Class: HeadMusic::DiatonicInterval::Parser

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

Overview

Interprets a string or symbol

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(identifier) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/head_music/diatonic_interval.rb', line 50

def initialize(identifier)
  @identifier = expand(identifier)
end

Instance Attribute Details

#identifier ⇒ Object (readonly)

Returns the value of attribute identifier.



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# File 'lib/head_music/diatonic_interval.rb', line 48

def identifier
  @identifier
end

Instance Method Details

#degree_name ⇒ Object 



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# File 'lib/head_music/diatonic_interval.rb', line 62

def degree_name
  words.last
end

#expand(identifier) ⇒ Object 



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# File 'lib/head_music/diatonic_interval.rb', line 74

def expand(identifier)
  if /[A-Z]\d{1,2}/i.match?(identifier)
    number = NUMBER_NAMES[identifier.gsub(/[A-Z]/i, "").to_i - 1]
    return [quality_for(identifier[0]), number].join("_").to_sym
  end
  identifier
end

#higher_letter ⇒ Object 



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# File 'lib/head_music/diatonic_interval.rb', line 70

def higher_letter
  HeadMusic::Pitch.middle_c.letter_name.steps_up(steps)
end

#quality_for(abbreviation) ⇒ Object 



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# File 'lib/head_music/diatonic_interval.rb', line 82

def quality_for(abbreviation)
  QUALITY_ABBREVIATIONS[abbreviation.to_sym] ||
    QUALITY_ABBREVIATIONS[abbreviation.upcase.to_sym] ||
    QUALITY_ABBREVIATIONS[abbreviation.downcase.to_sym]
end

#quality_name ⇒ Object 



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# File 'lib/head_music/diatonic_interval.rb', line 58

def quality_name
  words[0..-2].join(" ").to_sym
end

#steps ⇒ Object 



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# File 'lib/head_music/diatonic_interval.rb', line 66

def steps
  NUMBER_NAMES.index(degree_name)
end

#words ⇒ Object 



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# File 'lib/head_music/diatonic_interval.rb', line 54

def words
  identifier.to_s.split(/[_ ]+/)
end