Class: OutroRails::VoicingStubGenerator

Inherits:
Object
  • Object
show all
Includes:
VoicingSeedWriter
Defined in:
lib/outro_rails/generators/voicing_stub_generator.rb

Overview

Builds stub voicing seed files for a chord entry (a hash loaded from db/seeds/chords/*.yml).

Constant Summary collapse

INSTRUMENTS =

The instruments stubs can be generated for, as symbols - the rake task iterates this list and branches on instrument == :guitar.

OutroRails::Instruments::ENUM_VALUES.keys
LOWEST_C_MIDI =

Piano stubs place the first note in the octave above this pitch.

Theory::Pitch.parse("C3").midi

Instance Attribute Summary

Attributes included from VoicingSeedWriter

#chord

Instance Method Summary collapse

Methods included from VoicingSeedWriter

#root, #symbol

Constructor Details

#initialize(chord) ⇒ VoicingStubGenerator

Takes the chord seed entry to generate stubs for



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# File 'lib/outro_rails/generators/voicing_stub_generator.rb', line 22

def initialize(chord)
  @chord = chord
end

Instance Method Details

#filename(instrument) ⇒ Object

Seed filename for one instrument, e.g. "c-major-7-piano.yml"



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# File 'lib/outro_rails/generators/voicing_stub_generator.rb', line 27

def filename(instrument)
  "#{chord.fetch('slug')}-#{instrument}.yml"
end

#note_names ⇒ Object

Normalized chord tones, e.g. E7#9 => [E, G#, B, D, F##->G]



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# File 'lib/outro_rails/generators/voicing_stub_generator.rb', line 37

def note_names
  chord.fetch("intervals").map { |interval| root.at_interval(interval) }
end

#relative_path(instrument) ⇒ Object

That filename under the root's directory, e.g. "c/c-major-7-piano.yml"



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# File 'lib/outro_rails/generators/voicing_stub_generator.rb', line 32

def relative_path(instrument)
  File.join(root.path_slug, filename(instrument))
end

#stub_yaml(instrument) ⇒ Object

Piano: one entry per inversion Guitar: a single root-position stub to fill in manually



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# File 'lib/outro_rails/generators/voicing_stub_generator.rb', line 43

def stub_yaml(instrument)
  instrument = instrument.to_sym
  unless INSTRUMENTS.include?(instrument)
    raise ArgumentError,
          "unknown instrument #{instrument.inspect} " \
          "(expected #{INSTRUMENTS.join(' or ')})"
  end

  case instrument
  when :piano
    chord_tones.each_index.map do |position|
      entry_yaml(instrument, chord_tones.rotate(position), position + 1)
    end.join("\n")
  when :guitar
    entry_yaml(instrument, chord_tones)
  end
end