string? x) x (with-out-str (pprint/pprint x)))))
+  (with-viewer :code (if (string? x) x (with-out-str (pprint/pprint x)))))
 
 #_(code '(+ 1 2))

From 29a078cabf321f68816244cbaa08b524d81a1600 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 08:47:15 +0100
Subject: [PATCH 02/10] Fix all devcards

---
 src/nextjournal/clerk/viewer.cljc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/nextjournal/clerk/viewer.cljc b/src/nextjournal/clerk/viewer.cljc
index ee5f60983..695997dbc 100644
--- a/src/nextjournal/clerk/viewer.cljc
+++ b/src/nextjournal/clerk/viewer.cljc
@@ -327,7 +327,7 @@
     viewer
     (cond-> (dissoc viewer :pred :transform-fn :fetch-fn)
       (:render-fn viewer)
-      (update :render-fn ->Form))))
+      (update :render-fn #?(:clj ->Form :cljs *eval*)))))
 
 #_(process-viewer {:render-fn '(v/html [:h1]) :fetch-fn fetch-all})
 

From bfc874d1329483d58855bd257537ff97ff5317e2 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 09:24:36 +0100
Subject: [PATCH 03/10] Better names

---
 src/nextjournal/clerk/sci_viewer.cljs | 30 +++++++--------
 src/nextjournal/clerk/viewer.cljc     | 54 +++++++++++++--------------
 2 files changed, 40 insertions(+), 44 deletions(-)

diff --git a/src/nextjournal/clerk/sci_viewer.cljs b/src/nextjournal/clerk/sci_viewer.cljs
index f3d574e67..20f812779 100644
--- a/src/nextjournal/clerk/sci_viewer.cljs
+++ b/src/nextjournal/clerk/sci_viewer.cljs
@@ -95,8 +95,8 @@
          :read-cond :allow
          :readers {'file (partial with-viewer :file)
                    'object (partial with-viewer :object)
-                   'function+ viewer/form->fn+form
-                   'sci-eval viewer/sci-eval}
+                   'viewer-fn viewer/->viewer-fn
+                   'sci-eval *eval*}
          :features #{:clj}}))
 
 (defn ^:export read-string [s]
@@ -414,15 +414,17 @@
 
 (declare default-viewers)
 
+
 (defn maybe-eval [render-fn]
-  (js/console.log :maybe-eval render-fn :eval? (or (symbol? render-fn) (list? render-fn)))
-  (cond-> render-fn
-    (or (symbol? render-fn) (list? render-fn))
-    *eval*))
+  (if (or (symbol? render-fn) (list? render-fn))
+    (do
+      (js/console.log :needs-eval render-fn)
+      (*eval* render-fn))
+    render-fn))
 
 (defn render-with-viewer [{:as opts :keys [viewers]} viewer value]
-  (js/console.log :render-with-viewer {:value value :viewer viewer #_#_ :opts opts})
-  (cond (or (fn? viewer) (viewer/fn+form? viewer))
+  #_(js/console.log :render-with-viewer {:value value :viewer viewer #_#_ :opts opts})
+  (cond (or (fn? viewer) (viewer/viewer-fn? viewer))
         (viewer value opts)
 
         (and (map? viewer) (:render-fn viewer))
@@ -447,7 +449,6 @@
          {:as opts :keys [viewers]} (assoc opts :viewers (vec (concat (viewer/viewers x) viewers)))
          all-viewers (viewer/get-viewers (:scope @!doc) viewers)
          opts (update opts :recursion inc)]
-     (js/console.log :inspect value)
      (or (when (< 20 recursion) [:span "reached recursion limit"])
          (when (react/isValidElement value) value)
          ;; TODO find option to disable client-side viewer selection
@@ -644,7 +645,7 @@
 
 (dc/defcard eval-viewer
   "Viewers that are lists are evaluated using sci."
-  [inspect (with-viewer (viewer/form->fn+form '(fn [x] (v/html [:h3 "Ohai, " x "! 👋"]))) "Hans")])
+  [inspect (with-viewer (viewer/->viewer-fn '(fn [x] (v/html [:h3 "Ohai, " x "! 👋"]))) "Hans")])
 
