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Contents
module Coltrane
module Theory
class GreekMode < Scale
attr_reader :mode
MODES = %w[
Ionian
Dorian
Phrygian
Lydian
Mixolydian
Aeolian
Locrian
].freeze
LETTER_SEQUENCE = %w[C D E F G A B].freeze
def initialize(mode, tone)
super name: mode.capitalize, notes: begin
@mode = mode.to_s
@tone = Note[tone]
base_major_notes
.rotate(mode_index)
.zip(letter_sequence)
.map { |(note, letter)| note.as(letter) }
end
end
private
def letter_sequence
LETTER_SEQUENCE.yield_self { |seq| seq.rotate(seq.index(tone.letter))}
end
def mode_index
@mode_index ||= MODES.map(&:downcase).index(mode.to_s)
end
def base_major_notes
base_scale = DiatonicScale.new(Note['C']).notes
base_interval = base_scale[0] - base_scale[mode_index]
DiatonicScale.new(Note[tone] - base_interval).notes
end
end
end
end
Version data entries
11 entries across 11 versions & 1 rubygems