From 79cf209204b083d03269223cdb4c839868185eb1 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Fri, 2 Sep 2022 11:38:04 +0200
Subject: [PATCH 01/13] Transform Markdown data back to text

---
 src/nextjournal/markdown/parser.cljc    |   9 +-
 src/nextjournal/markdown/transform.cljc | 230 +++++++++++++++++++++++-
 2 files changed, 232 insertions(+), 7 deletions(-)

diff --git a/src/nextjournal/markdown/parser.cljc b/src/nextjournal/markdown/parser.cljc
index 43285f3..292cfe0 100644
--- a/src/nextjournal/markdown/parser.cljc
+++ b/src/nextjournal/markdown/parser.cljc
@@ -103,7 +103,8 @@
 (defn tag-node [text] {:type :hashtag :text text})
 (defn formula [text] {:type :formula :text text})
 (defn block-formula [text] {:type :block-formula :text text})
-(defn sidenote-ref [ref] {:type :sidenote-ref :content [(text-node (str (inc ref)))]})
+(defn sidenote-data [token] {:ref (get-in* token [:meta :id])
+                             :label (get-in* token [:meta :label])})
 
 ;; node constructors
 (defn node
@@ -279,9 +280,11 @@ end"
       close-node))
 
 ;; footnotes
-(defmethod apply-token "sidenote_ref" [doc token] (push-node doc (sidenote-ref (get-in* token [:meta :id]))))
+(defmethod apply-token "sidenote_ref" [doc token] (push-node doc (assoc (sidenote-data token) :type :sidenote-ref) ))
 (defmethod apply-token "sidenote_anchor" [doc token] doc)
-(defmethod apply-token "sidenote_open" [doc token] (-> doc (assoc :sidenotes? true) (open-node :sidenote {:ref (get-in* token [:meta :id])})))
+(defmethod apply-token "sidenote_open" [doc token] (-> doc
+                                                       (assoc :sidenotes? true)
+                                                       (open-node :sidenote nil (sidenote-data token))))
 (defmethod apply-token "sidenote_close" [doc token] (close-node doc))
 (defmethod apply-token "sidenote_block_open" [doc token] (-> doc (assoc :sidenotes? true) (open-node :sidenote {:ref (get-in* token [:meta :id])})))
 (defmethod apply-token "sidenote_block_close" [doc token] (close-node doc))
diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index ee5b2cf..2f1d7f3 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -1,7 +1,9 @@
 (ns nextjournal.markdown.transform
   "transform markdown data as returned by `nextjournal.markdown/parse` into other formats, currently:
      * hiccup"
-  (:require [lambdaisland.uri.normalize :as uri.normalize]))
+  {:nextjournal.clerk/visibility {:code :hide :result :hide}}
+  (:require [lambdaisland.uri.normalize :as uri.normalize]
+            [clojure.string :as str]))
 
 ;; helpers
 (defn guard [pred val] (when (pred val) val))
@@ -108,9 +110,9 @@ a paragraph
    :table-data (fn [ctx {:as node :keys [attrs]}] (into-markup [:td {:style (table-alignment attrs)}] ctx node))
 
