Dynamic user-created menus with sub-menus in a command line script

Question

Questions:

• How could this code be written better?
• Could this be written in less lines of code if constructed using classes?
• Also, If the user-created menu items were to be saved to a file for later use, which would be the best approach to use? (pickle? plain text file? etc.)

Problems:

• How do I dynamically draw the fixed menu items in the settings menu from a list or dict?
• How to make items selectable by number or a specific character?
• My main struggle came with dynamically displaying and executing sub-menu items.

---

Preface:

After about 3 weeks of research, trial and error, playing with different approaches and data structures, I ended up scrapping all my code and resigning myself to writing the following code.

This problem originated as a programming that challenged I created for myself and it now haunts me because I am having to admit defeat by asking you guys for guidance. This drives me crazy since I know there are probably very elegant ways of writing this script, but this was the only way I could make it work and produce the desired outputs.

I have spent hours researching stackoverflow and other sites for similar answers, but none fully addressed my particular design goals, such as dealing with sub-menus and the dynamic nature of this menu system.

I should also mention that I have not fully coded every aspect of this script, but there is enough here to allow the creation of menu items and demonstrate what i'm trying to achieve.

---

#!/usr/bin/python
import sys, os

menu_actions = {}
user_menu_items = []


def add_userItem(item):
  returnitem = "item " + item + " created..."
  return returnitem

def show_settings():
  os.system('clear')

  print "\nEdit"
  print "Default Settings"
  print "\nBack"
  choice = raw_input(" >>  ")
  if choice.lower() == 'back':
    main_menu()
  else:
    decision(choice)
  return

def quit():
  raise SystemExit()

def s_edit():
  os.system('clear')
  print "\nCreate"
  print "Modify"
  print "\nBack\n"
  choice = raw_input(" >>  ")
  if choice.lower() == 'back':
    show_settings()
  else:
    decision(choice)
  return

def s_default():
  os.system('clear')
  choice = raw_input("(**All user created menus will be erased**)\nAre you sure? (YES / NO)  or Back\n >>  ")
  if choice.lower() == 'back':
    show_settings()
  elif choice.lower() == 'yes':
    print 'all settings have been set to default'
    del user_menu_items[:]  # removing all items from user menu
    show_settings()
  elif choice.lower() == 'no':
    show_settings()
  return

def e_create():
  go = True
  addeditem = []
  global user_menu_items
  while go:      
    badinput = False
    if badinput == True:
      print "That's not a selection. Please try again..."
    else:
      os.system('clear')
      if addeditem != '':
        z = 0
        for i in addeditem:
          print(addeditem[z])
          z += 1
      if not user_menu_items:
        print
      print "\n**Menu Items**"
      z = 0
      for i in user_menu_items:
        print(user_menu_items[z])
        z += 1
      choice = raw_input("\nCreate New Item? (YES / NO)\n >>  ")
    if choice.lower() == 'yes':
      additem = raw_input("\n\nSpecify Name of New Menu Item: ")
      addeditem.append(add_userItem(additem))
      user_menu_items.append(additem)
    else:
      if choice.lower() == 'no':
    go = False
      else: 
    badinput = True
  s_edit()
  return

def e_modify():
  os.system('clear')
  print "Rename"
  print "Delete"
  print "Move Item"
  print "\nBack\n"
  choice = raw_input("Choose an action: ")
  return choice

def m_rename():
  os.system('clear')
  print "\nBack\n"
  choice = raw_input("Enter a new name: ")
  return choice

def m_delete():
  os.system('clear')
  print "\nBack\n"
  choice = raw_input("Select Menu Item to Delete: ")
  return choice

def m_move():
  os.system('clear')
  print "\nBack\n"
  choice = raw_input("Specify new location: ")
  return choice

def goback():
  os.system('clear')
  print "\nBack\n"
  decision('')
  return

def user_menu():
  z = 0
  for i in user_menu_items:
    print(user_menu_items[z])
    z += 1
  return

def main_menu():
  os.system('clear')
  user_menu()
  print "\nSettings"
  print "Quit"
  choice = raw_input(" >>  ")
  decision(choice)
  return

