Multiple browsers in emacs

[aalinovi@riseup.net]

This is with emacs-29.2 on OpenBSD -current.

Not knowing lisp, I simply copied the following from:

https://noonker.github.io/posts/2020-04-22-elfeed/:

(defun elfeed-eww-open (&optional use-generic-p)
  "open with eww"
  (interactive "P")
  (let ((entries (elfeed-search-selected)))
    (cl-loop for entry in entries
             do (elfeed-untag entry 'unread)
             when (elfeed-entry-link entry)
             do (eww-browse-url it))
    (mapc #'elfeed-search-update-entry entries)
    (unless (use-region-p) (forward-line))))

(defun elfeed-firefox-open (&optional use-generic-p)
  "open with firefox"
  (interactive "P")
  (let ((entries (elfeed-search-selected)))
    (cl-loop for entry in entries
             do (elfeed-untag entry 'unread)
             when (elfeed-entry-link entry)
             do (browse-url-firefox it))
    (mapc #'elfeed-search-update-entry entries)
    (unless (use-region-p) (forward-line))))

(defun elfeed-w3m-open (&optional use-generic-p)
  "open with w3m"
  (interactive "P")
  (let ((entries (elfeed-search-selected)))
    (cl-loop for entry in entries
             do (elfeed-untag entry 'unread)
             when (elfeed-entry-link entry)
             do (ffap-w3m-other-window it))
    (mapc #'elfeed-search-update-entry entries)
    (unless (use-region-p) (forward-line))))

(define-key elfeed-search-mode-map (kbd "t") 'elfeed-w3m-open)
(define-key elfeed-search-mode-map (kbd "w") 'elfeed-eww-open)
(define-key elfeed-search-mode-map (kbd "f") 'elfeed-firefox-open)

Everything works fine except for "t" elfeed-w3m-open which results in
 "Symbol's function definition is void: ffap-w3m-other-window"

I was unfamiliar with ffap so I tried enabling it. It seems to have made no difference.

Any assistance would be appreciated.

Thank you

Arthur