Class: Coltrane::Scale

Inherits:
Object
  • Object
show all
Extended by:
ClassicScales
Defined in:
lib/coltrane/scale.rb

Overview

Musical scale creation and manipulation

Constant Summary

Constants included from ClassicScales

ClassicScales::MODES, ClassicScales::SCALES

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from ClassicScales

fetch, from_key, having_chords, having_notes, known_scales, standard_scales

Constructor Details

#initialize(*distances, tone: 'C', mode: 1, name: nil, notes: nil) ⇒ Scale

Returns a new instance of Scale.



9
10
11
12
13
14
15
16
17
18
19
20
21
 
# File 'lib/coltrane/scale.rb', line 9

def initialize(*distances, tone: 'C', mode: 1, name: nil, notes: nil)
  @name = name
  if distances.any? && tone
    @tone              = Note[tone]
    distances          = distances.rotate(mode - 1)
    @interval_sequence = IntervalSequence.new(distances: distances)
  elsif notes
    ds = NoteSet[*notes].interval_sequence.distances
    new(*ds, tone: notes.first)
  else
    raise WrongKeywordsError, '[*distances, tone: "C", mode: 1] || [notes:]'
  end
end

Instance Attribute Details

#interval_sequence ⇒ Object (readonly)

Returns the value of attribute interval_sequence.



7
8
9
 
# File 'lib/coltrane/scale.rb', line 7

def interval_sequence
  @interval_sequence
end

#tone ⇒ Object (readonly)

Returns the value of attribute tone.



7
8
9
 
# File 'lib/coltrane/scale.rb', line 7

def tone
  @tone
end

Instance Method Details

#&(other) ⇒ Object

Raises:



69
70
71
72
 
# File 'lib/coltrane/scale.rb', line 69

def &(other)
  raise HasNoNotesError unless other.respond_to?(:notes)
  notes & other
end

#chords(size = 3..12) ⇒ Object Also known as: all_chords 



122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
 
# File 'lib/coltrane/scale.rb', line 122

def chords(size = 3..12)
  size = (size..size) if size.is_a?(Integer)
  scale_rotations = interval_sequence.inversions
  ChordQuality.intervals_per_name.reduce([]) do |memo1, (qname, qintervals)|
    next memo1 unless size.include?(qintervals.size)
    memo1 + scale_rotations.each_with_index
                           .reduce([]) do |memo2, (rot, index)|
      if (rot & qintervals).size == qintervals.size
        memo2 + [Chord.new(root_note: degree(index + 1),
                           quality: ChordQuality.new(name: qname))]
      else
        memo2
      end
    end
  end
end

#degree(d) ⇒ Object Also known as: []

Raises:



49
50
51
52
 
# File 'lib/coltrane/scale.rb', line 49

def degree(d)
  raise WrongDegreeError, d if d < 1 || d > size
  tone + interval_sequence[d - 1].semitones
end

#degree_of_chord(chord) ⇒ Object 



60
61
62
63
 
# File 'lib/coltrane/scale.rb', line 60

def degree_of_chord(chord)
  return if chords(chord.size).map(&:name).include?(chord.name)
  degree_of_note(chord.root_note)
end

#degree_of_note(note) ⇒ Object 



65
66
67
 
# File 'lib/coltrane/scale.rb', line 65

def degree_of_note(note)
  notes.index(note)
end

#degrees ⇒ Object 



56
57
58
 
# File 'lib/coltrane/scale.rb', line 56

def degrees
  (1..size)
end

#id ⇒ Object 



23
24
25
 
# File 'lib/coltrane/scale.rb', line 23

def id
  [(name || @interval_sequence), tone.number]
end

#include_notes?(arg) ⇒ Boolean Also known as: include?

Returns:

  • (Boolean) 


74
75
76
77
 
# File 'lib/coltrane/scale.rb', line 74

def include_notes?(arg)
  noteset = arg.is_a?(Note) ? NoteSet[arg] : arg
  (self & noteset).size == noteset.size
end

#interval(i) ⇒ Object 



85
86
87
 
# File 'lib/coltrane/scale.rb', line 85

def interval(i)
  interval_sequence[(i - 1) % size]
end

#name ⇒ Object 



27
28
29
30
31
32
33
34
35
36
37
 
# File 'lib/coltrane/scale.rb', line 27

def name
  @name = begin
    is = interval_sequence.distances
    (0...is.size).each do |i|
      if (scale_name = Coltrane::ClassicScales::SCALES.key(is.rotate(i)))
        return scale_name
      end
    end
    nil
  end
end

#notes ⇒ Object 



81
82
83
 
# File 'lib/coltrane/scale.rb', line 81

def notes
  NoteSet[*degrees.map { |d| degree(d) }]
end

#pentads ⇒ Object 



114
115
116
 
# File 'lib/coltrane/scale.rb', line 114

def pentads
  tertians(5)
end

#pretty_name ⇒ Object Also known as: full_name 



43
44
45
 
# File 'lib/coltrane/scale.rb', line 43

def pretty_name
  "#{tone.name} #{name}"
end

#progression(*degrees) ⇒ Object 



118
119
120
 
# File 'lib/coltrane/scale.rb', line 118

def progression(*degrees)
  Progression.new(self, degrees)
end

#sevenths ⇒ Object 



110
111
112
 
# File 'lib/coltrane/scale.rb', line 110

def sevenths
  tertians(4)
end

#size ⇒ Object 



89
90
91
 
# File 'lib/coltrane/scale.rb', line 89

def size
  interval_sequence.size
end

#tertians(n = 3) ⇒ Object 



93
94
95
96
97
98
99
100
101
102
103
104
 
# File 'lib/coltrane/scale.rb', line 93

def tertians(n = 3)
  degrees.size.times.reduce([]) do |memo, d|
    ns = NoteSet[ *Array.new(n) { |i| notes[(d + (i * 2)) % size] } ]
    begin
      chord = Chord.new(notes: ns)
    rescue ChordNotFoundError
      memo
    else
      memo + [chord]
    end
  end
end

#to_s ⇒ Object 



39
40
41
 
# File 'lib/coltrane/scale.rb', line 39

def to_s
  "#{tone} #{name}"
end

#triads ⇒ Object 



106
107
108
 
# File 'lib/coltrane/scale.rb', line 106

def triads
  tertians(3)
end