def decision(decision):
  dec = decision.lower()
  if dec == '':
    menu_actions['main menu']()
  else:  
    try:
      menu_actions[dec]()
    except KeyError:
      print "invalid selection, please try again.\n"
      menu_actions['main menu']()
  return

menu_actions = {
  'main': main_menu,
  'settings': show_settings,
  'quit': quit,
  'edit': s_edit,
  'default': s_default,
  'create': e_create,
  'modify': e_modify,
  'rename': m_rename,
  'delete': m_delete,
  'move': m_move,
  'back' : goback
  }

main_menu()

About: As you can see, I have designed a menu creator based on user input, while still providing a fixed menu system for creating and modifying the user-created menus. My desire was to display one tier at a time, making menu items numerically selectable (except for "go back" and "quit"). Below is a pseudo code view of my desired menu tree.

I should also mention that I am fully aware of the fact that the user-created menu items will not have any particular functionality, but I figured I could use this program to create the menus and then code functionality later on -- if desired.

Desired Menu Tree:

1. Settings

   1. Edit Menu

      1. Create > # Specify Location of Menu Item. > # Specify Name of New Menu Item.
      2. Modify > # Select Menu Item to Modify. > # Pick an Action?
         1. Rename > # Enter a new name
         2. Delete > # Select Menu Item to Delete.
         3. Move Item > # Where?

      x. Go Back

   2. Default Settings (All user created menus will be erased) > #Are you sure? (YES / NO?)

x. Quit > #exit program

Answer 1

Disclaimer : your code is not indented properly and I cannot run it. Also, it seems a bit convoluted to me so I haven't really tried to understand it. However, here are a few comments that might help you if you want to improve your code.

---

Keep it simple

def add_userItem(item):
  returnitem = "item " + item + " created..."
  return returnitem

could be

def add_userItem(item):
  return "item " + item + " created..."

---

goback could just call main_menu() instead of decision(''). This would make decision() much simpler as it shouldn't be its duty to try to handle special cases (see Separation of Concerns)

---

You don't need to have menu_actions at the top of your file.

---

return at the end of the function is not required if you don't plan to return any value.

---

  choice = raw_input("Choose an action: ")
  return choice

could be

  return raw_input("Choose an action: ")

---

---

For Loop

The way Python loops is designed is supposed to help you to write concise and expressive code : what you write should match pretty closely how you think about things : "I want to do this for each item in this container" instead of "I want to have this index and I start at 0 and I increment and I get the element at this index...".

    z = 0
    for i in addeditem:
      print(addeditem[z])
      z += 1

should be written :

    for i in addeditem:
      print(i)

How nice is this ?

Pretty much everytime you initialise a variable at 0 to use it as an index in a loop you are doing it wrong. If you really need to know what is the current index, enumerate is what you are looking for.

---

---

Don't repeat yourself

  for i in user_menu_items:
    print(i)

appears in your code twice. You should just call user_menu.

---

Multiple methods looks quite similar, it might be worth defining a more generic function and then just calling it everywhere

---

  if choice.lower() == 'back':
    show_settings()
  elif choice.lower() == 'yes':
    print 'all settings have been set to default'
    del user_menu_items[:]  # removing all items from user menu
    show_settings()
  elif choice.lower() == 'no':
    show_settings()

calls lower() and show_settings in 3 different places. It might be easier to do something like :

  choice = raw_input("(**All user created menus will be erased**)\nAre you sure? (YES / NO)  or Back\n >>  ").lower()
  if choice == 'yes':
    print 'all settings have been set to default'
    del user_menu_items[:]  # removing all items from user menu
    show_settings()
  elif choice in ['back','no']:
    show_settings()

---

If you ever change the label of menu (which most likely happened already - I assume that main menu is its old name), things will fail and you'll have to fix it in different places in decision.

What about doing :

def decision(decision):
    try:
      menu_actions[decision.lower()]()
    except KeyError:
      print "invalid selection, please try again.\n"
      main_menu()

---

Documentation

You should add comments at least to describe the program and the different main functions.