 
 (dc/defcard notebook
@@ -673,11 +674,11 @@
   [inspect {:path []
             :viewers
             [{:pred number?
-              :render-fn (viewer/form->fn+form '#(v/html [:div.inline-block {:style {:width 16 :height 16}
-                                                                             :class (if (pos? %) "bg-black" "bg-white border-solid border-2 border-
+              :render-fn (viewer/->viewer-fn '#(v/html [:div.inline-block {:style {:width 16 :height 16}
+                                                                           :class (if (pos? %) "bg-black" "bg-white border-solid border-2 border-
 black")}]))}
-             {:pred vector? :render-fn (viewer/form->fn+form '#(v/html (into [:div.flex.inline-flex] (v/inspect-children %2) %1)))}
-             {:pred list? :render-fn (viewer/form->fn+form '#(v/html (into [:div.flex.flex-col] (v/inspect-children %2) %1)))}]}
+             {:pred vector? :render-fn (viewer/->viewer-fn '#(v/html (into [:div.flex.inline-flex] (v/inspect-children %2) %1)))}
+             {:pred list? :render-fn (viewer/->viewer-fn '#(v/html (into [:div.flex.flex-col] (v/inspect-children %2) %1)))}]}
    '([0 1 0] [1 0 1])])
 
 (dc/defcard clj-long
@@ -885,7 +886,6 @@ black")}]))}
   (html (katex/to-html-string tex-string)))
 
 (defn html-viewer [markup]
-  (js/console.log :html-viewer markup)
   (if (string? markup)
     (html [:div {:dangerouslySetInnerHTML {:__html markup}}])
     (r/as-element markup)))
diff --git a/src/nextjournal/clerk/viewer.cljc b/src/nextjournal/clerk/viewer.cljc
index 695997dbc..b6161fd36 100644
--- a/src/nextjournal/clerk/viewer.cljc
+++ b/src/nextjournal/clerk/viewer.cljc
@@ -5,44 +5,35 @@
             #?@(:clj [[clojure.repl :refer [demunge]]
                       [nextjournal.clerk.config :as config]]
                 :cljs [[reagent.ratom :as ratom]]))
-  #?(:clj (:import [clojure.lang IFn]
-                   [java.lang Throwable])))
+  #?(:clj (:import [java.lang Throwable])))
 
-(defrecord Form [form])
 (defrecord SCIEval [form])
-(defrecord Fn+Form [form fn]
-  IFn
-  (#?(:clj invoke :cljs -invoke) [this x]
-    ((:fn this) x))
-  (#?(:clj invoke :cljs -invoke) [this x y]
-    ((:fn this) x y)))
+(defrecord ViewerFn [form #?(:cljs f)]
+  #?@(:cljs [IFn
+             (-invoke [this x] ((:f this) x))
+             (-invoke [this x y] ((:f this) x y))]))
 
 
-(defn fn+form? [x]
-  (instance? Fn+Form x))
+(defn viewer-fn? [x]
+  (instance? ViewerFn x))
 
-(defn form->fn+form
-  ([form]
-   (map->Fn+Form {:form form :fn (#?(:clj eval :cljs *eval*) form)})))
+(defn ->viewer-fn [form]
+  (map->ViewerFn {:form form :f #?(:clj nil :cljs (*eval* form))}))
 
 #?(:cljs (defn sci-eval [form] (*eval* form)))
 
 #?(:clj
-   (defmethod print-method Fn+Form [v ^java.io.Writer w]
-     (.write w (str "#function+ " (pr-str `~(:form v))))))
-
-#?(:clj
-   (defmethod print-method Form [v ^java.io.Writer w]
-     (.write w (str "#function+ " (pr-str `~(:form v))))))
+   (defmethod print-method ViewerFn [v ^java.io.Writer w]
+     (.write w (str "#viewer-fn " (pr-str `~(:form v))))))
 
 #?(:clj
    (defmethod print-method SCIEval [v ^java.io.Writer w]
      (.write w (str "#sci-eval " (pr-str `~(:form v))))))
 
-#_(binding [*data-readers* {'function+ form->fn+form}]
-    (read-string (pr-str (form->fn+form '(fn [x] x)))))
-#_(binding [*data-readers* {'function+ form->fn+form}]
-    (read-string (pr-str (form->fn+form 'number?))))
+#_(binding [*data-readers* {'viewer-fn ->viewer-fn}]
+    (read-string (pr-str (->viewer-fn '(fn [x] x)))))
+#_(binding [*data-readers* {'viewer-fn ->viewer-fn}]
+    (read-string (pr-str (->viewer-fn 'number?))))
 
