Class: Roka::Converter

Inherits:
Object
  • Object
show all
Defined in:
lib/roka/converter.rb

Constant Summary collapse

VOWELS_INDEX = 
%w[a  i  u  e  o ]
VOWELS_KANA = 
%w[ア イ ウ エ オ]
SOUND_CHANGES = 
{
  'ts' => %w[ツァ ツィ ツ   ツェ ツォ],

  'xy' => %w[ャ   ィ   ュ   ェ   ョ  ],
  'x'  => %w[ァ   ィ   ゥ   ェ   ォ  ],

  'k'  => %w[カ   キ   ク   ケ   コ  ],
  's'  => %w[サ   シ   ス   セ   ソ  ],
  't'  => %w[タ   チ   ツ   テ   ト  ],
  'n'  => %w[ナ   ニ   ヌ   ネ   ノ  ],
  'h'  => %w[ハ   ヒ   フ   ヘ   ホ  ],
  'm'  => %w[マ   ミ   ム   メ   モ  ],
  'y'  => %w[ヤ   イ   ユ   イェ ヨ  ],
  'r'  => %w[ラ   リ   ル   レ   ロ  ],
  'l'  => %w[ラ   リ   ル   レ   ロ  ],
  'w'  => %w[ワ   ウィ ウ   ウェ ヲ  ],

  'g'  => %w[ガ   ギ   グ   ゲ   ゴ  ],
  'z'  => %w[ザ   ジ   ズ   ゼ   ゾ  ],
  'j'  => %w[ジャ ジ   ジュ ジェ ジョ],
  'd'  => %w[ダ   ヂ   ヅ   デ   ド  ],
  'b'  => %w[バ   ビ   ブ   ベ   ボ  ],
  'v'  => %w[ヴァ ヴィ ヴ   ヴェ ヴォ],

  'f'  => %w[ファ フィ フ   フェ フォ],
  'p'  => %w[パ   ピ   プ   ペ   ポ  ],

  'c'  => %w[カ   シ   ク   セ   コ  ],
}
PREFIX_CHANGES = 
{
  /^([kg])w([aeiou])/              => '\1ux\2',
  /^([td])w([aeiou])/              => '\1ox\2',
  /^sh([aeiou])/                   => 'sixy\1',
  /^ch([aeiou])/                   => 'tixy\1',
  /^([kgszjtcdnhbpmrl])y([aeiou])/ => '\1ixy\2',
  /^([td])h([aeiou])/              => '\1exy\2',
  /^([^aeioun])\1/                 => 'xtu\1',
  /^nn\b/                          => 'n',
  /^([^aeiou]o)([^h]?)\b/          => '\1h\2',
}
EXCEPTIONS = 
{
  '-'    => 'ー',
  'xka'  => 'ヵ',
  'xke'  => 'ヶ',
  'xtu'  => 'ッ',
  'xtsu' => 'ッ',
  'xwa'  => 'ヮ',
  'shi'  => 'シ',
  'chi'  => 'チ',
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(str) ⇒ Converter

Returns a new instance of Converter.



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# File 'lib/roka/converter.rb', line 63

def initialize(str)
  @buffer     = regulate(str)
  @determined = []
end

Instance Attribute Details

#determined ⇒ Object (readonly)

Returns the value of attribute determined.



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# File 'lib/roka/converter.rb', line 61

def determined
  @determined
end

Instance Method Details

#consume(len, replacement = nil) ⇒ Object 



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# File 'lib/roka/converter.rb', line 145

def consume(len, replacement = nil)
  replacement = @buffer[0...len] if replacement.nil?
  @determined << replacement if replacement
  @buffer = @buffer[len..-1].to_s
  true
end

#convert ⇒ Object 



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# File 'lib/roka/converter.rb', line 68

def convert
  return if eos?
  parse && convert
end

#eos? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/roka/converter.rb', line 172

def eos?
  @buffer.empty?
end

#expand_long_sound(prefix, vowel) ⇒ Object 



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# File 'lib/roka/converter.rb', line 152

def expand_long_sound(prefix, vowel)
  c = @buffer[0]

  case vowel
  when 'o'
    if 'h' == c && !@buffer[1]
      consume(1, ['', 'ウ'])
    elsif 'h' == c
      d, _ = peak
      if d[0] == 'h'
        consume(1, ['', 'オ'])
      end
    elsif !(VOWELS_INDEX + %w[y]).include?(c) && ('n' == c && 'o' == @buffer[1])
      @determined << ['', 'オ', 'ウ']
    end
  when 'u'
    @determined << ['', 'ウ'] if 'y' == prefix
  end
end

#parse ⇒ Object 



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# File 'lib/roka/converter.rb', line 73

def parse
  parse_exception \
    || parse_prefix \
    || parse_sound \
    || parse_vowel \
    || parse_last
end

#parse_exception ⇒ Object 



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# File 'lib/roka/converter.rb', line 81

def parse_exception
  EXCEPTIONS.each do |seq, replacement|
    if @buffer.start_with?(seq)
      consume(seq.size, replacement)
      return true
    end
  end

  false
end

#parse_last ⇒ Object 



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# File 'lib/roka/converter.rb', line 137

def parse_last
  if 'n' == @buffer[0]
    consume(1, 'ン')
  else
    consume(1, @buffer[0])
  end
end

#parse_prefix ⇒ Object 



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# File 'lib/roka/converter.rb', line 92

def parse_prefix
  PREFIX_CHANGES.each do |pattern, replacement|
    buffer = @buffer.sub(pattern, replacement)

    unless buffer == @buffer
      @buffer = buffer
      return true
    end
  end

  false
end

#parse_sound ⇒ Object 



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# File 'lib/roka/converter.rb', line 105

def parse_sound
  SOUND_CHANGES.each do |prefix, changes|
    if @buffer.start_with?(prefix)
      l = prefix.size
      vowel = @buffer[l]

      if (i = VOWELS_INDEX.index(vowel))
        if 'n' == @buffer[0] && 'x' != @buffer[l + 1] && 'ン' != @determined[@determined.size - 1]
          consume(l + 1, ['ン' + VOWELS_KANA[i], changes[i]])
        else
          consume(l + 1, changes[i])
        end
        expand_long_sound(prefix, vowel)
        return true
      end
    end
  end

  false
end

#parse_vowel(consonant = nil) ⇒ Object 



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# File 'lib/roka/converter.rb', line 126

def parse_vowel(consonant = nil)
  vowel = @buffer[0]
  if (i = VOWELS_INDEX.index(vowel))
    consume(1, VOWELS_KANA[i])
    expand_long_sound(nil, vowel)
    true
  else
    false
  end
end

#peak(_buffer = nil) ⇒ Object 



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# File 'lib/roka/converter.rb', line 194

def peak(_buffer = nil)
  determined  = @determined
  buffer      = @buffer
  @determined = []
  @buffer = _buffer unless _buffer.nil?
  parse while @determined.empty? || !eos?
  [@determined, @buffer]
ensure
  @determined = determined
  @buffer     = buffer
end

#regulate(str) ⇒ Object 



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# File 'lib/roka/converter.rb', line 190

def regulate(str)
  NKF.nkf('-m0 -Z1 -w', str.to_s.downcase)
end

#results ⇒ Object 



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# File 'lib/roka/converter.rb', line 176

def results
  tree = ['']

  @determined.each do |det|
    if det.is_a?(Array)
      tree = tree.product(det).map(&:join)
    else
      tree.each { |t| t << det }
    end
  end

  tree
end