;;;; Anything that's showed to the user

(defparameter line-sep "===========================")

;;; Menus

(defun show_interface_selection (inter-list)
  "Show interface selection"
  (ext:run-shell-command "netsh interface ipv4 show subinterfaces")
  (let ((selection 1))
    (dolist (inter inter-list)
      (format t "~a - ~a | ~{~a ~}~%" selection (car inter) (cdr inter))
      (setf selection (1+ selection))))
  (format t ">> "))


(defun show_main_menu (&optional preset)
  "Display appropriate menu"
  (format t "
~a
          Main Menu
~a
0 - exit
1 - Show current MTU
2 - Edit MTU
3 - Create Preset MTU~%" line-sep line-sep)
  (when preset
    (format t "4 - Load Preset MTU
5 - Edit Preset MTU
6 - Delete preset MTU~%"))
  (format t "9 - Settings~%>> "))


(defun show_settings_menu ()
  (format t "
~a
       Settings Menu
~a
0 - back
1 - Change Interface~%>> " line-sep line-sep))


(defun edit_mtu ()
    (format t "Selected edit MTU"))


(defun create_preset_mtu ()
    (format t "Selected create preset mtu"))


(defun load_preset_mtu ()
    (format t "Selected load preset MTU"))


(defun edit_preset_mtu ()
    (format t "Selected edit preset MTU"))


(defun delete_preset_mtu ()
    (format t "Selected delete preset MTU"))

All the menu's being displayed

MTU-Changing program - Menus.lisp

Lisp