 (comment
   (def num? (form->fn+form 'number?))
@@ -220,7 +211,7 @@
    {:pred number? :render-fn '(fn [x] (v/html [:span.tabular-nums (if (js/Number.isNaN x) "NaN" (str x))]))}])
 
 (def all-viewers
-  {:root default-viewers
+  {:root  default-viewers
    :table default-table-cell-viewers})
 
 (defonce
@@ -265,7 +256,7 @@
            (if-let [{:as named-viewer :keys [transform-fn]} (find-named-viewer viewers selected-viewer)]
              (wrap-value (cond-> x transform-fn transform-fn) named-viewer)
              (throw (ex-info (str "cannot find viewer named " selected-viewer) {:selected-viewer selected-viewer :x (value x) :viewers viewers})))
-           (instance? Form selected-viewer)
+           (viewer-fn? selected-viewer)
            (wrap-value x selected-viewer))
      (let [val (value x)]
        (loop [v viewers]
@@ -322,12 +313,17 @@
 
 (declare with-viewer assign-closing-parens)
 
+(defn process-render-fn [{:as viewer :keys [render-fn]}]
+  (cond-> viewer
+    (and render-fn (not (viewer-fn? render-fn)))
+    (update :render-fn ->viewer-fn)))
+
 (defn process-viewer [viewer]
   (if-not (map? viewer)
     viewer
-    (cond-> (dissoc viewer :pred :transform-fn :fetch-fn)
-      (:render-fn viewer)
-      (update :render-fn #?(:clj ->Form :cljs *eval*)))))
+    (-> viewer
+        (dissoc :pred :transform-fn :fetch-fn)
+        process-render-fn)))
 
 #_(process-viewer {:render-fn '(v/html [:h1]) :fetch-fn fetch-all})
 

From 77ba1c6f7b5570999dd1aa656a9b5ceb7c80ce9a Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 10:38:38 +0100
Subject: [PATCH 04/10] Preprocess viewer fns & drop maybe-eval

---
 src/nextjournal/clerk/sci_viewer.cljs | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/src/nextjournal/clerk/sci_viewer.cljs b/src/nextjournal/clerk/sci_viewer.cljs
index 20f812779..3adb01f15 100644
--- a/src/nextjournal/clerk/sci_viewer.cljs
+++ b/src/nextjournal/clerk/sci_viewer.cljs
@@ -414,27 +414,19 @@
 
 (declare default-viewers)
 
-
-(defn maybe-eval [render-fn]
-  (if (or (symbol? render-fn) (list? render-fn))
-    (do
-      (js/console.log :needs-eval render-fn)
-      (*eval* render-fn))
-    render-fn))
-
 (defn render-with-viewer [{:as opts :keys [viewers]} viewer value]
   #_(js/console.log :render-with-viewer {:value value :viewer viewer #_#_ :opts opts})
   (cond (or (fn? viewer) (viewer/viewer-fn? viewer))
         (viewer value opts)
 
         (and (map? viewer) (:render-fn viewer))
-        (render-with-viewer opts (maybe-eval (:render-fn viewer)) value)
+        (render-with-viewer opts (:render-fn viewer) value)
 
         (keyword? viewer)
         (if-let [{:keys [fetch-opts render-fn]} (viewer/find-named-viewer viewers viewer)]
           (if-not render-fn
             (html (error-badge "no render function for viewer named " (str viewer)))
-            ((maybe-eval render-fn) value (assoc opts :fetch-opts fetch-opts)))
+            (render-fn value (assoc opts :fetch-opts fetch-opts)))
           (html (error-badge "cannot find viewer named " (str viewer))))
 
         :else
@@ -634,7 +626,6 @@
       [inspect @!error]])])
 
 (defn ^:export set-state [{:as state :keys [doc error]}]
-  (js/console.log :set-state state)
   (doseq [cell (viewer/value doc)
           :when (viewer/registration? cell)
           :let [form (viewer/value cell)]]
@@ -981,3 +972,7 @@ black")}]))}
   (sci/eval-form @!sci-ctx f))
 
