Class: HeadMusic::Content::CantusFirmus::Example

Inherits:
Object
  • Object
show all
Defined in:
lib/head_music/content/cantus_firmus/example.rb

Overview

Sample cantus firmus examples from various pedagogical sources.

Constant Summary collapse

EXAMPLES_DATA = 
YAML.load_file(File.expand_path("examples.yml", __dir__)).freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data:) ⇒ Example

Returns a new instance of Example.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 42

def initialize(data:)
  @slug = data["slug"]
  @source = Source.get(data["source"])
  @tonal_center = data["tonal_center"]
  @mode = data["mode"]&.to_sym
  @pitches = data["pitches"] || []
end

Instance Attribute Details

#mode ⇒ Object (readonly)

Returns the value of attribute mode.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 8

def mode
  @mode
end

#pitches ⇒ Object (readonly)

Returns the value of attribute pitches.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 8

def pitches
  @pitches
end

#slug ⇒ Object (readonly)

Returns the value of attribute slug.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 8

def slug
  @slug
end

#source ⇒ Object (readonly)

Returns the value of attribute source.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 8

def source
  @source
end

#tonal_center ⇒ Object (readonly)

Returns the value of attribute tonal_center.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 8

def tonal_center
  @tonal_center
end

Class Method Details

.all ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 11

def all
  @all ||= EXAMPLES_DATA["cantus_firmus_examples"].map do |data|
    new(data: data)
  end
end

.by_mode(mode_name) ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 32

def by_mode(mode_name)
  normalized_mode = mode_name.to_s.downcase
  all.select { |example| example.mode.to_s.downcase == normalized_mode }
end

.by_source(source_identifier) ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 21

def by_source(source_identifier)
  source = Source.get(source_identifier)
  return [] unless source

  all.select { |example| example.source == source }
end

.by_tonal_center(tonal_center_name) ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 37

def by_tonal_center(tonal_center_name)
  all.select { |example| example.tonal_center.to_s == tonal_center_name.to_s }
end

.find_by_slug(slug) ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 17

def find_by_slug(slug)
  all.find { |example| example.slug == slug.to_s }
end

.sources ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 28

def sources
  all.map(&:source).uniq
end

Instance Method Details

#key_signature_name ⇒ Object

The mode named on its own tonal center, which KeySignature reads as a collection while retaining the scale type.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 67

def key_signature_name
  [tonal_center, mode].compact.join(" ")
end

#length ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 50

def length
  pitches.length
end

#to_flow(rhythmic_value: :whole, meter: "4/4") ⇒ Object

An example is a catalog datum -- a pitch list with a mode and a citation -- not content, so rhythm and meter are the realization's choice rather than the datum's, and are parameters.



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 57

def to_flow(rhythmic_value: :whole, meter: "4/4")
  flow = HeadMusic::Content::Flow.new(name: to_s, key_signature: key_signature_name, meter: meter)
  flow.source = source
  voice = flow.add_voice(role: "cantus firmus")
  pitches.each_with_index { |pitch, index| voice.place("#{index + 1}:1", rhythmic_value, pitch) }
  flow
end

#to_s ⇒ Object 



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# File 'lib/head_music/content/cantus_firmus/example.rb', line 71

def to_s
  "#{tonal_center} #{mode} (#{source})"
end