    ;; sidenodes
-   :sidenote-ref (partial into-markup [:sup.sidenote-ref])
-   :sidenote (fn [ctx {:as node :keys [attrs]}]
-               (into-markup [:span.sidenote [:sup {:style {:margin-right "3px"}} (-> attrs :ref inc)]]
+   :sidenote-ref (fn [_ {:keys [ref]}] [:sup.sidenote-ref (str (inc ref))])
+   :sidenote (fn [ctx {:as node :keys [ref]}]
+               (into-markup [:span.sidenote [:sup {:style {:margin-right "3px"}} (str (inc ref))]]
                             ctx
                             node))
    ;; TOC
@@ -194,3 +196,223 @@ par two"
                      ;; wrap something around the default
                      :paragraph (fn [{:as ctx d :default} node] [:div.p-container (d ctx node)]))))
   )
+
+;; Text Transform
+(defn write [ctx & strs] (update ctx ::buf into strs))
+
+;; ctx -> node -> ctx
+(defn write-node [ctx {:as node :keys [type]}]
+  (if-some [handler (get ctx type)]
+    (handler ctx node)
+    (throw (ex-info (str "unhandled node type: " type) {:node node}))))
+
+(defn write-child-nodes [ctx node]
+  (update (reduce write-node (update ctx ::parents conj (:type node)) (:content node))
+          ::parents pop))
+
+;; {node ->} str
+(def new-line "\n")
+(def block-end "\n\n")
+(def code-fence "```")
+(defn code-fence+info [_ {:keys [language]}] (str code-fence language new-line))
+(def tab "indent unit" "  ")
+(defn heading-marker [_ {:keys [heading-level]}]
+  (str (str/join (repeat heading-level "#")) " "))
+
+;; handler -> handler
+(defn ?->fn [m] (cond-> m (not (fn? m)) constantly))
+(defn before [bf f] (fn [ctx n] (f (write ctx ((?->fn bf) ctx n)) n)))
+(defn after [af f] (fn [ctx n]
+                     (let [ctx' (f ctx n)]
+                       (write ctx' ((?->fn af) ctx' n)))))
+
+(defn block [f] (after block-end f))
+
+;; nest children
+(defn prepend-to-child-nodes [bf] (before bf write-child-nodes))
+(defn append-to-child-nodes [af] (after af write-child-nodes))
+(defn wrap-child-nodes [bf af] (after af (before bf write-child-nodes)))
+(defn wrap-mark [m] (wrap-child-nodes m m))
+
+(def top? (comp #{:doc} peek ::parents))
+(defn quote? [{::keys [parents]}] (some #{:blockquote} parents))
+(defn list-container [{::keys [parents]}] (some #{:bullet-list :numbered-list} parents))
+(defn write-list-padding [{:as ctx ::keys [parents]}]
+  (apply write ctx (repeat (dec (count (keep #{:bullet-list :numbered-list :todo-list} parents))) tab)))
+
+(defn write-list [ctx n]
+  (-> ctx
+      (write-child-nodes n)
+      (cond-> (top? ctx) (write new-line))))
+
+(defn item-marker [{:as ctx ::keys [item-number]}]
+  (case (list-container ctx)
+    :bullet-list "* "
+    :numbered-list (str item-number ". ")))
+
+(defn write-sidenote [ctx {:as node :keys [label]}]
+  (-> ctx (write "[^" label "]: ") (write-child-nodes node) (write new-line)))
+
+(def default-md-renderers
+  {:doc write-child-nodes
+   :toc (fn [ctx n] ctx)                              ;; ignore toc
+   :text (fn [ctx {:keys [text]}] (write ctx text))
+   :heading (block (prepend-to-child-nodes heading-marker))
+   :ruler (block (fn [ctx _] (write ctx "---")))
+   :paragraph (block
+               (prepend-to-child-nodes
+                (fn [ctx _] (when (quote? ctx) "> "))))
+   :plain (append-to-child-nodes new-line)
+   :softbreak (fn [ctx _]
+                (-> ctx
+                    (write new-line)
+                    (cond-> (list-container ctx) (-> write-list-padding (write "  ")))
+                    (cond-> (quote? ctx) (write "> "))))
+   :blockquote write-child-nodes
+
+   :formula (fn [ctx {:keys [text]}] (write ctx (str "$" text "$")))
+   :block-formula (block (fn [ctx {:keys [text]}] (write ctx (str "$$" (str/trim text) "$$"))))
+
+   ;; marks
+   :em (wrap-mark "_")
+   :strong (wrap-mark "**")
+   :monospace (wrap-mark "`")
+   :strikethrough (wrap-mark "~~")
+   :hashtag (fn [ctx {:keys [text]}] (write ctx (str \# text)))
+   :link (fn [ctx {:as n :keys [attrs]}]
+           (-> ctx
+               (write "[")
+               (write-child-nodes n)
+               (write "](" (:href attrs) ")")))
+   :internal-link (fn [ctx {:keys [text]}] (write ctx "[[" text "]]"))
+
+   :code (block (wrap-child-nodes code-fence+info code-fence))
+
+   ;; lists
+   :bullet-list write-list
+   :numbered-list (fn [ctx n]
+                    (-> ctx
+                        (assoc ::item-number (-> n :attrs (:start 1)))
+                        (write-list n)
+                        (dissoc ::item-number)))
+   :todo-list write-list
+   :list-item (fn [{:as ctx ::keys [item-number]} n]
+                (-> ctx
+                    (cond-> item-number (update ::item-number inc))
+                    write-list-padding
+                    (write (item-marker ctx))
+                    (write-child-nodes n)))
+   :todo-item (fn [ctx {:as n :keys [attrs]}]
+                (-> ctx
+                    write-list-padding
+                    (write (str "- [" (if (:checked attrs) "x" " ") "] "))
+                    (write-child-nodes n)))
+
+   :image (fn [{:as ctx ::keys [parents]} {:as n :keys [attrs]}]
+            (-> ctx
+                (write "![")
+                (write-child-nodes n)
+                (write "](" (:src attrs) ")")
+                (cond-> (top? ctx) (write block-end))))
+
+   :sidenote-ref (fn [ctx {:keys [label]}] (write ctx "[^" label "]"))
+   :sidenote (fn [ctx n] (update ctx ::sidenotes conj n))
+   })
+
+(defn ->md
+  ([doc] (->md default-md-renderers doc))
+  ([{:as ctx ::keys [sidenotes]} doc]
+   (as-> ctx c
+     (write-node c doc)
+     (reduce write-sidenote c (reverse sidenotes))
+     (str (str/trim (apply str (reverse (::buf c)))) "\n"))))
+
+(comment
+  (do
+    (def doc (nextjournal.markdown/parse "# Ahoi
+this is *just* a __strong__ ~~text~~ with a $\\phi$ and a #hashtag
+
+this is an ![inline-image](/some/src) and a [_link_](/foo/bar)
+
+par with a sidenote at the end[^sidenote] and another[^sn2] somewhere
+
+```clojure
+(+ 1 2)
+```
+
+$$
+\\int_a^b\\phi(t)dt
+$$
+
+* _this_
+
+  * sub1
+  * sub2 some bla
+    bla bla
+* is not
+
+  2. nsub1
+  3. nsub2
+  4. nsub3
+* thight
+  - [ ] undone
+  - [x] done
+* > and
+  > a nice
+  > quote
+
+![block *image*](/some/src)
+
+> so what
+> is this
+
+1. one
+2. two
+---
+
+another
+
+[^sidenote]: Here a __description__
+[^sn2]: And some _other_
+"))
+
+    (-> doc
+        ->md
+        #_ nextjournal.markdown/parse
+        ))
+
+
+  (nextjournal.markdown/parse "
+this is ![alt](/the/hell/is/you \"hey\") inline")
+  (nextjournal.markdown/parse "
+[_alt_](/the/hell/is/you)")
+
+  (nextjournal.markdown/parse "
+par with a sidenote at the end[^sidenote] and another[^sn2] somewhere
+
+[^sidenote]: some desc
+[^sn2]: some other desc
+")
+
+  (nextjournal.markdown/parse "
+a [_link text_](/foo/bar) and a sn [^sidenote]
+
+[^sidenote]: what a __description__")
+
+  (nextjournal.markdown/tokenize "
+a [_link text_](/foo/bar) and a sn")
+
+  (nextjournal.markdown/tokenize "
+a [_link_](/foo/bar) link and a sidenote at the end[^sidenote]
+
+[^sidenote]: what a sn")
+
+  (nextjournal.markdown/parse "
+* foo bar
+  bla bla
+* and what
+* > is this
+  > for a
+  > nice quote")
+
+  )

From ae09abea4262346b58fb45de0f0845e996bd9633 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Wed, 28 Sep 2022 14:23:11 +0200
Subject: [PATCH 02/13] Add notebook

---
 notebooks/clerk_to_markdown.clj | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 notebooks/clerk_to_markdown.clj

diff --git a/notebooks/clerk_to_markdown.clj b/notebooks/clerk_to_markdown.clj
new file mode 100644
index 0000000..f522fda
--- /dev/null
+++ b/notebooks/clerk_to_markdown.clj
@@ -0,0 +1,29 @@
+;; # 🗜 Clerk to Markdown
+(ns clerk_to_markdown
+  (:require [nextjournal.clerk :as clerk]
+            [nextjournal.clerk.parser :as clerk.parser]
+            [nextjournal.markdown.transform :as md.transform]))
+
+;; This notebook shows how to transform a Clojure namespace with Clerk style _literal fragments_ into a [markdown](https://daringfireball.net/projects/markdown/) file.
+
+(def this-notebook "notebooks/clerk_to_markdown.clj")
+
+;; A clerk notebook is composed of blocks, of type `:markdown` and `:code`. With recent additions to the markdown library we can turn our markdown AST data back into markdown text.
+
+;; This function turns a Clerk block into a string
+
+(defn block->md [{:as block :keys [type text doc]}]
+  (case type
+    :code (str "```clojure\n" text "\n```\n\n")
+    :markdown (md.transform/->md doc)))
+
+;; to put everything together, parse this notebook with Clerk and emit markdown as follows.
+
+^{::clerk/viewer '(fn [s _] (v/html [:pre s]))}
+(->> this-notebook
+     (clerk.parser/parse-file {:doc? true})
+     :blocks
+     (map block->md)
+     (apply str))
+
+;; To learn more about clerk visit our [github page](https://github.com/nextjournal/clerk).