 (set! *eval* eval-form)
+
+(swap! viewer/!viewers (fn [viewers]
+                         (-> (into {} (map (juxt key (comp #(into [] (map viewer/process-render-fn) %)  val))) viewers)
+                             (update :root concat js-viewers))))

From 17aa68f6745bf844262d5aed45261770d9c567f6 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 10:51:33 +0100
Subject: [PATCH 05/10] Better ViewerEval name

---
 src/nextjournal/clerk.clj             |  2 +-
 src/nextjournal/clerk/sci_viewer.cljs |  5 ++---
 src/nextjournal/clerk/viewer.cljc     | 15 ++++++++++-----
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/nextjournal/clerk.clj b/src/nextjournal/clerk.clj
index ff9a1ae40..abe685a5e 100644
--- a/src/nextjournal/clerk.clj
+++ b/src/nextjournal/clerk.clj
@@ -239,7 +239,7 @@
 (def table          #'v/table)
 (def use-headers    #'v/use-headers)
 (def hide-result    #'v/hide-result)
-(defn doc-url [path] (v/->SCIEval (list 'v/doc-url path)))
+(def doc-url        #'v/doc-url)
 (def with-viewer    #'v/with-viewer)
 (def with-viewers   #'v/with-viewers)
 (def set-viewers!   #'v/set-viewers!)
diff --git a/src/nextjournal/clerk/sci_viewer.cljs b/src/nextjournal/clerk/sci_viewer.cljs
index 3adb01f15..e28c6fd5c 100644
--- a/src/nextjournal/clerk/sci_viewer.cljs
+++ b/src/nextjournal/clerk/sci_viewer.cljs
@@ -96,7 +96,7 @@
          :readers {'file (partial with-viewer :file)
                    'object (partial with-viewer :object)
                    'viewer-fn viewer/->viewer-fn
-                   'sci-eval *eval*}
+                   'viewer-eval *eval*}
          :features #{:clj}}))
 
 (defn ^:export read-string [s]
@@ -391,8 +391,7 @@
   [:span.inspected-value.whitespace-nowrap
    [:span.syntax-tag tag] value])
 
-(defn normalize-viewer
-  [x]
+(defn normalize-viewer [x]
   (if-let [viewer (-> x meta :nextjournal/viewer)]
     (with-viewer viewer x)
     x))
diff --git a/src/nextjournal/clerk/viewer.cljc b/src/nextjournal/clerk/viewer.cljc
index b6161fd36..d26cc6abd 100644
--- a/src/nextjournal/clerk/viewer.cljc
+++ b/src/nextjournal/clerk/viewer.cljc
@@ -4,10 +4,11 @@
             [clojure.datafy :as datafy]
             #?@(:clj [[clojure.repl :refer [demunge]]
                       [nextjournal.clerk.config :as config]]
-                :cljs [[reagent.ratom :as ratom]]))
+                :cljs [[reagent.ratom :as ratom]])
+            [nextjournal.clerk.viewer :as v])
   #?(:clj (:import [java.lang Throwable])))
 
-(defrecord SCIEval [form])
+(defrecord ViewerEval [form])
 (defrecord ViewerFn [form #?(:cljs f)]
   #?@(:cljs [IFn
              (-invoke [this x] ((:f this) x))
@@ -20,15 +21,16 @@
 (defn ->viewer-fn [form]
   (map->ViewerFn {:form form :f #?(:clj nil :cljs (*eval* form))}))
 
-#?(:cljs (defn sci-eval [form] (*eval* form)))
+(defn ->viewer-eval [form]
+  (map->ViewerEval {:form form}))
 
 #?(:clj
    (defmethod print-method ViewerFn [v ^java.io.Writer w]
      (.write w (str "#viewer-fn " (pr-str `~(:form v))))))
 
 #?(:clj
-   (defmethod print-method SCIEval [v ^java.io.Writer w]
-     (.write w (str "#sci-eval " (pr-str `~(:form v))))))
+   (defmethod print-method ViewerEval [v ^java.io.Writer w]
+     (.write w (str "#viewer-eval " (pr-str `~(:form v))))))
 
 #_(binding [*data-readers* {'viewer-fn ->viewer-fn}]
     (read-string (pr-str (->viewer-fn '(fn [x] x)))))
@@ -532,6 +534,9 @@
 (def tex          (partial with-viewer :latex))
 (def hide-result  (partial with-viewer :hide-result))
 (def notebook     (partial with-viewer :clerk/notebook))
+(defn doc-url [path]
+  (->viewer-eval (list 'v/doc-url path)))
+
 
 (defn table
   "Displays `xs` in a table.

