Class: Coltrane::Theory::Progression

Inherits:
Object
  • Object
show all
Extended by:
NotableProgressions
Includes:
Changes
Defined in:
lib/coltrane/theory/progression.rb

Overview

Allows the creation of chord progressions using standard notations. Ex: Progression.new(‘I-IV-V’, key: ‘Am’)

Constant Summary

Constants included from NotableProgressions

NotableProgressions::PROGRESSIONS

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Changes

#bird_changes, #coltrane_changes

Constructor Details

#initialize(notation = nil, chords: nil, roman_chords: nil, key: nil, scale: nil) ⇒ Progression

Returns a new instance of Progression.



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# File 'lib/coltrane/theory/progression.rb', line 30

def initialize(notation = nil, chords: nil, roman_chords: nil, key: nil, scale: nil)
  if notation.nil? && chords.nil? && roman_chords.nil? || key.nil? && scale.nil?
    raise WrongKeywordsError,
      '[chords:, [scale: || key:]] '\
      '[roman_chords:, [scale: || key:]] '\
      '[notation:, [scale: || key:]] '\
  end

  @scale  = scale || Key[key]
  @chords =
    if !chords.nil?
      chords
    elsif !roman_chords.nil?
      roman_chords.map(&:chord)
    elsif !notation.nil?
      @notation = notation
      notation.split('-').map { |c| RomanChord.new(c, scale: @scale).chord }
    end
end

Instance Attribute Details

#chords ⇒ Object (readonly)

Returns the value of attribute chords.



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

def chords
  @chords
end

#notation ⇒ Object (readonly)

Returns the value of attribute notation.



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

def notation
  @notation
end

#scale ⇒ Object (readonly)

Returns the value of attribute scale.



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

def scale
  @scale
end

Class Method Details

.find(*chords) ⇒ Object 



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# File 'lib/coltrane/theory/progression.rb', line 12

def self.find(*chords)
  chords
    .yield_self { |chords|
      next chords if chords[0].is_a?(Chord)
      chords.map {|c| Chord.new(name: c) }
    }
    .yield_self { |chords|
      NoteSet[*chords.map(&:root_note)]
      .yield_self { |root_notes|
        Scale.having_notes(*root_notes).strict_scales
      }
      .reduce([]) { |memo, scale|
        memo + [Progression.new(chords: chords, scale: scale)]
      }
    }
    .yield_self { |progressions| ProgressionSet.new(*progressions) }
end

Instance Method Details

#interval_sequence ⇒ Object 



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# File 'lib/coltrane/theory/progression.rb', line 50

def interval_sequence
  @interval_sequence ||= IntervalSequence(notes: @root_notes)
end

#notes ⇒ Object 



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# File 'lib/coltrane/theory/progression.rb', line 68

def notes
  NoteSet[*chords.map(&:notes).map(&:notes).flatten]
end

#notes_out ⇒ Object 



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# File 'lib/coltrane/theory/progression.rb', line 72

def notes_out
  notes - scale.notes
end

#notes_out_size ⇒ Object 



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# File 'lib/coltrane/theory/progression.rb', line 76

def notes_out_size
  notes_out.size
end

#roman_chords ⇒ Object 



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# File 'lib/coltrane/theory/progression.rb', line 58

def roman_chords
  @roman_chords ||= chords.map do |c|
    RomanChord.new(chord: c, scale: scale)
  end
end

#root_notes ⇒ Object 



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# File 'lib/coltrane/theory/progression.rb', line 54

def root_notes
  @root_notes ||= @chords.map(&:root_note)
end