Module: Transcore::Command::Transpose

Defined in:
lib/transcore/command/transpose.rb

Constant Summary collapse

NEXT_TONE = 
{
  'A' => 'A#',
  'A#' => 'B',
  'B' => 'C',
  'C' => 'C#',
  'C#' => 'D',
  'D' => 'D#',
  'D#' => 'E',
  'E' => 'F',
  'F' => 'F#',
  'F#' => 'G',
  'G' => 'G#',
  'G#' => 'A'
}

Class Method Summary collapse

Class Method Details

.parse_opts(_argv) ⇒ Object 



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# File 'lib/transcore/command/transpose.rb', line 19

def self.parse_opts(_argv)
  {}
end

.run(argv, input_stream = $stdin, output_stream = $stdout) ⇒ Object 



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# File 'lib/transcore/command/transpose.rb', line 23

def self.run(argv, input_stream = $stdin, output_stream = $stdout)
  step = (argv.shift || 1).to_i
  input = input_stream.read

  input.gsub!(/　/, '  ')
  input.gsub!(/ +$/, '')
  input.gsub!(/(^|\s|\/|on)([ACDFG])＃/, '\\1\\2#')

  input.gsub!(/(^|\s|\/|on)A♭/, '\\1G#')
  input.gsub!(/(^|\s|\/|on)B♭/, '\\1A#')
  input.gsub!(/(^|\s|\/|on)D♭/, '\\1C#')
  input.gsub!(/(^|\s|\/|on)E♭/, '\\1D#')
  input.gsub!(/(^|\s|\/|on)G♭/, '\\1F#')
  step %= 12
  rest = input
  step.times do |_i|
    next_str = ''
    while /(^|\s|\/|on)(A#|A|B|C#|C|D#|D|E|F#|F|G#|G)/ =~ rest
      next_str += $` + Regexp.last_match[1]
      match_str = Regexp.last_match[2]
      rest = $'
      next_str += NEXT_TONE[match_str]
    end
    rest = next_str + rest
  end
  result = rest

  output_stream.puts result
  0
end