Class: HeadMusic::Style::Analysis

Inherits:
Object
  • Object
show all
Defined in:
lib/head_music/style/analysis.rb

Overview

An analysis of music according to a style guide.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(guide, voice) ⇒ Analysis

Any object answering analyze(voice) is a guide here – a guide class, a Guides::Configured, or a test double. Checking at construction keeps a missed Guide.get lookup from surfacing as NoMethodError on nil far away.



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# File 'lib/head_music/style/analysis.rb', line 11

def initialize(guide, voice)
  unless guide.respond_to?(:analyze)
    raise ArgumentError, "guide must respond to #analyze (got #{guide.inspect})"
  end

  @guide = guide
  @voice = voice
end

Instance Attribute Details

#guide ⇒ Object (readonly)

Returns the value of attribute guide.



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# File 'lib/head_music/style/analysis.rb', line 6

def guide
  @guide
end

#voice ⇒ Object (readonly)

Returns the value of attribute voice.



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# File 'lib/head_music/style/analysis.rb', line 6

def voice
  @voice
end

Instance Method Details

#adherent? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/head_music/style/analysis.rb', line 38

def adherent?
  annotations.all?(&:adherent?)
end

#annotations ⇒ Object 



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# File 'lib/head_music/style/analysis.rb', line 25

def annotations
  @annotations ||= @guide.analyze(voice)
end

#fitness ⇒ Object

The grade: sufficiency gates multiply against a weighted average of the rubric rules, so an insufficient exercise scales the whole grade down while ordinary rules trade off against each other by weight.



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# File 'lib/head_music/style/analysis.rb', line 32

def fitness
  return 1.0 if annotations.empty?

  @fitness ||= gate_factor * rubric_fitness
end

#gate_factor ⇒ Object (private) 



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# File 'lib/head_music/style/analysis.rb', line 44

def gate_factor
  gates.map(&:fitness).reduce(1, :*)
end

#gates ⇒ Object (private) 



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# File 'lib/head_music/style/analysis.rb', line 56

def gates
  annotations.select(&:gate?)
end

#messages ⇒ Object Also known as: annotation_messages 



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# File 'lib/head_music/style/analysis.rb', line 20

def messages
  annotations.reject(&:adherent?).map(&:message)
end

#rubric_fitness ⇒ Object (private) 



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# File 'lib/head_music/style/analysis.rb', line 48

def rubric_fitness
  rubric = annotations.reject(&:gate?)
  total_weight = rubric.sum(&:weight)
  return 1.0 if rubric.empty? || total_weight.zero?

  rubric.sum { |annotation| annotation.weight * annotation.fitness } / total_weight
end