morder.py

def morse_encryptor(message_text):
    """
    This functions encrypts a English text into corresponding
    morse-code equivalent (i.e. cipher text) and returns the same
    """

    # Convert the message-text to all uppercases for easy lookup in the dictionary
    message_text = message_text.upper()

    # Initialise cipher-text
    encrypted_text = ""

    for letter in message_text:

        # If there is a space in message-text, add one to cipher-text too
        if letter == ' ':
            encrypted_text += letter

        # Else, find the equivalent encrypted letter to English letter and
        # append that to the end of encrypted text
        else:
            encrypted_text += morse_codes[letter] + " "

    return encrypted_text


def morse_decryptor(encrypted_text):
    """
    This function decrypts the encrypted-text (i.e. cipher text) and
    return a English text
    """

    # To mark end of last character
    encrypted_text += ' '

    # message_text : Final English sentence obtained on decrypting cipher text
    message_text = ""

    # Consecutive characters in morse are separated by spaces, this contains last charaacter
    char_in_morse = ""

    # Depending on if there are 1 or 2 consecutive spaces, words and letters will
    # be initiated (Letters have single while words have double spaces in between)
    consecutive_spaces = 0

    for morse_character in encrypted_text:

        # Check if this is end of a word of letter
        if morse_character == ' ':

            # Increament number of consecutive spaces encountered so far
            consecutive_spaces += 1

            # If there is single space between two morse-letters, it means that this is
            # end of one of the morse-letter
            if consecutive_spaces == 1:

                # Accessing keys using values in dictionary - Use the dictionary as lists
                message_text += morse_codes.keys(
                    )[morse_codes.values().index(char_in_morse)]

                # Reinitialise the word in morse
                char_in_morse = ""

            # If there are two spaces, it means it is end of a morse-word
            else:
                message_text += " "
                consecutive_spaces = 0

        # Otherwise, add the decrypted morse-letter to the message-text
        else:
            consecutive_spaces = 0
            char_in_morse += morse_character

    return message_text


# A dictionary storing the morse-code equivalents for most letters, numbers, symbols in English
morse_codes = {
        'A': ".-", 'B': "-...", 'C': "-.-.", 'D': "-..", 'E': ".",
        'F': "..-.", 'G': "--.", 'H': "....", 'I': "..", 'J': ".---",
        'K': "-.-", 'L': ".-..", 'M': "--", 'N': "-.", 'O': "---",
        'P': ".--.", 'Q': "--.-", 'R': ".-.", 'S': "...", 'T': "-",
        'U': "..-,", 'V': "...-", 'W': ".--", 'X': "-..-", 'Y': "-.--",
        'Z': "--..", '.': ".-.-.-", ',': "--..--", '?': "..--..",
        '/': "-..-.", '@': ".--.-.", '(': "-.--.", ')': "-.--.-",
        '-': "-....-", '1': ".----", '2': "..---", '3': "...--",
        '4': "....-", '5': ".....", '6': "-....", '7': "--...",
        '8': "---..", '9': "----.", '0': "-----"
        }