Fix: escaping characters <, >

src/printbox-md/PrintBox_md.ml

@@ -92,12 +92,23 @@ let break_lines l =
       else Some s)
     lines
 
-let pp_string_nbsp ~tab_width ~code_block ~code_quote ~infix out s =
+let pp_string_nbsp ~tab_width ~code_block ~code_quote ~html ~infix out s =
+  (* TODO: benchmark if writing to a buffer first would be more efficient. *)
   let open Format in
   if code_block then pp_print_string out s
   else
     let print_sp nbsp =
       pp_print_string out (if nbsp then " " else " ") in
+    let print_char =
+      if html then
+        fun c ->
+          pp_print_string out @@
+          match c with '<' -> "&lt;" | '>' -> "&gt;" | '&' -> "&amp;" | c -> String.make 1 c
+      else
+        fun c ->
+          pp_print_string out @@
+          (* TODO: consider extending this list, but maybe we shouldn't be too eager? *)
+          match c with '<' -> "\\<" | '>' -> "\\>" | '*' -> "\\*" | c -> String.make 1 c in
     let len = String.length s in
     let check i = i < len && (s.[i] = ' ' || s.[i] = '\t') in
     let i = ref 0 in
@@ -113,10 +124,11 @@ let pp_string_nbsp ~tab_width ~code_block ~code_quote ~infix out s =
       k := !i;
       if code_quote then (
         i := len;
+        (* TODO: escape the backtick `. *)
         pp_print_string out @@ String.sub s !k (len - !k);)
       else (
-        while !i < len && (not @@ check !i) do incr i done;
-        if !k < len then pp_print_string out @@ String.sub s !k (!i - !k);
+        while !i < len && (not @@ check !i) do print_char s.[!i]; incr i done;
+        (* if !k < len then pp_print_string out @@ String.sub s !k (!i - !k); *)
       )
     done
 
@@ -134,7 +146,6 @@ let rec multiline_heuristic b =
     Array.length children > 0 || multiline_heuristic header
   | B.Link {inner; _} -> multiline_heuristic inner
   
-
 let pp c out b =
   let open Format in
   (* We cannot use Format for indentation, because we need to insert ">" at the right places. *)
@@ -146,7 +157,8 @@ let pp c out b =
       let multiline = List.length l > 1 in
       let sty_pre, sty_post, code_block, code_quote, inline =
         style_format c ~in_span ~multiline style in
-      let preformat = pp_string_nbsp ~tab_width:c.Config.tab_width ~code_block ~code_quote in
+      let preformat =
+        pp_string_nbsp ~tab_width:c.Config.tab_width ~code_block ~code_quote ~html:in_span in
       pp_print_string out sty_pre;
       if not inline && String.length sty_pre > 0 then fprintf out "@,%s" prefix;
       if code_block then fprintf out "```@,%s" prefix;

src/printbox-md/playground.md

@@ -177,3 +177,5 @@ Trying this <pre>one-line code</pre> is not inline.
 multiline<br>
 &nbsp;&nbsp;code line 1<br>
 &nbsp; code line 2</span>
+
+What happens with <returns> say & also `<returns>` html-ish syntax? &lt; and &gt; -- hmm &amp; only if it's &something; recognized?

test/test_md.expected

@@ -10,7 +10,9 @@ Test default:
   >   - > subchild 3
 - 
   - > header 4
-    - subchild 4
+    - \<returns\>
+      - `<nothing>`
+    - & \*subchild\* 4
 - > `header 5`
   > - ```
   >   subchild 5
@@ -54,7 +56,9 @@ Test uniform unfolded:
   </div>
 - 
   - <span style="border:thin solid">header 4</span>
-    - subchild 4
+    - \<returns\>
+      - <span style="font-family: monospace">\<nothing\></span>
+    - & \*subchild\* 4
 - <div style="border:thin solid">
 
   <span style="font-family: monospace">header 5</span>
@@ -130,7 +134,11 @@ Test foldable:
 
   - <details><summary><span style="border:thin solid">header 4</span></summary>
 
-    - subchild 4
+    - <details><summary>&lt;returns&gt;</summary>
+
+      - `<nothing>`
+      </details>
+    - & \*subchild\* 4
     </details>
   </details>
 - > <details><summary><span style="font-family: monospace">header 5</span></summary>
@@ -185,7 +193,11 @@ Test uniform tab=2, text tables:
 
   - <details><summary><span style="border:thin solid">header 4</span></summary>
 
-    - subchild 4
+    - <details><summary>&lt;returns&gt;</summary>
+
+      - <span style="font-family: monospace">\<nothing\></span>
+      </details>
+    - & \*subchild\* 4
     </details>
   </details>
 - <div style="border:thin solid">
@@ -247,7 +259,11 @@ Test single quote tab=2, text tables:
 
   - <details><summary><span style="border:thin solid">header 4</span></summary>
 
-    - subchild 4
+    - <details><summary>&lt;returns&gt;</summary>
+
+      - <span style="font-family: monospace">\<nothing\></span>
+      </details>
+    - & \*subchild\* 4
     </details>
   </details>
 - <div style="border:thin solid">

test/test_md.expected.md

@@ -10,7 +10,9 @@ Test default:
   >   - > subchild 3
 - 
   - > header 4
-    - subchild 4
+    - \<returns\>
+      - `<nothing>`
+    - & \*subchild\* 4
 - > `header 5`
   > - ```
   >   subchild 5
@@ -54,7 +56,9 @@ Test uniform unfolded:
   </div>
 - 
   - <span style="border:thin solid">header 4</span>
-    - subchild 4
+    - \<returns\>
+      - <span style="font-family: monospace">\<nothing\></span>
+    - & \*subchild\* 4
 - <div style="border:thin solid">
 
   <span style="font-family: monospace">header 5</span>
@@ -130,7 +134,11 @@ Test foldable:
 
   - <details><summary><span style="border:thin solid">header 4</span></summary>
 
-    - subchild 4
+    - <details><summary>&lt;returns&gt;</summary>
+      
+      - `<nothing>`
+      </details>
+    - & \*subchild\* 4
     </details>
   </details>
 - > <details><summary><span style="font-family: monospace">header 5</span></summary>
@@ -185,7 +193,11 @@ Test uniform tab=2, text tables:
 
   - <details><summary><span style="border:thin solid">header 4</span></summary>
 
-    - subchild 4
+    - <details><summary>&lt;returns&gt;</summary>
+      
+      - <span style="font-family: monospace">\<nothing\></span>
+      </details>
+    - & \*subchild\* 4
     </details>
   </details>
 - <div style="border:thin solid">
@@ -247,7 +259,11 @@ Test single quote tab=2, text tables:
 
   - <details><summary><span style="border:thin solid">header 4</span></summary>
 
-    - subchild 4
+    - <details><summary>&lt;returns&gt;</summary>
+      
+      - <span style="font-family: monospace">\<nothing\></span>
+      </details>
+    - & \*subchild\* 4
     </details>
   </details>
 - <div style="border:thin solid">

test/test_md.ml

@@ -15,7 +15,9 @@ let b =
       tree (frame @@ text "header 3") [frame @@ text "subchild 3"]
     ];
     tree empty [
-      tree (frame @@ text "header 4") [text "subchild 4"]
+      tree (frame @@ text "header 4") [
+        tree (text "<returns>") [text_with_style Style.preformatted "<nothing>"];
+        text "& *subchild* 4"]
     ];
     frame @@ tree (text_with_style Style.preformatted "header 5")
       [lines_with_style Style.preformatted