latinicabot/latinica.py

import sys

RULES = [
  (('т', 'ь', 'с', 'я'), 't\u0341sá'),
  (('т', 'ь', 'с', 'ю'), 't\u0341sú'),
  (('т', 'с', 'я'), 'tsá'), 
  (('т', 'с', 'ю'), 'tsú'),

  (('ы', 'й', 'B'), ('ý', -3)),
  (('ч', 'ь', 'B'), (-1, -3)),
  (('ш', 'ь', 'B'), (-1, -3)),
  (('л', 'ь', 'B'), ('lj', -3)),

  (('л', 'я', 'я'), (-1, -2, 'á')),
  (('л', 'ю', 'ю'), (-1, -2, 'ú')),
  (('л', 'я', 'ю'), (-1, -2, 'ú')),
  (('л', 'ю', 'я'), (-1, -2, 'á')),

  (('н', 'я', 'я'), (-1, -2, 'á')),
  (('н', 'ю', 'ю'), (-1, -2, 'ú')),
  (('н', 'я', 'ю'), (-1, -2, 'ú')),
  (('н', 'ю', 'я'), (-1, -2, 'á')),

  (('S', 'е'), (-1, '\u0341')),
  (('B', 'е'), (-1, -2, '\u0341')),

  (('я', 'я'), (-1, 'á')),
  (('ю', 'ю'), (-1, 'ú')),
  (('я', 'ю'), (-1, 'ú')),
  (('ю', 'я'), (-1, 'á')),

  (('д', 'ж'), 'đ'),
  #(('к', 'с'), 'x'),
  (('ч', 'ь'), (-1, -2)),
  (('ш', 'ь'), (-1, -2)),
  (('щ', 'ь'), (-1, -2)),
  (('C', 'ь'), (-1, '\u0341')),

  (('л', 'ё'), (-1, -2)),

  (('н', 'я'), (-1, -2)),
  (('л', 'я'), (-1, -2)),
  (('ш', 'я'), (-1, -2)),
  (('щ', 'я'), (-1, -2)),
  (('ж', 'я'), (-1, -2)),
  (('^C', '^я'), (-1, 'ja')),
  (('C', 'я'), (-1, 'ía')),

  (('н', 'ю'), (-1, -2)),
  (('л', 'ю'), (-1, -2)),
  (('ш', 'ю'), (-1, -2)),
  (('щ', 'ю'), (-1, -2)),
  (('ж', 'ю'), (-1, -2)),
  (('^C', '^ю'), (-1, 'ju')),
  (('C', 'ю'), (-1, 'íu')),

  (('н', 'ё'), (-1, -2)),
  (('л', 'ё'), (-1, -2)),
  (('ш', 'ё'), (-1, -2)),
  (('щ', 'ё'), (-1, -2)),
  (('ж', 'ё'), (-1, -2)),
  (('^C', '^ё'), (-1, 'jo')),
  (('C', 'ё'), (-1, 'ío')),

  (('V', 'е'), (-1, -2, '\u0341')),

  (('а',), 'a'),
  (('б',), 'b'),
  (('в',), 'v'),
  (('г',), 'g'),
  (('д',), 'd'),
  (('е',), 'e'),
  (('^ё',), ('jo',)),
  (('ё',), 'jo'),
  (('ж',), 'ž'),
  (('з',), 'z'),
  (('и',), 'i'),
  (('й',), 'j'),
  (('к',), 'k'),
  (('л',), 'l'),
  (('м',), 'm'),
  (('н',), 'n'),
  (('о',), 'o'),
  (('п',), 'p'),
  (('р',), 'r'),
  (('с',), 's'),
  (('т',), 't'),
  (('у',), 'u'),
  (('ф',), 'f'),
  (('х',), 'h'),
  (('ц',), 'c'),
  (('ч',), 'č'),
  (('ш',), 'š'),
  (('щ',), 'ŝ'),
  (('ъ',), '\''),
  (('ы',), 'y'),
  (('ь',), '\''),
  (('э',), 'ě'),
  (('^ю',), ('ju',)),
  (('^я',), ('ja',)),
  (('ю',), 'ju'),
  (('я',), 'ja'),

  ('*', (0,))
]

VOWELS = 'аеёийоуыэюя'
CONSONANTS = 'бвгджзклмнпрстфхцчшщьъ'

def is_vowel(letter):
  return letter in VOWELS

def is_consonant(letter):
  return letter in CONSONANTS

def is_word_boundary(letter):
  return letter in (None, ' ', '.', ',', '!', '?', ':', ';', '/', '&', ')', ']', '}', '\n', '\t')

class Converter:
  def __init__(self, source):
    self._source = source
    self._output = ''

    self._position = 0
    self._start_position = 0

    self._matched_letters = []

  def _look(self, n=0, lower=True):
    position = self._position + n

    if position >= len(self._source)\
    or position < 0:
      return None

    return self._source[position].lower() if lower else self._source[position]

  def _match_letter(self, letter, n=0):
    letter_ahead = self._look(n)

    self._matched_letters.append(letter_ahead)

    if not letter_ahead or not letter:
      return letter is letter_ahead

    if letter[0] == '^':
      letter = letter[1]

      self._matched_letters.pop()

      return self._match_letter(letter, n) and self._look(n, lower=False).isupper()
        
    if letter == '*':
      return True

    if letter == 'V' and is_vowel(letter_ahead):
      return True
    elif letter == 'C' and is_consonant(letter_ahead):
      return True
    elif letter == 'B' and is_word_boundary(letter_ahead):
      return True

    if letter == letter_ahead:
      return True

    return False

  def _match(self, pattern):
    self._matched_letters = []

    if pattern[0] == 'S':
      if self._position != 0:
        return False

      pattern = pattern[1:]

    for n in range(len(pattern)):
      if not self._match_letter(pattern[n], n):
        return False

    self._start_position = self._position
    self._position += len(pattern)

    return True

  def _convert_letter(self, letter):
    if not letter:
      return ''

    for pattern, replacement in RULES:
      if len(pattern) == 1\
     and pattern[0] == letter:
        return replacement

    return letter

  def _is_upper(self, n=0):
    position = self._start_position + n

    if position >= len(self._source)\
    or position < 0:
      return False

    return self._source[position].isupper()

  def _insert(self, letters):
    buffer = ''

    for letter, n in zip(letters, range(len(letters))):
      if type(letter) is int:
        if letter < 0:
          letter = self._convert_letter(self._matched_letters[abs(letter) - 1])
        else:
          letter = self._matched_letters[letter]
     
      buffer += (letter.capitalize() if letter[0] == 'j' else letter.upper()) if self._is_upper(n) else letter

    self._output += buffer

  def convert(self):
    while True:
      for pattern, replacement in RULES:
        if self._match(pattern): 
          self._insert(replacement)

          break

      if self._match((None,)):
        break

    return self._output

if __name__ == '__main__':
  converter = Converter(sys.stdin.read())
  sys.stdout.write(converter.convert())