From 10d01b478b7b2ee864d9ea6d49be5c0a483cafb4 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Wed, 28 Sep 2022 14:44:48 +0200
Subject: [PATCH 03/13] Fix sidenotes / Add test

---
 deps.edn                                      |  1 +
 src/nextjournal/markdown/transform.cljc       | 21 +++++--
 test/nextjournal/markdown/transform_test.cljc | 62 +++++++++++++++++++
 3 files changed, 78 insertions(+), 6 deletions(-)
 create mode 100644 test/nextjournal/markdown/transform_test.cljc

diff --git a/deps.edn b/deps.edn
index a8e3d1d..326bab0 100644
--- a/deps.edn
+++ b/deps.edn
@@ -17,6 +17,7 @@
                        "notebooks/pandoc.clj"
                        "notebooks/parsing_extensibility.clj"
                        "notebooks/benchmarks.clj"
+                       "notebooks/clerk_to_markdown.clj"
                        "notebooks/tight_lists.clj"]}}
 
   :quiet
diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index 2f1d7f3..44ead0c 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -321,10 +321,10 @@ par two"
 
 (defn ->md
   ([doc] (->md default-md-renderers doc))
-  ([{:as ctx ::keys [sidenotes]} doc]
+  ([ctx doc]
    (as-> ctx c
      (write-node c doc)
-     (reduce write-sidenote c (reverse sidenotes))
+     (reduce write-sidenote c (reverse (::sidenotes c)))
      (str (str/trim (apply str (reverse (::buf c)))) "\n"))))
 
 (comment
@@ -349,14 +349,17 @@ $$
   * sub1
   * sub2 some bla
     bla bla
+
 * is not
 
   2. nsub1
   3. nsub2
   4. nsub3
+
 * thight
   - [ ] undone
   - [x] done
+
 * > and
   > a nice
   > quote
@@ -376,10 +379,16 @@ another
 [^sn2]: And some _other_
 "))
 
-    (-> doc
-        ->md
-        #_ nextjournal.markdown/parse
-        ))
+
+    (->md doc )
+
+    (::buf (write-node default-md-renderers doc))
+
+
+    (def doc2 (-> doc ->md nextjournal.markdown/parse))
+    (= (:content doc) (= (:content doc2)))
+    doc
+    doc2)
 
 
   (nextjournal.markdown/parse "
diff --git a/test/nextjournal/markdown/transform_test.cljc b/test/nextjournal/markdown/transform_test.cljc
new file mode 100644
index 0000000..a4b05ff
--- /dev/null
+++ b/test/nextjournal/markdown/transform_test.cljc
@@ -0,0 +1,62 @@
+(ns nextjournal.markdown.transform-test
+  (:require #?(:clj [clojure.test :refer :all]
+               :cljs [cljs.test :refer (deftest testing is)])
+            [matcher-combinators.test]
+            [nextjournal.markdown :as md]
+            [nextjournal.markdown.transform :as md.transform]))
+
+(def test-text "# Ahoi
+this is *just* a __strong__ ~~text~~ with a $\\phi$ and a #hashtag
+
+this is an ![inline-image](/some/src) and a [_link_](/foo/bar)
+
+par with a sidenote at the end[^sidenote] and another[^sn2] somewhere
+
+```clojure
+(+ 1 2)
+```
+
+$$\\int_a^b\\phi(t)dt$$
+
+* _this_
+
+  * sub1
+  * sub2 some bla
+    bla bla
+
+* is not
+
+  2. nsub1
+  3. nsub2
+  4. nsub3
+
+* thight
+  - [ ] undone
+  - [x] done
+
+* > and
+  > a nice
+  > quote
+
+![block *image*](/some/src)
+
+> so what
+> is this
+
+1. one
+2. two
+---
+
+another
+
+[^sidenote]: Here a __description__
+[^sn2]: And some _other_
+")
+
+(deftest ->md
+  (let [doc (md/parse test-text)]
+
+    (is (= doc
+           (-> doc
+               md.transform/->md
+               md/parse)))))

From 4f97dd7a23ae81b4dc6642e0eb480ae62ccca563 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Wed, 28 Sep 2022 17:16:07 +0200
Subject: [PATCH 04/13] Transform tables

---
 src/nextjournal/markdown/transform.cljc       | 106 +++++++++---------
 test/nextjournal/markdown/transform_test.cljc |   8 ++
 2 files changed, 63 insertions(+), 51 deletions(-)

diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index 44ead0c..68af974 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -253,6 +253,43 @@ par two"
 (defn write-sidenote [ctx {:as node :keys [label]}]
   (-> ctx (write "[^" label "]: ") (write-child-nodes node) (write new-line)))
 
+(declare ->md)
+(defn process-table-cell [ctx node]
+  (-> node (select-keys [:attrs]) (assoc :text (str/trim (->md (dissoc ctx ::buf ::sidenotes) node)))))
+
+(defn write-row [col-widths ctx row]
+  (as-> ctx c
+    (write c "|")
+    (reduce-kv (fn [ctx i {:as cell :keys [text]}]
+                 (as-> ctx c
+                   (write c " ")
+                   (write c text)
+                   (apply write c (repeat (- (col-widths i) (count text)) " "))
+                   (write c " |"))) c (vec row))
+    (write c new-line)))
+
+(defn write-head-line [col-widths ctx row]
+  (as-> ctx c
+    (write c "|")
+    (reduce-kv (fn [ctx i {{:keys [style]} :attrs}]
+                 (as-> ctx c
+                   (write c (if (#{"text-align:center" "text-align:left"} style) ":" "-"))
+                   (apply write c (repeat (col-widths i) "-"))
+                   (write c (if (#{"text-align:center" "text-align:right"} style) ":" "-") "|"))) c (vec row))
+    (write c new-line)))
+
+(defn write-table [{:as ctx ::keys [table]}]
+  (def table table)
+  (let [[head & body :as rows] (:rows table)
+        column-widths (mapv (fn [i] (apply max (map (comp count :text #(nth % i)) rows)))
+                            (range (count (first rows))))]
+    (as-> ctx c
+      (write-row column-widths c head)
+      (write-head-line column-widths c head)
+      (reduce (partial write-row column-widths) c body)
+      (write c new-line))))
+
+;; md text renderers
 (def default-md-renderers
   {:doc write-child-nodes
    :toc (fn [ctx n] ctx)                              ;; ignore toc
@@ -317,7 +354,15 @@ par two"
 
    :sidenote-ref (fn [ctx {:keys [label]}] (write ctx "[^" label "]"))
    :sidenote (fn [ctx n] (update ctx ::sidenotes conj n))
-   })
+
+   ;; tables
+   :table (fn [ctx n] (-> ctx (assoc ::table {:rows []}) (write-child-nodes n) write-table (dissoc ::table)))
+   :table-head write-child-nodes
+   :table-body write-child-nodes
+   :table-header write-child-nodes
+   :table-data write-child-nodes
+   :table-row (fn [ctx {:keys [content]}]
+                (update-in ctx [::table :rows] conj (map (partial process-table-cell ctx) content)))})
 
 (defn ->md
   ([doc] (->md default-md-renderers doc))
@@ -327,9 +372,7 @@ par two"
      (reduce write-sidenote c (reverse (::sidenotes c)))
      (str (str/trim (apply str (reverse (::buf c)))) "\n"))))
 
