;;; my-ielm-history.el -- to save ielm history using a hook.  (posted,
;;; madhu 20241013)

;; comint-input-ring-separator and ielm-write-input-wring taken from
;; sly

(defun my-ielm-read-input-ring ()
  (let ((comint-input-ring-separator "####\n"))
    (comint-read-input-ring)))

(defun my-ielm-process-sentinel (proc msg)
  (let ((buffer (process-buffer (get-process proc))))
    (when (buffer-live-p buffer)
      (with-current-buffer buffer
	(my-ielm-write-input-ring))))
  (internal-default-process-sentinel proc msg))

(defun my-ielm-write-input-ring ()
  ;; not enough to make it buffer-local. The binding has to exist when
  ;; the rings is being written to " *Temp Input History*"
  (let* ((comint-input-ring-separator "####\n")
	 ;; To merge the file's history with the current buffer's
	 ;; history, sntart by deep-copying `comint-input-ring' to a
	 ;; separate variable.
	 (current-ring (copy-tree comint-input-ring 'vectors-too))
	 (histcontrol 'erasedups)
	 (index (ring-length current-ring))
	 )
    ;; this sets `comint-input-ring' from the file
    (my-ielm-read-input-ring)
    ;; loop `current-ring', which potentially contains new entries and
    ;; re-add entries to `comint-input-ring', which is now synched
    ;; with the file and will be written to disk.
    (cl-loop for i from (1- index) downto 0
             for item = (ring-ref current-ring i)
             for existing-index = (ring-member comint-input-ring item)
             do (cond ((and existing-index
                            (eq histcontrol 'erasedups))
                       (ring-remove comint-input-ring existing-index)
                       (ring-insert comint-input-ring item))
                      ((and existing-index
                            (not histcontrol))
                       (ring-insert comint-input-ring item))
                      (t
                       (ring-insert comint-input-ring item)))
             unless (ring-member comint-input-ring item)
             do (ring-insert comint-input-ring item))
    ;; Now save `comint-input-ring'
    (let ((coding-system-for-write 'utf-8-unix))
      (comint-write-input-ring))))

;; madhu 060520
(add-hook 'ielm-mode-hook
	  (defun my-ielm-mode-hook ()
	    (set-process-sentinel (get-buffer-process (current-buffer))
				  'my-ielm-process-sentinel)
	    ;;(make-variable-buffer-local 'comint-input-ring-separator)
	    (setq comint-input-ignoredups t
		  comint-input-ring-file-name
		  ;;comint-input-ring-separator "####\n" ;madhu 200131
		  (expand-file-name "~/.ielm-history.el")
		  comint-input-ring-size 1000)
	    ;;(make-local-hook 'kill-buffer-hook)
	    (add-hook 'kill-buffer-hook 'my-ielm-write-input-ring nil t)))

(defun fix-ielm-buffer ()
  "put #### markers between sexps in a ielm history buffer without those"
  (while (not (eobp))
    (forward-sexp)
    (assert (eolp))
    (cond((eolp)
	  (insert "####")
	  (forward-line 1))
	 (t (debug)))))