teach emacs to use wl-copy

wl-clipboard.el

  (setq wl-copy-process nil)
  (defun wl-copy (text)
    (setq wl-copy-process (make-process :name "wl-copy"
                                        :buffer nil
                                        :command '("wl-copy" "-f" "-n")
                                        :connection-type 'pipe))
    (process-send-string wl-copy-process text)
    (process-send-eof wl-copy-process))
  (defun wl-paste ()
    (if (and wl-copy-process (process-live-p wl-copy-process))
        nil ; should return nil if we're the current paste owner
        (shell-command-to-string "wl-paste -n | tr -d \r")))
  (setq interprogram-cut-function 'wl-copy)
  (setq interprogram-paste-function 'wl-paste)

@yorickvP You still need this when running Emacs in a terminal.

I improved the snippet a bit to limit the use of wl-copy and wl-paste to Emacs running in terminal only:

   ;; Set up wl-copy and wl-paste in terminal Emacs
  (when (and (string= (getenv "XDG_SESSION_TYPE") "wayland")
             (executable-find "wl-copy")
             (executable-find "wl-paste"))
    (defun my-wl-copy (text)
      "Copy with wl-copy if in terminal, otherwise use the original value of `interprogram-cut-function'."
      (if (display-graphic-p)
          (gui-select-text text)
        (let ((wl-copy-process
               (make-process :name "wl-copy"
                             :buffer nil
                             :command '("wl-copy")
                             :connection-type 'pipe)))
          (process-send-string wl-copy-process text)
          (process-send-eof wl-copy-process))))
    (defun my-wl-paste ()
      "Paste with wl-paste if in terminal, otherwise use the original value of `interprogram-paste-function'."
      (if (display-graphic-p)
          (gui-selection-value)
        (shell-command-to-string "wl-paste --no-newline")))
    (setq interprogram-cut-function #'my-wl-copy)
    (setq interprogram-paste-function #'my-wl-paste))