From 85d04b422fb19632095d16b07c2a0b8514cd0049 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 11:18:07 +0100
Subject: [PATCH 06/10] Fix image notebook

---
 notebooks/viewers/image.clj | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/notebooks/viewers/image.clj b/notebooks/viewers/image.clj
index 26131fd28..7aa9b964b 100644
--- a/notebooks/viewers/image.clj
+++ b/notebooks/viewers/image.clj
@@ -10,7 +10,7 @@
 (clerk/set-viewers! [{:pred bytes?
                       :fetch-fn (fn [_ bytes] {:nextjournal/content-type "image/png"
                                                :nextjournal/value bytes})
-                      :render-fn (fn [blob] (v/html [:img {:src (v/url-for blob)}]))}])
+                      :render-fn '(fn [blob] (v/html [:img {:src (v/url-for blob)}]))}])
 
 (.. (HttpClient/newHttpClient)
     (send (.build (HttpRequest/newBuilder (URI. "https://upload.wikimedia.org/wikipedia/commons/5/57/James_Clerk_Maxwell.png")))

From c084fb02b3a1413e7dc16f6142e228e6b9c35640 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 11:21:12 +0100
Subject: [PATCH 07/10] Nix require

---
 src/nextjournal/clerk/viewer.cljc | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/nextjournal/clerk/viewer.cljc b/src/nextjournal/clerk/viewer.cljc
index d26cc6abd..aff91fdca 100644
--- a/src/nextjournal/clerk/viewer.cljc
+++ b/src/nextjournal/clerk/viewer.cljc
@@ -4,8 +4,7 @@
             [clojure.datafy :as datafy]
             #?@(:clj [[clojure.repl :refer [demunge]]
                       [nextjournal.clerk.config :as config]]
-                :cljs [[reagent.ratom :as ratom]])
-            [nextjournal.clerk.viewer :as v])
+                :cljs [[reagent.ratom :as ratom]]))
   #?(:clj (:import [java.lang Throwable])))
 
 (defrecord ViewerEval [form])

From a4aa4c74ea23aecde15b2d2f0f8fd44ea2a5db77 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 15:41:52 +0100
Subject: [PATCH 08/10] Fix with-viewer

---
 notebooks/dice.clj                | 12 ++++++------
 notebooks/viewer_api.clj          |  2 +-
 src/nextjournal/clerk/viewer.cljc |  7 +++++--
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/notebooks/dice.clj b/notebooks/dice.clj
index 233d9ecd7..a16a36196 100644
--- a/notebooks/dice.clj
+++ b/notebooks/dice.clj
@@ -11,12 +11,12 @@
 
 ;; Here, we define a viewer using hiccup that will the dice as well as a button. Note that this button has an `:on-click` event handler that uses `v/clerk-eval` to tell Clerk to evaluate the argument, in this cases `(roll!)` when clicked.
 ^::clerk/no-cache
-(clerk/with-viewer (fn [side]
-                     (v/html [:div.text-center
-                              (when side
-                                [:div.mt-2 {:style {:font-size "6em"}} side])
-                              [:button.bg-blue-500.hover:bg-blue-700.text-white.font-bold.py-2.px-4.rounded
-                               {:on-click (fn [e] (v/clerk-eval '(roll!)))} "Roll 🎲!"]]))
+(clerk/with-viewer '(fn [side]
+                      (v/html [:div.text-center
+                               (when side
+                                 [:div.mt-2 {:style {:font-size "6em"}} side])
+                               [:button.bg-blue-500.hover:bg-blue-700.text-white.font-bold.py-2.px-4.rounded
+                                {:on-click (fn [e] (v/clerk-eval '(roll!)))} "Roll 🎲!"]]))
   @dice)
 
