Numerica - Practice Japanese numbers with the help of a computer!

numerica.py

#!/usr/bin/env python3

"""
This is a program to help you study the Japanese numbers.
It currently goes from 0 to 99; I will extend it at a later date.

It can be executed as follows:

    ./numerica.py

which will do all the available numbers, or

    ./numberica.py 10

which will go only up to 10.
"""

numbers = ['ZERO',
           'いち',
           'に',
           'さん',
           'よん',
           'ご',
           'ろく',
           'なな',
           'はち',
           'きゅう',
           'じゅう',
           ]


class OutOfRangeException(Exception):
    pass


def small_to_japanese(n):
    "Convert a number (0-10) to Japanese."
    if n > 10 or n < 0:
        raise OutOfRangeException

    return numbers[n]


def medium_to_japanese(n):
    "Convert a number from 11 - 100 to Japanese"
    if n > 100 or n < 11:
        raise OutOfRangeException

    digits = list(map(
        int, str(n)
    ))

    out = ""

    # Omit いち in numbers > 10
    if digits[0] > 1:
        out += numbers[digits[0]] + " "
    out += numbers[10] + " "
    out += numbers[digits[1]]
    return out


def number_to_japanese(n):
    try:
        return small_to_japanese(n)
    except OutOfRangeException:
        pass

    try:
        return medium_to_japanese(n)
    except OutOfRangeException:
        pass

    print("No way to represent numbers of that magnitude!")


if __name__ == "__main__":
    from random import randint
    from sys import argv

    # Check if there is a command line option for max numbers
    if len(argv) >= 2:
        try:
            MAX_NUM = int(argv[1])
        except ValueError:
            MAX_NUM = -1

        # A little edge case handling
        if MAX_NUM > 99:
            print("Impossible - this program doesn't "
                  "work with numbers over 99.")
            exit(1)

    else:
        # If a max wasn't given, default to 99
        MAX_NUM = 99

    given = ""
    done_so_far = []
    number_done = 0

    while True:
        n = randint(0, MAX_NUM)
        # If and as long as n has already been done, get a new number.
        while n in done_so_far:
            n = randint(0, MAX_NUM)

        try:
            given = input("What is {} in Roman numbers? ".format(
                number_to_japanese(n)))
        except KeyboardInterrupt:
            print("Bye!")
            exit(1)
        except EOFError:
            print("Bye!")
            exit(1)

        if given.lower() == 'quit':
            print("Bye!")
            exit(0)
        if number_done >= MAX_NUM:
            print("You did all the numbers in that set!")
            exit(0)

        try:
            given_n = int(given)
        except ValueError:
            given_n = -1

        if given_n == n:
            print("You got it!")
            done_so_far.append(n)
            number_done += 1
        else:
            print("No, that's incorrect. This is {}.".format(n))