;;; xsel --- use X clipboard to/from terminal/tty Emacs

;;; Commentary:
;;
;; This file: http://user.it.uu.se/~embe8573/conf/emacs-init/xsel.el
;;
;;     .-----------------------------------------.
;;     |  xsel - faster, keyboard-only,          |
;;     |         more intuitive X clipboard,     |
;;     |         from a Linux VT/console/tty     |
;;     |         or X terminal emulator          |
;;     |   by Emanuel Berg                       |
;;     |   embe8573 AT&T student DOS uu DOS se   |
;;     |   first created: way back in 2013-14?   |
;;     |   updated: 05:43, 13/05/2015            |
;;     '-----------------------------------------'
;;
;; This gives you to gain access to the X clipboard
;; from a terminal, or a Linux VT/console/tty Emacs
;; instance. (In X: faster keyboard access,
;; I suppose.)
;;
;; Possible: Insert the X clipboard at point and
;; forward point accordingly.
;;
;; DWIM: If there is a region, replace it with the
;; X clipboard.
;;
;; Also possible: set the X clipboard programmatically
;; in Elisp or set it interactively to the current
;; region (if there is one), otherwise set it to the
;; most recent Emacs kill (without popping the kill
;; ring).
;;
;; If DISPLAY is set, it is used; otherwise, use ":0".

;;; Code:

(defvar xsel-X-display (or (getenv "DISPLAY") ":0"))

(defun insert-X-clipboard ()
  "Insert the X clipboard at point using the X tool xsel.
For it to work, X needs to run.
After that, move point to the end of the inserted clipboard.
If there is a region at the time of invocation,
first delete the region
- i.e., replace it with the X clipboard.
See `set-X-clipboard-to-string'."
  (interactive)
  (if mark-active (delete-region (mark) (point)))
  (shell-command
   (format "xsel --display \"%s\" -b -o" xsel-X-display) 1)
  (goto-char (mark)) )

(defun set-X-clipboard-to-string (s)
  "Set the X clipboard to S.
See `set-X-clipboard' and `insert-X-clipboard' for details."
  (shell-command
   (format "echo -n %s | xsel --display %s -b -i" s xsel-X-display) ))

(defun set-X-clipboard ()
  "If there is a region, set the X clipboard to the contents of that region.
If there isn't a region,
set the X clipboard to the most recent Emacs kill,
without popping it from the kill ring.
See `insert-X-clipboard'."
  (interactive)
  (let ((input (if mark-active (buffer-substring-no-properties (mark) (point))
                 (string-make-unibyte (current-kill 0 t)) )))
    (set-X-clipboard-to-string (shell-quote-argument input)) ))

;; This   package  can   be  used   to  get   complete
;; transparency  - but  it is  probably over"kill"  to
;; have it enabled for every single kill.
;;
;; (setq interprogram-cut-function ...)

;; misc shorthands:

(defun x-copy-buffer ()
  "Copy the buffer's contents to the X clipboard."
  (interactive)
  (save-excursion
    (mark-whole-buffer)
    (set-X-clipboard)
    (keyboard-quit) ))

(defalias 'xb 'x-copy-buffer)

(defalias 'pst  'insert-X-clipboard)
(defalias 'xo   'insert-X-clipboard)

(defalias 'cpy' 'set-X-clipboard)
(defalias 'xi   'set-X-clipboard)

(provide 'xsel)

;;; xsel.el ends here