Class: Coltrane::Theory::Interval

Inherits:
IntervalClass show all
Defined in:
lib/coltrane/theory/interval.rb

Constant Summary

Constants inherited from IntervalClass

Coltrane::Theory::IntervalClass::ALTERATIONS, Coltrane::Theory::IntervalClass::COMPOUND_DISTANCES_NAMES, Coltrane::Theory::IntervalClass::DISTANCES_NAMES, Coltrane::Theory::IntervalClass::QUALITY_NAMES, Coltrane::Theory::IntervalClass::QUALITY_SEQUENCE, Coltrane::Theory::IntervalClass::SINGLE_DISTANCES_NAMES

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from IntervalClass

#+, #-, #-@, #==, all_names_including_compound, #alteration, #compound_interval, #compound_name, compound_names, #distance, distance_name, distances_names, expand_name, #full_name, full_names, full_names_including_compound, #interval, #inversion, names, #quality, quality_name, split

Methods inherited from FrequencyInterval

#+, #-, #-@, #<=>, #==, #ascending?, #descending?, #inversion, #semitones

Constructor Details

#initialize(arg_1 = nil, arg_2 = nil, ascending: true, letter_distance: nil, semitones: nil, compound: false) ⇒ Interval

Returns a new instance of Interval.



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# File 'lib/coltrane/theory/interval.rb', line 40

def initialize(arg_1 = nil, arg_2 = nil, ascending: true,
               letter_distance: nil,
               semitones: nil,
               compound: false)
  if arg_1 && !arg_2 # assumes arg_1 is a letter
    @compound = compound
    IntervalClass[arg_1].interval.yield_self do |interval|
      @letter_distance = interval.letter_distance
      @cents = interval.cents
    end
  elsif arg_1 && arg_2 # assumes those are notes
    if ascending
      @compound = compound
      @cents =
        (arg_1.frequency / arg_2.frequency)
        .interval_class
        .cents

      @letter_distance = calculate_letter_distance arg_1.letter,
                                                   arg_2.letter,
                                                   ascending
    else
      self.class.new(arg_1, arg_2).descending.yield_self do |base_interval|
        @compound        = base_interval.compound?
        @cents           = base_interval.cents
        @letter_distance = base_interval.letter_distance
      end
    end
  elsif letter_distance && semitones
    @compound        = compound || letter_distance > 8
    @cents           = semitones * 100
    @letter_distance = letter_distance
  else
    raise WrongKeywordsError,
          '[interval_class_name]' \
          'Provide: [first_note, second_note] || ' \
          '[letter_distance:, semitones:]'
  end
end

Instance Attribute Details

#cents ⇒ Object (readonly)

Returns the value of attribute cents.



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# File 'lib/coltrane/theory/interval.rb', line 6

def cents
  @cents
end

#letter_distance ⇒ Object (readonly)

Returns the value of attribute letter_distance.



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# File 'lib/coltrane/theory/interval.rb', line 6

def letter_distance
  @letter_distance
end

Class Method Details

.[](arg) ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 80

def self.[](arg)
  new(arg)
end

.all ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 10

def all
  @all ||= super.map(&:interval)
end

.all_augmented ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 22

def all_augmented
  @all_augmented ||= all_including_compound.select(&:has_augmented?)
                                           .map(&:augmented)
end

.all_compound ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 14

def all_compound
  @all_compound ||= all.map(&:compound)
end

.all_diminished ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 27

def all_diminished
  @all_diminished ||= all_including_compound.select(&:has_diminished?)
                                            .map(&:diminished)
end

.all_including_compound ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 18

def all_including_compound
  @all_including_compound ||= all + all_compound
end

.all_including_compound_and_altered ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 32

def all_including_compound_and_altered
  @all_including_compound_and_altered ||=
    all_including_compound +
    all_diminished +
    all_augmented
end

Instance Method Details

#accidentals ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 100

def accidentals
  if distance_to_starting.positive? then 'A' * distance_to_starting.abs
  elsif distance_to_starting.negative? then 'd' * distance_to_starting.abs
  else ''
  end
end

#as(n) ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 117

def as(n)
  i = clone(letter_distance: n)
  i if i.name.match?(n.to_s)
end

#as!(n) ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 122

def as!(n)
  i = as(n)
  i unless i&.name&.match? /d|A/
end

#as_augmented(n = 1) ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 131

def as_augmented(n = 1)
  as(letter_distance - n)
end

#as_diminished(n = 1) ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 127

def as_diminished(n = 1)
  as(letter_distance + n)
end

#ascending ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 159

def ascending
  ascending? ? self : opposite
end

#augment(n = 1) ⇒ Object Also known as: augmented 



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# File 'lib/coltrane/theory/interval.rb', line 149

def augment(n = 1)
  clone(semitones: semitones + n)
end

#clone(override_args = {}) ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 135

def clone(override_args = {})
  self.class.new({
    semitones: semitones,
    letter_distance: letter_distance,
    compound: compound?
  }.merge(override_args))
end

#descending ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 163

def descending
  descending? ? self : opposite
end

#diminish(n = 1) ⇒ Object Also known as: diminished 



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# File 'lib/coltrane/theory/interval.rb', line 143

def diminish(n = 1)
  clone(semitones: semitones - n)
end

#has_augmented? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/coltrane/theory/interval.rb', line 92

def has_augmented?
  name.match? /M|P|A/
end

#has_diminished? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/coltrane/theory/interval.rb', line 96

def has_diminished?
  name.match? /m|P|d/
end

#interval_class ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 84

def interval_class
  FrequencyInterval[cents].interval_class
end

#name ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 107

def name
  @name ||= begin
    if distance_to_starting.zero? || distance_to_starting.abs > 2
      compound? ? interval_class.compound_name : interval_class.name
    else
      "#{accidentals}#{starting_interval.distance + (compound? ? 7 : 0)}"
    end
  end
end

#opposite ⇒ Object 



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# File 'lib/coltrane/theory/interval.rb', line 155

def opposite
  clone(semitones: -semitones, letter_distance: (-letter_distance % 8) + 1)
end