Imenu items can now include markdown cells that look like headings.

lisp/ein-cell.el

@@ -203,6 +203,21 @@ a number will limit the number of lines in a cell output."
           (insert-image img ".")))
     (error (ein:log 'warn "Could not insert image: %s" err) nil)))
 
+(defun ein:cell--markdown-heading-p (cell)
+  "Check if cell is behaving like a heading cell.
+
+Returns true if cell is a markdown cell, has at least one # character at the start of the line and is only one line long (i.e. does not contain any newline characters)."
+  (and (ein:markdowncell-p cell)
+       (string-match "^#+ " (ein:cell-get-text cell))
+       (= 0 (seq-count #'(lambda (c)
+                           (char-equal c ?\n))
+                       (ein:cell-get-text cell)))))
+
+(cl-defmethod ein:cell--markdown-heading-level ((cell ein:markdowncell))
+  (progn
+    (string-match "^#+" (ein:cell-get-text cell))
+    (match-end 0)))
+
 
 ;;; Cell factory
 
@@ -227,6 +242,7 @@ a number will limit the number of lines in a cell output."
 (defun ein:cell-from-type (type &rest args)
   (apply (ein:cell-class-from-type type) args))
 
+
 (defun ein:cell--determine-cell-type (json-data)
   (let ((base-type (plist-get json-data :cell_type))
         (metadata (plist-get json-data :metadata)))

lisp/ein-worksheet.el

@@ -1326,12 +1326,20 @@ function."
   ;; As Imenu does not provide the way to represent level *and*
   ;; position, use #'s to do that.
   (cl-loop for cell in (when (ein:worksheet-p ein:%worksheet%)
-                         (seq-filter #'ein:headingcell-p
+                         (seq-filter #'(lambda (cell) (or (ein:headingcell-p cell)
+                                                          (ein:cell--markdown-heading-p cell)))
                                      (ein:worksheet-get-cells ein:%worksheet%)))
-    for sharps = (cl-loop repeat (slot-value cell 'level) collect "#")
-    for text = (ein:cell-get-text cell)
-    for name = (ein:join-str "" (append sharps (list " " text)))
-    collect (cons name (ein:cell-input-pos-min cell))))
+           for sharps = (if (ein:headingcell-p cell)
+                            (cl-loop repeat (slot-value cell 'level) collect "#")
+                          (cl-loop repeat(progn
+                                           (string-match "^#+" (ein:cell-get-text cell))
+                                           (match-end 0))
+                                   collect "#"))
+           for text = (ein:cell-get-text cell)
+           for name = (if (ein:headingcell-p cell)
+                          (ein:join-str "" (append sharps (list " " text)))
+                        text)
+           collect (cons name (ein:cell-input-pos-min cell))))
 
 (defun ein:worksheet-imenu-setup ()
   "Called via notebook mode hooks."