First working version

bdio-mode.el

+;;; bdio-mode.el --- View .bdio files using lsbdio
+(require 's)
+
+(defvar bdio-mode-hook nil)
+
+(defun bdio--render-file (file)
+  "Render FILE using lsbdio into current buffer."
+  (let ((inhibit-read-only t))
+    (erase-buffer)
+    (let ((exit-code
+	   (call-process "lsbdio" nil t nil file "-c 0")))
+      (unless (eq exit-code 0)
+	(insert (format "Error running lsbdio on %s\n" file))))
+    (goto-char (point-min))
+    (while (re-search-forward "^\\([0-9]+\\)\\s-" nil t)
+      (let ((record (string-to-number (match-string 1))))
+	(put-text-property
+	 (line-beginning-position)
+	 (line-end-position)
+	 'bdio-record record)
+	))))
+
+(defun bdio-open-file ()
+  "Open .bdio file using lsbdio."
+  (let ((file (buffer-file-name)))
+    (when file
+      (rename-buffer
+       (format "*BDIO* %s" (file-name-nondirectory file)) t)
+      ;(set-visited-file-name nil t)
+      (bdio-mode)
+      (bdio--render-file file)
+      (set-buffer-modified-p nil))))
+
+(defun get-properties ()
+  (interactive)
+  (let ((properties (text-properties-at (point))))
+    (while properties
+      (print (car properties))
+      (setq properties (cdr properties)))))
+
+;; (defun bdio-revert-buffer (_ignore-auto _noconfirm)
+;;   (bdio--render-file buffer-file-name))
+
+(defun bdio-toggle-record ()
+  "Expand/collapse current record."
+  (interactive)
+  (setq bdio-file buffer-file-name)
+  (setq lstart (line-beginning-position)
+	lend (line-end-position)
+	cpoint (point))
+
+  (let* ((record (get-text-property lstart 'bdio-record))
+	 (inhibit-read-only t))
+    (when record
+      (if (get-text-property lstart 'bdio-expanded)
+	  (let ((start (line-end-position))
+		(end (+ (next-single-property-change
+		      (line-end-position)
+		      'bdio-record
+		      nil
+		      (point-max)) -1) ))
+	    (delete-region start  end)
+	    (put-text-property lstart lend 'bdio-expanded nil))
+	(let ()
+	  (end-of-line)
+	  (insert "\n")
+	  (let ((output-start (point)))
+	    ;; insert command output
+	  (call-process "lsbdio"  nil t nil bdio-file "-d" (number-to-string record)))
+	    ;; mark inserted region
+	  (put-text-property lstart lend 'bdio-expanded t)))))
+  (goto-char cpoint))
+;;               ;; optional face
+;;               (add-text-properties
+;;                output-start
+;;                (point)
+;;                '(face shadow)))))))))
+
+(setq-local revert-buffer-function #'bdio-revert-buffer)
+
+
+;;;###autoload
+(add-to-list 'auto-mode-alist '("\\.bdio\\'" . bdio-open-file))
+
+(defvar bdio-mode-map
+  (let ((map (make-sparse-keymap)))
+    (keymap-set map "<tab>" #'bdio-toggle-record)
+    map))
+
+(define-derived-mode bdio-mode special-mode "BDIO"
+  "Major mode for viewing BDIO files via lsbdio."
+  (use-local-map bdio-mode-map)
+  (setq buffer-read-only t))
+
+
+(provide 'bdio-mode)