-(comment
-  (do
-    (def doc (nextjournal.markdown/parse "# Ahoi
+#_ (->md (nextjournal.markdown/parse "# Ahoi
 this is *just* a __strong__ ~~text~~ with a $\\phi$ and a #hashtag
 
 this is an ![inline-image](/some/src) and a [_link_](/foo/bar)
@@ -371,57 +414,18 @@ $$
 
 1. one
 2. two
+
 ---
 
 another
 
+| _col1_        | col2                    |
+|:-------------:|:------------------------|
+| whatthasdasfd | hell                    |
+| this is       | insane as as as as as f |
+
+end
+
 [^sidenote]: Here a __description__
 [^sn2]: And some _other_
 "))
-
-
-    (->md doc )
-
-    (::buf (write-node default-md-renderers doc))
-
-
-    (def doc2 (-> doc ->md nextjournal.markdown/parse))
-    (= (:content doc) (= (:content doc2)))
-    doc
-    doc2)
-
-
-  (nextjournal.markdown/parse "
-this is ![alt](/the/hell/is/you \"hey\") inline")
-  (nextjournal.markdown/parse "
-[_alt_](/the/hell/is/you)")
-
-  (nextjournal.markdown/parse "
-par with a sidenote at the end[^sidenote] and another[^sn2] somewhere
-
-[^sidenote]: some desc
-[^sn2]: some other desc
-")
-
-  (nextjournal.markdown/parse "
-a [_link text_](/foo/bar) and a sn [^sidenote]
-
-[^sidenote]: what a __description__")
-
-  (nextjournal.markdown/tokenize "
-a [_link text_](/foo/bar) and a sn")
-
-  (nextjournal.markdown/tokenize "
-a [_link_](/foo/bar) link and a sidenote at the end[^sidenote]
-
-[^sidenote]: what a sn")
-
-  (nextjournal.markdown/parse "
-* foo bar
-  bla bla
-* and what
-* > is this
-  > for a
-  > nice quote")
-
-  )
diff --git a/test/nextjournal/markdown/transform_test.cljc b/test/nextjournal/markdown/transform_test.cljc
index a4b05ff..90f8a80 100644
--- a/test/nextjournal/markdown/transform_test.cljc
+++ b/test/nextjournal/markdown/transform_test.cljc
@@ -45,10 +45,18 @@ $$\\int_a^b\\phi(t)dt$$
 
 1. one
 2. two
+
 ---
 
 another
 
+| _col1_        | col2                    |
+|:-------------:|:------------------------|
+| whatthasdasfd | hell                    |
+| this is       | insane as as as as as f |
+
+end
+
 [^sidenote]: Here a __description__
 [^sn2]: And some _other_
 ")

From c7ce7f692e4f45b23ca1391fed0a489e366f2915 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Thu, 29 Sep 2022 18:16:30 +0200
Subject: [PATCH 05/13] Add transformation of a Markdown notebook to Clerk
 clojure namespace

---
 notebooks/clerk_to_markdown.clj | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/notebooks/clerk_to_markdown.clj b/notebooks/clerk_to_markdown.clj
index f522fda..079b07d 100644
--- a/notebooks/clerk_to_markdown.clj
+++ b/notebooks/clerk_to_markdown.clj
@@ -1,6 +1,8 @@
 ;; # 🗜 Clerk to Markdown
 (ns clerk_to_markdown
-  (:require [nextjournal.clerk :as clerk]
+  {:nextjournal.clerk/no-cache true}
+  (:require [clojure.string :as str]
+            [nextjournal.clerk :as clerk]
             [nextjournal.clerk.parser :as clerk.parser]
             [nextjournal.markdown.transform :as md.transform]))
 
@@ -10,7 +12,7 @@
 
 ;; A clerk notebook is composed of blocks, of type `:markdown` and `:code`. With recent additions to the markdown library we can turn our markdown AST data back into markdown text.
 
-;; This function turns a Clerk block into a string
+;; This function turns a Clerk block into a markdown string
 
 (defn block->md [{:as block :keys [type text doc]}]
   (case type
@@ -20,10 +22,26 @@
 ;; to put everything together, parse this notebook with Clerk and emit markdown as follows.
 
 ^{::clerk/viewer '(fn [s _] (v/html [:pre s]))}
-(->> this-notebook
-     (clerk.parser/parse-file {:doc? true})
+(def as-markdown
+  (->> this-notebook
+       (clerk.parser/parse-file {:doc? true})
+       :blocks
+       (map block->md)
+       (apply str)))
+
+;; We can go back to a clojure namespace as follows
+(defn block->clj [{:as block :keys [type text doc]}]
+  (case type
+    :code (str "\n" text "\n")
+    :markdown (apply str
+                     (interleave (repeat ";; ")
+                                 (str/split-lines (md.transform/->md doc))
+                                 (repeat "\n")))))
+
+^{::clerk/viewer '(fn [s _] (v/html [:pre s]))}
+(->> (clerk.parser/parse-markdown-string {:doc? true} as-markdown)
      :blocks
-     (map block->md)
+     (map block->clj)
      (apply str))
 
 ;; To learn more about clerk visit our [github page](https://github.com/nextjournal/clerk).

From 617716cb9fd26cf7fe31d5ea1e0036c17326fb50 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Thu, 29 Sep 2022 18:25:49 +0200
Subject: [PATCH 06/13] Better title

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

diff --git a/notebooks/clerk_to_markdown.clj b/notebooks/clerk_to_markdown.clj
index 079b07d..3dc6f30 100644
--- a/notebooks/clerk_to_markdown.clj
+++ b/notebooks/clerk_to_markdown.clj
@@ -1,4 +1,4 @@
-;; # 🗜 Clerk to Markdown
+;; # 🔄 Clerk to Markdown and Back
 (ns clerk_to_markdown
   {:nextjournal.clerk/no-cache true}
   (:require [clojure.string :as str]

From 22758bad01d33bbea6d232ed44219d4d0a2fe2e1 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Fri, 10 Mar 2023 18:15:07 +0100
Subject: [PATCH 07/13] Bump Clerk

---
 README.md                       | 4 ++--
 deps.edn                        | 4 ++--
 notebooks/clerk_to_markdown.clj | 4 ++--
 notebooks/try.clj               | 8 ++++----
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index 1d52afb..d325c00 100644
--- a/README.md
+++ b/README.md
@@ -93,14 +93,14 @@ We've built hiccup transformation in for convenience, but the same approach can
 This library is one of the building blocks of [Clerk](https://github.com/nextjournal/clerk) where it is used for rendering _literate fragments_.
 
 ```clojure
-^{:nextjournal.clerk/viewer :markdown}
+^{:nextjournal.clerk/viewer 'nextjournal.clerk.viewer/markdown-viewer}
 data
 ```
 
