In my side quest to find a concise and fun way to create menus, I have now created minimalmenu3.py

minimalmenu3.py

#!/usr/bin/env python3

"""
minimalmenu3.py by @TimelessP.
MIT Licence.
2022-08-04
https://gist.github.com/TimelessP/8d45006bab00ec634a474bf3453f1772
"""
import os
import subprocess
from enum import Enum


class Actions(Enum):
    FUNCTION = 1
    EXIT = 2
    MENU = 3
    SHELL_COMMAND = 4


class Menu:
    def __init__(self, menu_data):
        self.menu_data = menu_data
        self._choice = None
        self._menu_title = None

    def run(self):
        while True:
            self._print_menu()
            self._get_input()
            if self._choice and self._choice.get(Actions.EXIT, None):
                # If it's callable, call it first, then break out the loop.
                if callable(self._choice[Actions.EXIT]):
                    self._choice[Actions.EXIT]()

                break

            self._process_input()

    def _print_menu(self):
        # Print the current menu.
        self._menu_title = list(self.menu_data.keys())[0]
        print(os.linesep + self._menu_title + os.linesep + "-" * len(self._menu_title))
        # Print the menu items.
        for index, option in enumerate(self.menu_data[self._menu_title], start=1):
            print(f"{index}. {option['option']}")

    def _get_input(self):
        try:
            self._choice = None
            # The user inputs the choice number, and we store the selected option in self.choice.
            choice_number = input("? ")
            # Validate the choice.
            if choice_number.isdigit():
                choice_number = int(choice_number)
                if choice_number in range(1, len(self.menu_data[self._menu_title]) + 1):
                    # Store the selected option as the choice.
                    self._choice = self.menu_data[self._menu_title][choice_number - 1]
                else:
                    print("Invalid choice.")
                    self._choice = None
            else:
                print("Invalid choice.")
        except (KeyboardInterrupt, EOFError):
            return

    def _process_input(self):
        # Process the input.
        if self._choice:
            if self._choice.get(Actions.FUNCTION, None):
                # Call the function.
                self._choice[Actions.FUNCTION]()
            elif self._choice.get(Actions.MENU, None):
                # Change the current menu.
                next_menu = self._choice.get(Actions.MENU)
                # If next_menu is a str then eval() the string.
                if isinstance(next_menu, str):
                    next_menu = eval(next_menu)

                self.menu_data = next_menu
            elif self._choice.get(Actions.SHELL_COMMAND, None):
                # Run a shell command and print the return code.
                print(f"Return code: {subprocess.call(self._choice[Actions.SHELL_COMMAND], shell=True)}")

            self._choice = None


def print_hello():
    print("Hello World")


def print_goodbye():
    print("Goodbye World")
    exit(0)


if __name__ == '__main__':
    sub_menu = {
        "Sub Menu": [
            {"option": "Print hello", Actions.FUNCTION: print_hello},
            {"option": "Main Menu", Actions.MENU: 'main_menu'},
        ]
    }

    main_menu = {
        "Main Menu": [
            {"option": "Print hello", Actions.FUNCTION: print_hello},
            {"option": "Sub menu", Actions.MENU: sub_menu},
            {"option": "Lambda test", Actions.FUNCTION: lambda: print("Lambda test")},
            {"option": "Directory listing", Actions.SHELL_COMMAND: "ls || dir"},
            {"option": "Exit", Actions.EXIT: print_goodbye},
        ]
    }

    Menu(main_menu).run()