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##############################################################################
#
# Copyright (c) 2001 Mark Pilgrim and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Convert to and from Roman numerals"""
__author__ = "Mark Pilgrim (f8dy@diveintopython.org)"
__version__ = "1.4"
__date__ = "8 August 2001"
__copyright__ = """Copyright (c) 2001 Mark Pilgrim
This program is part of "Dive Into Python", a free Python tutorial for
experienced programmers. Visit http://diveintopython.org/ for the
latest version.
This program is free software; you can redistribute it and/or modify
it under the terms of the Python 2.1.1 license, available at
http://www.python.org/2.1.1/license.html
"""
import argparse
import re
import sys
# Define exceptions
class RomanError(Exception):
pass
class OutOfRangeError(RomanError):
pass
class NotIntegerError(RomanError):
pass
class InvalidRomanNumeralError(RomanError):
pass
# Define digit mapping
romanNumeralMap = (('M', 1000),
('CM', 900),
('D', 500),
('CD', 400),
('C', 100),
('XC', 90),
('L', 50),
('XL', 40),
('X', 10),
('IX', 9),
('V', 5),
('IV', 4),
('I', 1))
def toRoman(n):
"""convert integer to Roman numeral"""
if not isinstance(n, int):
raise NotIntegerError("decimals can not be converted")
if not (-1 < n < 5000):
raise OutOfRangeError("number out of range (must be 0..4999)")
# special case
if n == 0:
return 'N'
result = ""
for numeral, integer in romanNumeralMap:
while n >= integer:
result += numeral
n -= integer
return result
# Define pattern to detect valid Roman numerals
romanNumeralPattern = re.compile("""
^ # beginning of string
M{0,4} # thousands - 0 to 4 M's
(CM|CD|D?C{0,3}) # hundreds - 900 (CM), 400 (CD), 0-300 (0 to 3 C's),
# or 500-800 (D, followed by 0 to 3 C's)
(XC|XL|L?X{0,3}) # tens - 90 (XC), 40 (XL), 0-30 (0 to 3 X's),
# or 50-80 (L, followed by 0 to 3 X's)
(IX|IV|V?I{0,3}) # ones - 9 (IX), 4 (IV), 0-3 (0 to 3 I's),
# or 5-8 (V, followed by 0 to 3 I's)
$ # end of string
""", re.VERBOSE)
def fromRoman(s):
"""convert Roman numeral to integer"""
if not s:
raise InvalidRomanNumeralError('Input can not be blank')
# special case
if s == 'N':
return 0
if not romanNumeralPattern.search(s):
raise InvalidRomanNumeralError('Invalid Roman numeral: %s' % s)
result = 0
index = 0
for numeral, integer in romanNumeralMap:
while s[index:index + len(numeral)] == numeral:
result += integer
index += len(numeral)
return result
def parse_args():
parser = argparse.ArgumentParser(
prog='roman',
description='convert between roman and arabic numerals'
)
parser.add_argument('number', help='the value to convert')
parser.add_argument(
'-r', '--reverse',
action='store_true',
default=False,
help='convert roman to numeral (case insensitive) [default: False]')
args = parser.parse_args()
args.number = args.number
return args
def main():
args = parse_args()
if args.reverse:
u = args.number.upper()
r = fromRoman(u)
print(r)
else:
i = int(args.number)
n = toRoman(i)
print(n)
return 0
if __name__ == "__main__": # pragma: no cover
sys.exit(main()) # pragma: no cover
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