 The transformation of markdown node types can be customised like this:
 
 ```clojure
-^{:nextjournal.clerk/viewer :html}
+^{:nextjournal.clerk/viewer 'nextjournal.clerk.viewer/html-viewer}
 (md.transform/->hiccup
  (assoc md.transform/default-hiccup-renderers
         ;; :doc specify a custom container for the whole doc
diff --git a/deps.edn b/deps.edn
index 1384b1e..0fc4898 100644
--- a/deps.edn
+++ b/deps.edn
@@ -6,7 +6,7 @@
  :aliases
  {:nextjournal/clerk
   {:extra-paths ["notebooks"]
-   :extra-deps {io.github.nextjournal/clerk {:git/sha "60f2399dcdaf39f5d7bc2c213a8dde9a6e0081a9"
+   :extra-deps {io.github.nextjournal/clerk {:git/sha "711a1b2fae3c212d2c8c2323cf4d53c178766114"
                                              :exclusions [io.github.nextjournal/markdown]}}
    :jvm-opts ["-Dclojure.main.report=stderr"
               "-Dclerk.resource_manifest={\"/js/viewer.js\" \"js/viewer.js\"}"] ;;
@@ -40,7 +40,7 @@
    :main-opts ["-m" "shadow.cljs.devtools.cli"]
    :jvm-opts ["-Dclerk.resource_manifest={\"/js/viewer.js\" \"http://localhost:8021/viewer.js\"}"]
    :extra-deps {io.github.nextjournal/clerk.render {:git/url "https://github.com/nextjournal/clerk"
-                                                    :git/sha "bc137cb51ce98236f48d8dfcb420f6e9df3342c1"
+                                                    :git/sha "711a1b2fae3c212d2c8c2323cf4d53c178766114"
                                                     :deps/root "render"}}}
 
   :build
diff --git a/notebooks/clerk_to_markdown.clj b/notebooks/clerk_to_markdown.clj
index 241708d..5ab2c64 100644
--- a/notebooks/clerk_to_markdown.clj
+++ b/notebooks/clerk_to_markdown.clj
@@ -23,7 +23,7 @@
 
 ;; now, to put everything together, parse this notebook with Clerk and emit markdown as follows.
 
-^{::clerk/viewer '(fn [s _] (v/html [:pre s]))}
+^{::clerk/viewer '(fn [s _] (nextjournal.clerk.viewer/html [:pre s]))}
 (def as-markdown
   (->> this-notebook
        (clerk.parser/parse-file {:doc? true})
@@ -40,7 +40,7 @@
                                  (str/split-lines (md.transform/->md doc))
                                  (repeat "\n")))))
 
-^{::clerk/viewer '(fn [s _] (v/html [:pre s]))}
+^{::clerk/viewer '(fn [s _] (nextjournal.clerk.viewer/html [:pre s]))}
 (->> (clerk.parser/parse-markdown-string {:doc? true} as-markdown)
      :blocks
      (map block->clj)
diff --git a/notebooks/try.clj b/notebooks/try.clj
index 1c2d3ba..6ee3255 100644
--- a/notebooks/try.clj
+++ b/notebooks/try.clj
@@ -6,8 +6,8 @@
 ^{::clerk/width :full
   ::clerk/visibility {:code :fold}
   ::clerk/viewer {:render-fn '(fn [_]
-                                (v/html
-                                 (reagent/with-let
+                                (nextjournal.clerk.viewer/html
+                                 (reagent.core/with-let
                                   [init-text "# 👋 Hello Markdown
 
 ```clojure id=xxyyzzww
@@ -19,13 +19,13 @@
 - [ ] _stuff_ here"
                                    text->state (fn [text] (as-> (md/parse text) parsed {:parsed parsed
                                                                                         :hiccup (md.transform/->hiccup md.demo/renderers parsed)}))
-                                   !state (reagent/atom (text->state init-text))
+                                   !state (reagent.core/atom (text->state init-text))
                                    text-update! (fn [text] (reset! !state (text->state text)))]
                                   [:div.grid.grid-cols-2.m-10
                                    [:div.m-2.p-2.text-xl.border-2.overflow-y-scroll.bg-slate-100 {:style {:height "20rem"}} [md.demo/editor {:doc-update text-update! :doc init-text}]]
                                    [:div.m-2.p-2.font-medium.overflow-y-scroll {:style {:height "20rem"}} [md.demo/inspect-expanded (:parsed @!state)]]
                                    [:div.m-2.p-2.overflow-x-scroll [md.demo/inspect-expanded (:hiccup @!state)]]
-                                   [:div.m-2.p-2.bg-slate-50.viewer-markdown [v/html (:hiccup @!state)]]])))}}
+                                   [:div.m-2.p-2.bg-slate-50.viewer-markdown [nextjournal.clerk.viewer/html (:hiccup @!state)]]])))}}
 (Object.)
 
 

From deaa4b047d8c115b947b5018f68af22ce2774ce6 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Fri, 10 Mar 2023 18:20:33 +0100
Subject: [PATCH 08/13] Reorg / improve tests

---
 src/nextjournal/markdown/transform.cljc       | 38 ++++++++++---------
 test/nextjournal/markdown/transform_test.cljc |  4 +-
 2 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index 646693d..10c7765 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -11,6 +11,7 @@
       text
       (apply str (map ->text content))))
 
+;; ## Hiccup Transform
 (defn hydrate-toc
   "Scans doc contents and replaces toc node placeholder with the toc node accumulated during parse."
   [{:as doc :keys [toc]}]
@@ -208,7 +209,7 @@ par two"
                      :paragraph (fn [{:as ctx d :default} node] [:div.p-container (d ctx node)]))))
   )
 
-;; Text Transform
+;; ## Text Transform
 (defn write [ctx & strs] (update ctx ::buf into strs))
 
 ;; ctx -> node -> ctx
@@ -256,10 +257,20 @@ par two"
       (write-child-nodes n)
       (cond-> (top? ctx) (write new-line))))
 
-(defn item-marker [{:as ctx ::keys [item-number]}]
-  (case (list-container ctx)
-    :bullet-list "* "
-    :numbered-list (str item-number ". ")))
+(defn item-marker [{:as ctx ::keys [item-number]} {:keys [type attrs]}]
+  (if (= :todo-item type)
+    (str "- [" (if (:checked attrs) "x" " ") "] ")
+    (case (list-container ctx)
+      :bullet-list "* "
+      :numbered-list (str item-number ". "))))
+
+(defn write-list-item [{:as ctx ::keys [item-number]} n]
+  (-> ctx
+      (cond-> item-number (update ::item-number inc))
+      (cond-> (quote? ctx) (write "> "))
+      write-list-padding
+      (write (item-marker ctx n))
+      (write-child-nodes n)))
 
 (defn write-footnote [ctx {:as node :keys [label ref]}]
   (-> ctx (write "[^" (or label ref) "]: ") (write-child-nodes node) (write new-line)))
@@ -302,7 +313,7 @@ par two"
 
