lesson_3_3.py

################################################
# Extend your dictionary program from assignment #2 to have some added capabilities:

# Make sure the user cannot enter more than one translation for the same word, 
# in either direction. For example, if ‘dog’: ‘Hund’ is already an entry in the 
# dictionary, then adding a new translation for ‘dog’ OR another word that translates 
# to ‘Hund’ should fail.

# Make sure the user cannot input a key that contains a space, but a value that 
# contains a space is acceptable. So adding ‘the dog’ : ‘Hund’ should fail, but 
# ‘dog’ : ‘der Hund’ is fine.

if __name__ == '__main__':
    import pickle
    import os

    translations = {}

    if os.path.exists("dict.pickle"):
        try:
            with open('dict.pickle', 'rb') as fin:
                translations = pickle.load(fin)
        except PermissionError:
            print('Unable to open dict.pickle -- Skipping.')

    if translations:
        print(f'Found existing translations: {translations}')

    while (action1 := input("What would you like to do? ")) != "quit":
        if action1 == "help":
            print("Available Actions:\nhelp\nnew\nmod\ndel\nquit")
        elif action1 == "new":
            while (orig := input("Enter a word, or press enter to end: ")) != "":
                if orig in translations:
                    print("A translation already exists for that word!")
                    continue
                if ' ' in orig:
                    print("Words must not contain spaces!")
                    continue

                trans = input("Enter the word's translation: ")
                translations[orig] = trans
        elif action1 == "mod":
            if not translations:
                print("No translations exist yet! Use the 'new' action to create translations!")
                continue

            print(f"Words: {', '.join(translations.keys())}")
            while (orig := input("Enter a word, or press enter to end: ")) != "":
                if orig not in translations:
                    print("That word has not been translated yet!")
                    continue

                trans = input("Enter the word's new translation: ")
                translations[orig] = trans
        elif action1 == "del":
            if not translations:
                print("No translations exist yet!")
                continue

            print(f"Words: {', '.join(translations.keys())}")
            while (orig := input("Enter a word, or press enter to end: ")) != "" and translations:
                if orig not in translations:
                    print("Word does not exist!")
                    continue

                translations.pop(orig)

    print(f"Translations: {translations}")
    store = input("Store translations? (y/n): ")
    if store == 'y':
        try:
            with open("dict.pickle", "wb+") as fout:
                pickle.dump(translations, fout)
        except PermissionError:
            print("Insufficient permissions to store translations!")