Add roman numeral library

lib/tvnamer/roman.py

+## {{{ http://code.activestate.com/recipes/81611/ (r2)
+def int_to_roman(input):
+   """
+   Convert an integer to Roman numerals.
+
+   Examples:
+   >>> int_to_roman(0)
+   Traceback (most recent call last):
+   ValueError: Argument must be between 1 and 3999
+
+   >>> int_to_roman(-1)
+   Traceback (most recent call last):
+   ValueError: Argument must be between 1 and 3999
+
+   >>> int_to_roman(1.5)
+   Traceback (most recent call last):
+   TypeError: expected integer, got <type 'float'>
+
+   >>> for i in range(1, 21): print int_to_roman(i)
+   ...
+   I
+   II
+   III
+   IV
+   V
+   VI
+   VII
+   VIII
+   IX
+   X
+   XI
+   XII
+   XIII
+   XIV
+   XV
+   XVI
+   XVII
+   XVIII
+   XIX
+   XX
+   >>> print int_to_roman(2000)
+   MM
+   >>> print int_to_roman(1999)
+   MCMXCIX
+   """
+   if type(input) != type(1):
+      raise TypeError, "expected integer, got %s" % type(input)
+   if not 0 < input < 4000:
+      raise ValueError, "Argument must be between 1 and 3999"   
+   ints = (1000, 900,  500, 400, 100,  90, 50,  40, 10,  9,   5,  4,   1)
+   nums = ('M',  'CM', 'D', 'CD','C', 'XC','L','XL','X','IX','V','IV','I')
+   result = ""
+   for i in range(len(ints)):
+      count = int(input / ints[i])
+      result += nums[i] * count
+      input -= ints[i] * count
+   return result
+
+
+
+def roman_to_int(input):
+   """
+   Convert a roman numeral to an integer.
+   
+   >>> r = range(1, 4000)
+   >>> nums = [int_to_roman(i) for i in r]
+   >>> ints = [roman_to_int(n) for n in nums]
+   >>> print r == ints
+   1
+
+   >>> roman_to_int('VVVIV')
+   Traceback (most recent call last):
+    ...
+   ValueError: input is not a valid roman numeral: VVVIV
+   >>> roman_to_int(1)
+   Traceback (most recent call last):
+    ...
+   TypeError: expected string, got <type 'int'>
+   >>> roman_to_int('a')
+   Traceback (most recent call last):
+    ...
+   ValueError: input is not a valid roman numeral: A
+   >>> roman_to_int('IL')
+   Traceback (most recent call last):
+    ...
+   ValueError: input is not a valid roman numeral: IL
+   """
+   if type(input) != type(""):
+      raise TypeError, "expected string, got %s" % type(input)
+   input = input.upper()
+   nums = ['M', 'D', 'C', 'L', 'X', 'V', 'I']
+   ints = [1000, 500, 100, 50,  10,  5,   1]
+   places = []
+   for c in input:
+      if not c in nums:
+         raise ValueError, "input is not a valid roman numeral: %s" % input
+   for i in range(len(input)):
+      c = input[i]
+      value = ints[nums.index(c)]
+      # If the next place holds a larger number, this value is negative.
+      try:
+         nextvalue = ints[nums.index(input[i +1])]
+         if nextvalue > value:
+            value *= -1
+      except IndexError:
+         # there is no next place.
+         pass
+      places.append(value)
+   sum = 0
+   for n in places: sum += n
+   # Easiest test for validity...
+   if int_to_roman(sum) == input:
+      return sum
+   else:
+      raise ValueError, 'input is not a valid roman numeral: %s' % input
+## end of http://code.activestate.com/recipes/81611/ }}}