 ;; md text renderers
 (def default-md-renderers
-  {:doc write-child-nodes
+  {:doc (block write-child-nodes)
    :toc (fn [ctx n] ctx)                              ;; ignore toc
    :text (fn [ctx {:keys [text]}] (write ctx text))
    :heading (block (prepend-to-child-nodes heading-marker))
@@ -316,7 +327,7 @@ par two"
                     (write new-line)
                     (cond-> (list-container ctx) (-> write-list-padding (write "  ")))
                     (cond-> (quote? ctx) (write "> "))))
-   :blockquote write-child-nodes
+   :blockquote (block write-child-nodes)
 
    :formula (fn [ctx {:keys [text]}] (write ctx (str "$" text "$")))
    :block-formula (block (fn [ctx {:keys [text]}] (write ctx (str "$$" (str/trim text) "$$"))))
@@ -344,17 +355,8 @@ par two"
                         (write-list n)
                         (dissoc ::item-number)))
    :todo-list write-list
-   :list-item (fn [{:as ctx ::keys [item-number]} n]
-                (-> ctx
-                    (cond-> item-number (update ::item-number inc))
-                    write-list-padding
-                    (write (item-marker ctx))
-                    (write-child-nodes n)))
-   :todo-item (fn [ctx {:as n :keys [attrs]}]
-                (-> ctx
-                    write-list-padding
-                    (write (str "- [" (if (:checked attrs) "x" " ") "] "))
-                    (write-child-nodes n)))
+   :list-item write-list-item
+   :todo-item write-list-item
 
    :image (fn [{:as ctx ::keys [parents]} {:as n :keys [attrs]}]
             (-> ctx
diff --git a/test/nextjournal/markdown/transform_test.cljc b/test/nextjournal/markdown/transform_test.cljc
index 90f8a80..bf5ada7 100644
--- a/test/nextjournal/markdown/transform_test.cljc
+++ b/test/nextjournal/markdown/transform_test.cljc
@@ -55,6 +55,9 @@ another
 | whatthasdasfd | hell                    |
 | this is       | insane as as as as as f |
 
+> * one
+> * two
+
 end
 
 [^sidenote]: Here a __description__
@@ -63,7 +66,6 @@ end
 
 (deftest ->md
   (let [doc (md/parse test-text)]
-
     (is (= doc
            (-> doc
                md.transform/->md

From ca3d8a023c6c1789ad556888eed1603ccf0f9227 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Fri, 14 Apr 2023 15:47:12 +0200
Subject: [PATCH 09/13] Bump graal JS

---
 deps.edn | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/deps.edn b/deps.edn
index 0fc4898..522dfb1 100644
--- a/deps.edn
+++ b/deps.edn
@@ -1,7 +1,7 @@
 {:paths ["src" "resources"]
  :deps {applied-science/js-interop {:mvn/version "0.3.3"}
         org.clojure/data.json {:mvn/version "2.4.0"}
-        org.graalvm.js/js {:mvn/version "21.3.2.1"}}
+        org.graalvm.js/js {:mvn/version "22.3.1"}}
 
  :aliases
  {:nextjournal/clerk

From 3b152ae6da6bd520ec4dcd9dbe56b9cab252958f Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Fri, 14 Apr 2023 17:26:02 +0200
Subject: [PATCH 10/13] Keep markup from markdown tokens

---
 src/nextjournal/markdown.cljs                 |  4 +-
 src/nextjournal/markdown/parser.cljc          | 62 +++++++++++--------
 src/nextjournal/markdown/transform.cljc       | 28 +++++++++
 test/nextjournal/markdown/transform_test.cljc |  6 +-
 test/test_runner.clj                          |  3 +-
 5 files changed, 71 insertions(+), 32 deletions(-)

diff --git a/src/nextjournal/markdown.cljs b/src/nextjournal/markdown.cljs
index 53b851d..77f8636 100644
--- a/src/nextjournal/markdown.cljs
+++ b/src/nextjournal/markdown.cljs
@@ -7,7 +7,9 @@
 
 (extend-type Token
   ILookup
-  (-lookup [this key] (j/get this key)))
+  (-lookup
+    ([this key] (j/get this key))
+    ([this key not-found] (j/get this key not-found))))
 
 (def tokenize md/tokenize)
 
diff --git a/src/nextjournal/markdown/parser.cljc b/src/nextjournal/markdown/parser.cljc
index 1946520..74b5713 100644
--- a/src/nextjournal/markdown/parser.cljc
+++ b/src/nextjournal/markdown/parser.cljc
@@ -135,10 +135,9 @@
 
 ;; node constructors
 (defn node
-  [type content attrs top-level]
+  [type content keyvals]
   (cond-> {:type type :content content}
-    (seq attrs) (assoc :attrs attrs)
-    (seq top-level) (merge top-level)))
+    (seq keyvals) (merge keyvals)))
 
 (defn empty-text-node? [{text :text t :type}] (and (= :text t) (empty? text)))
 
@@ -158,10 +157,9 @@
 
 (defn open-node
   ([doc type] (open-node doc type {}))
-  ([doc type attrs] (open-node doc type attrs {}))
-  ([doc type attrs top-level]
+  ([doc type keyvals]
    (-> doc
-       (push-node (node type [] attrs top-level))
+       (push-node (node type [] keyvals))
        (update ::path into [:content -1]))))
 
 ;; after closing a node, document ::path will point at it
@@ -305,7 +303,7 @@ end"
   doc)
 
 ;; blocks
-(defmethod apply-token "heading_open" [doc token] (open-node doc :heading {} {:heading-level (hlevel token)}))
+(defmethod apply-token "heading_open" [doc token] (open-node doc :heading (assoc (select-keys token [:markup]) :heading-level (hlevel token))))
 (defmethod apply-token "heading_close" [doc {doc-level :level}]
   (let [{:as doc ::keys [path]} (close-node doc)
         doc' (assign-node-id+emoji doc)
@@ -320,13 +318,13 @@ end"
 (defmethod apply-token "paragraph_open" [doc {:as _token :keys [hidden]}] (open-node doc (if hidden :plain :paragraph)))
 (defmethod apply-token "paragraph_close" [doc _token] (close-node doc))
 
-(defmethod apply-token "bullet_list_open" [doc {{:as attrs :keys [has-todos]} :attrs}] (open-node doc (if has-todos :todo-list :bullet-list) attrs))
+(defmethod apply-token "bullet_list_open" [doc {:as token :keys [attrs]}] (open-node doc (if (:has-todos attrs) :todo-list :bullet-list) (select-keys token [:attrs])))
 (defmethod apply-token "bullet_list_close" [doc _token] (close-node doc))
 
-(defmethod apply-token "ordered_list_open" [doc {:keys [attrs]}] (open-node doc :numbered-list attrs))
+(defmethod apply-token "ordered_list_open" [doc token] (open-node doc :numbered-list (select-keys token [:attrs])))
 (defmethod apply-token "ordered_list_close" [doc _token] (close-node doc))
 
-(defmethod apply-token "list_item_open" [doc {{:as attrs :keys [todo]} :attrs}] (open-node doc (if todo :todo-item :list-item) attrs))
+(defmethod apply-token "list_item_open" [doc {:as token :keys [attrs]}] (open-node doc (if (:todo attrs) :todo-item :list-item) (select-keys token [:attrs :markup])))
 (defmethod apply-token "list_item_close" [doc _token] (close-node doc))
 
