Class: Rhythmmml::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/rhythmmml/parser.rb

Instance Method Summary collapse

Constructor Details

#initialize(sounds, sampling_rate, options = {}) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/rhythmmml/parser.rb', line 5

def initialize(sounds, sampling_rate, options={})
  pattern = /T\d+|V\d+|L\d+|[A-GR][#+-]?\d*\.?|O\d+|[><]|./i
  @sounds = sounds.scan(pattern)
  @sampling_rate = sampling_rate
  @bpm = options[:bpm] || 120
  @velocity = options[:velocity] || 5
  @octave = options[:octave] || 4
  @default_length = options[:default_length] || 4.0
  @octave_reverse = options[:octave_reverse] || false
  @cursor = 0
end

Instance Method Details

#parse ⇒ Object 



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# File 'lib/rhythmmml/parser.rb', line 17

def parse
  rhythm_infos = []
  @cursor.upto(@sounds.size - 1) do |i|
    sound = @sounds[i]
    base_sec = 60.0 * 4
    length = @default_length
    case sound
    when /\AT(\d+)/i
      @bpm = $1.to_i
      next
    when /\AV(\d+)/i
      @velocity = $1.to_i
      next
    when /\AL(\d+)/i
      @default_length = $1.to_f
      next
    when /\A([A-GR][#+-]?)(\d+)(\.)?/i
      length = $2.to_f
      sound = $1
      length = @default_length / 1.5 if $3
    when /\AO(\d+)/i
      @octave = $1.to_i
      next
    when "<"
      @octave += @octave_reverse ? -1 : 1
      next
    when ">"
      @octave -= @octave_reverse ? -1 : 1
      next
    end
    sec = base_sec / length / @bpm
    amplitude = @velocity.to_f / 10
    frequency = Mml2wav::Scale::FREQUENCIES[sound.downcase]
    next unless frequency
    frequency *= (2 ** @octave)
    rhythm_infos << [sound.downcase, sec, [frequency, @sampling_rate, sec, amplitude]]
    @cursor = i + 1
  end
  rhythm_infos
end