 ;; Our roll! function `resets!` our `dice` with a random side and prints and says the result. Finally it updates the notebook.
diff --git a/notebooks/viewer_api.clj b/notebooks/viewer_api.clj
index a27ceb910..d9ba8fe89 100644
--- a/notebooks/viewer_api.clj
+++ b/notebooks/viewer_api.clj
@@ -50,7 +50,7 @@
 
 ;; ## 🚀 Extensibility
 (clerk/with-viewer '#(v/html [:div "Greetings to " [:strong %] "!"])
-  "James Maxwell Clerk")
+  "James Clerk Maxwell")
 
 (clerk/with-viewers [{:pred number? :render-fn '#(v/html [:div.inline-block [(keyword (str "h" %)) (str "Heading " %)]])}]
   [1 2 3 4 5])
diff --git a/src/nextjournal/clerk/viewer.cljc b/src/nextjournal/clerk/viewer.cljc
index aff91fdca..2bc9b9f97 100644
--- a/src/nextjournal/clerk/viewer.cljc
+++ b/src/nextjournal/clerk/viewer.cljc
@@ -510,9 +510,12 @@
   [viewer x]
   (-> x
       wrap-value
-      (assoc :nextjournal/viewer viewer)))
+      (assoc :nextjournal/viewer (cond-> viewer
+                                   (or (list? viewer) (symbol? viewer))
+                                   ->viewer-fn))))
 
-#_(with-viewer- :latex "x^2")
+#_(with-viewer :latex "x^2")
+#_(with-viewer '#(v/html [:h3 "Hello " % "!"]) "x^2")
 
 (defn with-viewers
   "Binds viewers to types, eg {:boolean view-fn}"

From 9448cb637223dae840bae2a544000eda736e96a9 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 15:54:42 +0100
Subject: [PATCH 09/10] Drop debug recursion limit

---
 src/nextjournal/clerk/sci_viewer.cljs | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/nextjournal/clerk/sci_viewer.cljs b/src/nextjournal/clerk/sci_viewer.cljs
index e28c6fd5c..91fee7da3 100644
--- a/src/nextjournal/clerk/sci_viewer.cljs
+++ b/src/nextjournal/clerk/sci_viewer.cljs
@@ -434,14 +434,12 @@
 (defn inspect
   ([x]
    (r/with-let [!expanded-at (r/atom {})]
-     [inspect {:!expanded-at !expanded-at :recursion 0} x]))
-  ([{:as opts :keys [viewers recursion]} x]
+     [inspect {:!expanded-at !expanded-at} x]))
+  ([{:as opts :keys [viewers]} x]
    (let [value (viewer/value x)
          {:as opts :keys [viewers]} (assoc opts :viewers (vec (concat (viewer/viewers x) viewers)))
-         all-viewers (viewer/get-viewers (:scope @!doc) viewers)
-         opts (update opts :recursion inc)]
-     (or (when (< 20 recursion) [:span "reached recursion limit"])
-         (when (react/isValidElement value) value)
+         all-viewers (viewer/get-viewers (:scope @!doc) viewers)]
+     (or (when (react/isValidElement value) value)
          ;; TODO find option to disable client-side viewer selection
          (when-let [viewer (or (viewer/viewer x)
                                (viewer/viewer (viewer/wrapped-with-viewer value all-viewers)))]

From ac9dee5f814b62c3f9bc3df17883c9f849e18895 Mon Sep 17 00:00:00 2001
From: Martin Kavalar <mk@katercalling.com>
Date: Thu, 13 Jan 2022 19:39:26 +0100
Subject: [PATCH 10/10] Remove obsolete forward declarations

---
 src/nextjournal/clerk/viewer.cljc | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/src/nextjournal/clerk/viewer.cljc b/src/nextjournal/clerk/viewer.cljc
index 2bc9b9f97..c8ee21085 100644
--- a/src/nextjournal/clerk/viewer.cljc
+++ b/src/nextjournal/clerk/viewer.cljc
@@ -145,15 +145,11 @@
 
 (def elide-string-length 100)
 
-(declare with-viewer)
-
 (defn fetch-all [_ x] x)
 
 (defn- var-from-def? [x]
   (get x :nextjournal.clerk/var-from-def))
 
-(declare !viewers)
-
 ;; keep viewer selection stricly in Clojure
 (def default-viewers
   ;; maybe make this a sorted-map