 (defmethod apply-token "math_block" [doc {text :content}] (push-node doc (block-formula text)))
@@ -341,15 +339,17 @@ end"
 (defmethod apply-token "tocBody" [doc _token] doc) ;; ignore body
 (defmethod apply-token "tocClose" [doc _token] (-> doc close-node (update-current dissoc :content)))
 
-(defmethod apply-token "code_block" [doc {:as _token c :content}]
+(defmethod apply-token "code_block" [doc {:as token :keys [content]}]
   (-> doc
-      (open-node :code)
-      (push-node (text-node c))
+      (open-node :code (select-keys token [:markup]))
+      (push-node (text-node content))
       close-node))
-(defmethod apply-token "fence" [doc {:as _token i :info c :content}]
+(defmethod apply-token "fence" [doc {:as token :keys [info content]}]
   (-> doc
-      (open-node :code {} (assoc (parse-fence-info i) :info i))
-      (push-node (text-node c))
+      (open-node :code (-> (select-keys token [:markup])
+                           (assoc :info info)
+                           (merge (parse-fence-info info))))
+      (push-node (text-node content))
       close-node))
 
 ;; footnotes
@@ -363,7 +363,7 @@ end"
   ;; consider an offset in case we're parsing multiple inputs into the same context
   (let [ref (+ (get-in* token [:meta :id]) footnote-offset)
         label (get-in* token [:meta :label])]
-    (open-node doc :footnote nil (cond-> {:ref ref} label (assoc :label label)))))
+    (open-node doc :footnote (cond-> {:ref ref} label (assoc :label label)))))
 
 (defmethod apply-token "footnote_close" [doc token] (close-node doc))
 
@@ -384,7 +384,7 @@ end"
 
 (defn footnote->sidenote [{:keys [ref label content]}]
   ;; this assumes the footnote container is a paragraph, won't work for lists
-  (node :sidenote (-> content first :content) nil (cond-> {:ref ref} label (assoc :label label))))
+  (node :sidenote (-> content first :content) (cond-> {:ref ref} label (assoc :label label))))
 
 (defn node-with-sidenote-refs [p-node]
   (loop [l (->zip p-node) refs []]
@@ -457,11 +457,11 @@ And what.
 (defmethod apply-token "thead_close" [doc _token] (close-node doc))
 (defmethod apply-token "tr_open" [doc _token] (open-node doc :table-row))
 (defmethod apply-token "tr_close" [doc _token] (close-node doc))
-(defmethod apply-token "th_open" [doc token] (open-node doc :table-header (:attrs token)))
+(defmethod apply-token "th_open" [doc token] (open-node doc :table-header (select-keys token [:attrs])))
 (defmethod apply-token "th_close" [doc _token] (close-node doc))
 (defmethod apply-token "tbody_open" [doc _token] (open-node doc :table-body))
 (defmethod apply-token "tbody_close" [doc _token] (close-node doc))
-(defmethod apply-token "td_open" [doc token] (open-node doc :table-data (:attrs token)))
+(defmethod apply-token "td_open" [doc token] (open-node doc :table-data (select-keys token [:attrs])))
 (defmethod apply-token "td_close" [doc _token] (close-node doc))
 
 (comment
@@ -577,18 +577,25 @@ _this #should be a tag_, but this [_actually #foo shouldnt_](/bar/) is not."
 (defmethod apply-token "hardbreak" [doc _token] (push-node doc {:type :hardbreak}))
 
 ;; images
-(defmethod apply-token "image" [doc {:keys [attrs children]}] (-> doc (open-node :image attrs) (apply-tokens children) close-node))
+(defmethod apply-token "image" [doc {:as token :keys [children]}]
+  (-> doc
+      (open-node :image (select-keys token [:attrs]))
+      (apply-tokens children)
+      close-node))
 
 ;; marks
-(defmethod apply-token "em_open" [doc _token] (open-node doc :em))
+(defmethod apply-token "em_open" [doc token] (open-node doc :em (select-keys token [:markup])))
 (defmethod apply-token "em_close" [doc _token] (close-node doc))
-(defmethod apply-token "strong_open" [doc _token] (open-node doc :strong))
+(defmethod apply-token "strong_open" [doc token] (open-node doc :strong (select-keys token [:markup])))
 (defmethod apply-token "strong_close" [doc _token] (close-node doc))
-(defmethod apply-token "s_open" [doc _token] (open-node doc :strikethrough))
+(defmethod apply-token "s_open" [doc token] (open-node doc :strikethrough (select-keys token [:markup])))
 (defmethod apply-token "s_close" [doc _token] (close-node doc))
-(defmethod apply-token "link_open" [doc token] (open-node doc :link (:attrs token)))
+(defmethod apply-token "link_open" [doc token] (open-node doc :link (select-keys token [:attrs])))
 (defmethod apply-token "link_close" [doc _token] (close-node doc))
-(defmethod apply-token "code_inline" [doc {text :content}] (-> doc (open-node :monospace) (push-node (text-node text)) close-node))
+(defmethod apply-token "code_inline" [doc {:as token :keys [content]}]
+  (-> doc (open-node :monospace (select-keys token [:markup]))
+      (push-node (text-node content))
+      close-node))
 
 ;; html (ignored)
 (defmethod apply-token "html_inline" [doc _] doc)
@@ -737,5 +744,6 @@ some final par"
   (into []
         (comp
          (mapcat (partial tree-seq (comp seq :children) :children))
-         (map #(select-keys % [:type :content :hidden :level :info :meta])))
+         (map (comp #(into {} (filter (comp some? val)) %)
+                    #(select-keys % [:type :content :hidden :level :info :attrs :markup :meta]))))
         tokens))
diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index 10c7765..eccd45b 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -442,3 +442,31 @@ end
 [^sidenote]: Here a __description__
 [^sn2]: And some _other_
 "))
+
+
+(comment
+  ;; nested marks
+  (->md (nextjournal.markdown/parse "
+some *emph around a __strong__* bit"))
+
+
+  ;; preserving markup
+  (->md (nextjournal.markdown/parse "
+Preserve Markup
+---------------
+
+- this _should_ and *could*
+- look **the** __very same__
+"))
+
+  (nextjournal.markdown.parser/flatten-tokens (nextjournal.markdown/tokenize "
+```
+fence
+```
+
+1) one
+2) two
+
+- this _should_ and *could*
+- look **the** __very same__ and ~~why~~
+")))
diff --git a/test/nextjournal/markdown/transform_test.cljc b/test/nextjournal/markdown/transform_test.cljc
index bf5ada7..5d18bc1 100644
--- a/test/nextjournal/markdown/transform_test.cljc
+++ b/test/nextjournal/markdown/transform_test.cljc
@@ -6,7 +6,7 @@
             [nextjournal.markdown.transform :as md.transform]))
 
