tone.rb

class Tone
	NAMES = ["C", "Cis/Des", "D", "Dis/Es", "E", "F", "Fis/Ges", "G", "Gis/As", "A", "Ais/B", "H" ]

	C	= 1
	Cis	= 2
	Des	= 2
	D	= 3
	Dis	= 4
	Es	= 4
	E	= 5
	F	= 6
	Fis	= 7
	Ges	= 7
	G	= 8
	Gis	= 9
	As	= 9
	A	= 10
	B	= 11
	Ais	= 11
	H	= 12

	def initialize(*args)
		@n = args[0]
	end

	def transpose!(ht)
		@n += ht + 12
		@n %= 12
	end

	def transpose(ht)
		Tone.new((@n + ht + 12) % 12, @gender)
	end

	def to_s
		NAMES[@n - 1]
	end

end

class Interval
	Unison		= 0
	MinorSecond	= 1
	MajorSecond	= 2
	MinorThird	= 3
	MajorThird	= 4
	PerfectForth	= 5
	DiminishedFifth	= 6
	AugmentedForth	= 6
	PerfectFifth	= 7
	MinorSixth	= 8
	MajorSixth	= 9
	MinorSeventh	= 10
	MajorSeventh	= 11
	Octave		= 12
end

class NoteArray
	def initialize(base, gender)
		@base = base
		@gender = gender
		@t = []
	end

	def transpose(ht)
		self.class.new(@base.transpose(ht), @gender)
	end

	def transpose!(ht)
		@t.each { |t| t.transpose!(ht) }
	end

	def to_s
		@t.join(" - ")
	end
end

class Triad < NoteArray
	Major		= 0
	Minor		= 1
	Diminished	= 2
	Augmented	= 3

	def initialize(base, gender)
		super base, gender

		if @gender == Major
			@t = [ @base.dup, @base.transpose(Interval::MajorThird), @base.transpose(Interval::MajorThird + Interval::MinorThird) ]
		elsif @gender == Minor
			@t = [ @base.dup, @base.transpose(Interval::MinorThird), @base.transpose(Interval::MinorThird + Interval::MajorThird) ]
		elsif @gender == Diminished
			@t = [ @base.dup, @base.transpose(Interval::MinorThird), @base.transpose(Interval::MinorThird + Interval::MinorThird) ]
		elsif @gender == Augmented
			@t = [ @base.dup, @base.transpose(Interval::MajorThird), @base.transpose(Interval::MajorThird + Interval::MajorThird) ]
		end
	end
end

class Scale < NoteArray
	Major		= 0
	Minor		= 1

	def initialize(base, gender)
		super base, gender

		if @gender == Major
			@ht = [ 3, 7 ]
		elsif @gender == Minor
			@ht = [ 2, 5 ]
		end

		t = @base.dup
		@t = [ t ]

		7.times do |n|
			if @ht.include? (n + 1)
				t = t.transpose(1)
			else
				t = t.transpose(2)
			end

			@t << t
		end
	end

	def relative_key
		if @gender == Scale::Major
			Scale.new(@base.transpose(-Interval::MinorThird), Scale::Minor)
		elsif @gender == Scale::Minor
			Scale.new(@base.transpose(-Interval::MinorThird), Scale::Major)
		end
	end
end

n = Tone.new(Tone::C)
puts Triad.new(n, Triad::Augmented).transpose(1)

12.times do |i|
	n = Tone.new(Tone::C + i)
	puts Scale.new(n, Scale::Major)
end