"Pijul uses repository-level revision numbering, by hashes."

  "Pijul numbers at the repository-level, by hashes."

;;

(defun vc-pijul--point-status ()
  "Return the status for the current line.
It is assumed that the point is at the beginning of a line, and
the line is the output from \"pijul diff\" for some file."
  (cond
   ((= (point) (point-max)) 'up-to-date)
   ((looking-at-p
     (rx-to-string '(seq bol
                     (or ?A "UD" ?D)
                     (or 32 ?,))
                   t))
    'added)
   ((looking-at-p
     (rx-to-string '(seq bol
                     (or "MV" "U")
                     (or 32 ?,))
                   t))
    'unregistered)
   ((looking-at-p "^D[ ,]") 'removed)
   ((looking-at-p
     (rx-to-string '(seq bol
                     (or "SC" "UC" ?M ?R "RZ")
                     (or 32 ?,))
                   t))
    'edited)))

          (cond
           ((= (point) (point-max)) 'up-to-date)
           ((looking-at-p "^M ") 'edited)
           ((looking-at-p "^MV ") 'added)
           ((looking-at-p "^A ") 'added)
           ((looking-at-p "^D ") 'removed)))))))

          (vc-pijul--point-status))))))

(defun vc-pijul--dir-status-sentinel (hash update-function)
  "Collect the information from the buffer, and update HASH.
Call UPDATE-FUNCTION to notify vc-dir."
  (goto-char (point-min))
  (while (re-search-forward
          (rx-to-string
           '(seq bol
             (one-or-more
              (any (?a . ?z) (?A . ?Z) ?,))
             32
             (group
              (one-or-more not-newline))
             #xa)
           t)
          nil t)
    (forward-line -1)
    (puthash (match-string-no-properties 1)
             (vc-pijul--point-status)
             hash)
    (forward-line 1))
  (let (result)
    (maphash
     (lambda (k v)
       (setq result (cons (list k v) result)))
     hash)
    (funcall update-function result nil)))

  (message "not implemented yet"))

  (let ((default-directory dir)
        (pijul-hash (make-hash-table :test #'equal)))
    (apply #'vc-pijul--async "diff" (current-buffer)
           "--untracked"
           "--short"
           files)
    (vc-run-delayed
      (vc-pijul--dir-status-sentinel pijul-hash update-function))))

  "Return extra backend headers.

  "Return extra backend headers for DIR.

  (let ((args
         (append
          (cond ((integerp limit)
                 (list "--limit" (format "%d" limit))))
          (cons "--" files))))

  (let* ((files (mapcar #'expand-file-name files))
         (files
          (delq
           nil
           (mapcar (lambda (file)
                     (cond
                      ((string=
                        file
                        (expand-file-name (vc-pijul-root file)))
                       nil)
                      (file)))
                   files)))
         (args
          (append
           (cond ((integerp limit)
                  (list "--limit" (format "%d" limit))))
           (cons "--" files))))

        (apply #'vc-do-command
               buffer
               'async
               vc-pijul-program
               nil
               (cons "log" args))))))

        ;; (message "%S" args)
        (apply #'vc-pijul--async "log" buffer args)))))

Return `100' if `vc-pijul-program' is not found on `exec-path'."

Return `100' if `vc-pijul-program' is not found on the variable
`exec-path'."

(defun vc-pijul--async (command buffer &rest arguments)
  "Run pijul with COMMAND and BUFFER asynchronously.
ARGUMENTS are fed to pijul at the end."
  (apply #'vc-do-command
         buffer 'async vc-pijul-program
         nil command arguments))