 (def test-text "# Ahoi
-this is *just* a __strong__ ~~text~~ with a $\\phi$ and a #hashtag
+this is _just_ a **strong** ~~text~~ with a $\\phi$ and a #hashtag
 
 this is an ![inline-image](/some/src) and a [_link_](/foo/bar)
 
@@ -38,7 +38,7 @@ $$\\int_a^b\\phi(t)dt$$
   > a nice
   > quote
 
-![block *image*](/some/src)
+![block _image_](/some/src)
 
 > so what
 > is this
@@ -60,7 +60,7 @@ another
 
 end
 
-[^sidenote]: Here a __description__
+[^sidenote]: Here a _description_
 [^sn2]: And some _other_
 ")
 
diff --git a/test/test_runner.clj b/test/test_runner.clj
index 22e6521..d5b5c48 100644
--- a/test/test_runner.clj
+++ b/test/test_runner.clj
@@ -1,6 +1,7 @@
 (ns test-runner
   (:require [clojure.test]
-            [nextjournal.markdown-test]))
+            [nextjournal.markdown-test]
+            [nextjournal.markdown.transform-test]))
 
 (defn run [_]
   (let [{:keys [fail error]} (clojure.test/run-all-tests #"nextjournal\.markdown.*-test")]

From eb7f8a23f7421104f4142156abd14084d1b8c6bc Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Fri, 14 Apr 2023 17:44:41 +0200
Subject: [PATCH 11/13] A first step toward preserving markup

---
 src/nextjournal/markdown/transform.cljc       | 14 ++++++++++----
 test/nextjournal/markdown/transform_test.cljc | 12 ++++++------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index eccd45b..2e19b36 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -230,6 +230,7 @@ par two"
 (def tab "indent unit" "  ")
 (defn heading-marker [_ {:keys [heading-level]}]
   (str (str/join (repeat heading-level "#")) " "))
+(defn node-markup [default] (fn [_ {:keys [markup]}] (or markup default)))
 
 ;; handler -> handler
 (defn ?->fn [m] (cond-> m (not (fn? m)) constantly))
@@ -244,7 +245,9 @@ par two"
 (defn prepend-to-child-nodes [bf] (before bf write-child-nodes))
 (defn append-to-child-nodes [af] (after af write-child-nodes))
 (defn wrap-child-nodes [bf af] (after af (before bf write-child-nodes)))
-(defn wrap-mark [m] (wrap-child-nodes m m))
+(defn wrap-mark [default-markup] (wrap-child-nodes
+                                  (node-markup default-markup)
+                                  (node-markup default-markup)))
 
 (def top? (comp #{:doc} peek ::parents))
 (defn quote? [{::keys [parents]}] (some #{:blockquote} parents))
@@ -257,12 +260,12 @@ par two"
       (write-child-nodes n)
       (cond-> (top? ctx) (write new-line))))
 
-(defn item-marker [{:as ctx ::keys [item-number]} {:keys [type attrs]}]
+(defn item-marker [{:as ctx ::keys [item-number]} {:keys [type markup attrs]}]
   (if (= :todo-item type)
     (str "- [" (if (:checked attrs) "x" " ") "] ")
     (case (list-container ctx)
-      :bullet-list "* "
-      :numbered-list (str item-number ". "))))
+      :bullet-list (str (or markup "*") " ")
+      :numbered-list (str item-number (or markup ".") " "))))
 
 (defn write-list-item [{:as ctx ::keys [item-number]} n]
   (-> ctx
@@ -457,6 +460,9 @@ Preserve Markup
 
 - this _should_ and *could*
 - look **the** __very same__
+
+1) one
+2) two
 "))
 
   (nextjournal.markdown.parser/flatten-tokens (nextjournal.markdown/tokenize "
diff --git a/test/nextjournal/markdown/transform_test.cljc b/test/nextjournal/markdown/transform_test.cljc
index 5d18bc1..aa8f95e 100644
--- a/test/nextjournal/markdown/transform_test.cljc
+++ b/test/nextjournal/markdown/transform_test.cljc
@@ -6,7 +6,7 @@
             [nextjournal.markdown.transform :as md.transform]))
 
 (def test-text "# Ahoi
-this is _just_ a **strong** ~~text~~ with a $\\phi$ and a #hashtag
+this is *just* a **strong** ~~text~~ with a $\\phi$ and a #hashtag
 
 this is an ![inline-image](/some/src) and a [_link_](/foo/bar)
 
@@ -20,8 +20,8 @@ $$\\int_a^b\\phi(t)dt$$
 
 * _this_
 
-  * sub1
-  * sub2 some bla
+  - sub1
+  - sub2 some bla
     bla bla
 
 * is not
@@ -43,8 +43,8 @@ $$\\int_a^b\\phi(t)dt$$
 > so what
 > is this
 
-1. one
-2. two
+1) one
+2) two
 
 ---
 
@@ -60,7 +60,7 @@ another
 
 end
 
-[^sidenote]: Here a _description_
+[^sidenote]: Here a __description__
 [^sn2]: And some _other_
 ")
 

From bc356f503d6c30925c14aff6f8f32618c3e416ec Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Fri, 14 Apr 2023 17:55:19 +0200
Subject: [PATCH 12/13] Support hard line breaks

---
 src/nextjournal/markdown/transform.cljc | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index 2e19b36..07486ae 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -328,7 +328,13 @@ par two"
    :softbreak (fn [ctx _]
                 (-> ctx
                     (write new-line)
-                    (cond-> (list-container ctx) (-> write-list-padding (write "  ")))
+                    (cond-> (list-container ctx) (-> write-list-padding (write tab)))
+                    (cond-> (quote? ctx) (write "> "))))
+   :hardbreak (fn [ctx _]
+                (-> ctx
+                    (write "\\")
+                    (write new-line)
+                    (cond-> (list-container ctx) (-> write-list-padding (write tab)))
                     (cond-> (quote? ctx) (write "> "))))
    :blockquote (block write-child-nodes)
 

From c1b60ca3a2ecd52a6a26272baea4deb1851c06c2 Mon Sep 17 00:00:00 2001
From: Andrea Amantini <lo.zampino@gmail.com>
Date: Wed, 1 Feb 2023 11:52:06 +0100
Subject: [PATCH 13/13] Typing

---
 src/nextjournal/markdown/transform.cljc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/nextjournal/markdown/transform.cljc b/src/nextjournal/markdown/transform.cljc
index 07486ae..cf9b8d8 100644
--- a/src/nextjournal/markdown/transform.cljc
+++ b/src/nextjournal/markdown/transform.cljc
@@ -314,7 +314,11 @@ par two"
       (reduce (partial write-row column-widths) c body)
       (write c new-line))))
 
-;; md text renderers
+;; ## Markdown Text Renderers
+;; Dispatch on types, holds renderers
+;;
+;;    { Type : Ctx -> Node -> Ctx }
+;;
 (def default-md-renderers
   {:doc (block write-child-nodes)
    :toc (fn [ctx n] ctx)                              ;; ignore toc