Module: Coltrane::ClassicScales

Included in:
Scale
Defined in:
lib/coltrane/classic_scales.rb

Overview

This module deals with well known scales on music

Constant Summary collapse

SCALES = 
{
  'Major'            => [2, 2, 1, 2, 2, 2, 1],
  'Pentatonic Major' => [2, 2, 3, 2, 3],
  'Blues Major'      => [2, 1, 1, 3, 2, 3],
  'Natural Minor'    => [2, 1, 2, 2, 1, 2, 2],
  'Harmonic Minor'   => [2, 1, 2, 2, 1, 3, 1],
  'Hungarian Minor'  => [2, 1, 2, 1, 1, 3, 1],
  'Pentatonic Minor' => [3, 2, 2, 3, 2],
  'Blues Minor'      => [3, 2, 1, 1, 3, 2],
  'Whole Tone'       => [2, 2, 2, 2, 2, 2],
  'Flamenco'         => [1, 3, 1, 2, 1, 2, 2],
  'Chromatic'        => [1]*12
}.freeze
MODES = 
{
  'Major' => %w[Ionian Dorian Phrygian Lydian Mixolydian Aeolian Locrian]
}.freeze

Instance Method Summary collapse

Instance Method Details

#fetch(name, tone = nil) ⇒ Object 



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# File 'lib/coltrane/classic_scales.rb', line 55

def fetch(name, tone = nil)
  Coltrane::Scale.public_send(name, tone)
end

#from_key(key) ⇒ Object 



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# File 'lib/coltrane/classic_scales.rb', line 59

def from_key(key)
  key_regex = /([A-G][#b]?)([mM]?)/
  _, note, s = *key.match(key_regex)
  scale = s == 'm' ? :minor : :major
  Scale.public_send(scale, note)
end

#having_chords(*chords) ⇒ Object Also known as: having_chord 



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# File 'lib/coltrane/classic_scales.rb', line 91

def having_chords(*chords)
  should_create = !chords.first.is_a?(Chord)
  notes = chords.reduce(NoteSet[]) do |memo, c|
    memo + (should_create ? Chord.new(name: c) : c).notes
  end
  having_notes(notes)
end

#having_notes(notes) ⇒ Object

Will output a OpenStruct like the following: {

scales: [array of scales]
results: {
  scale_name: {
    note_number => found_notes
  }
}

}



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# File 'lib/coltrane/classic_scales.rb', line 76

def having_notes(notes)
  format = { scales: [], results: {} }
  OpenStruct.new(
    standard_scales.each_with_object(format) do |(name, intervals), output|
      Note.all.each.map do |tone|
        scale = new(*intervals, tone: tone, name: scale)
        output[:results][name] ||= {}
        next if output[:results][name].key?(tone.number)
        output[:scales] << scale if scale.include?(notes)
        output[:results][name][tone.number] = scale.notes & notes
      end
    end
  )
end

#known_scales ⇒ Object 



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# File 'lib/coltrane/classic_scales.rb', line 46

def known_scales
  SCALES.keys
end

#standard_scales ⇒ Object

All but the chromatic



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# File 'lib/coltrane/classic_scales.rb', line 51

def standard_scales
  SCALES.reject { |k,v| k == 'Chromatic' }
end