feat(literate): add +literate/find-heading command

A command for jumping to an Org heading in your literate org config
file.

Close: #7716

modules/config/default/+evil-bindings.el

@@ -485,6 +485,8 @@
        :desc "Browse emacs.d"              "E"   #'doom/browse-in-emacsd
        :desc "Find file"                   "f"   #'find-file
        :desc "Find file from here"         "F"   #'+default/find-file-under-here
+       (:when (modulep! :config literate)
+         :desc "Open heading in literate config" "h" #'+literate/find-heading)
        :desc "Locate file"                 "l"   #'locate
        :desc "Find file in private config" "p"   #'doom/find-file-in-private-config
        :desc "Browse private config"       "P"   #'doom/open-private-config

modules/config/literate/autoload.el

@@ -106,6 +106,41 @@
 ;;;###autoload
 (defalias '+literate/reload #'doom/reload)
 
+(defun +literate--flatten-imenu-index (index &optional prefix)
+  "Flatten an org-mode imenu index."
+  (let ((flattened '()))
+    (dolist (item index flattened)
+      (let* ((name (propertize (car item) 'face (intern (format "org-level-%d" (if prefix (+ 2 (cl-count ?/ prefix)) 1)))))
+             (prefix (if prefix (concat prefix "/" name) name)))
+        (if (imenu--subalist-p item)
+            (setq flattened (append flattened (+literate--flatten-imenu-index (cdr item) prefix)))
+          (push (cons prefix (cdr item)) flattened))))
+    (nreverse flattened)))
+
+(defvar imenu-auto-rescan)
+;;;###autoload
+(defun +literate/find-heading (&optional level)
+  "Jump to a heading in your literate org config file."
+  (interactive "P")
+  (let* ((buffer (or (find-buffer-visiting +literate-config-file)
+                     (find-file-noselect +literate-config-file t))))
+    (with-current-buffer buffer
+      (let* ((imenu-auto-rescan t)
+             (org-imenu-depth (or level 8))
+             (index (+literate--flatten-imenu-index (imenu--make-index-alist))))
+        (let ((c (current-window-configuration))
+              (result nil))
+          (unwind-protect
+              (progn
+                (switch-to-buffer buffer)
+                (if (modulep! :completion vertico)
+                    (setq result (consult-outline level))
+                  (let ((entry (assoc (completing-read "Go to heading: " index nil t) index)))
+                    (setq result entry)
+                    (imenu entry))))
+            (unless result
+              (set-window-configuration c))))))))
+
 
 ;;
 ;;; Hooks