Class: HeadMusic::ChromaticInterval

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/head_music/chromatic_interval.rb

Overview

A chromatic interval is the distance between two pitches measured in half-steps.

Constant Summary collapse

NAMES =

TODO: include the Named module

%w[
  perfect_unison minor_second major_second minor_third major_third perfect_fourth tritone perfect_fifth
  minor_sixth major_sixth minor_seventh major_seventh perfect_octave
].freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(semitones) ⇒ ChromaticInterval

Returns a new instance of ChromaticInterval.



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# File 'lib/head_music/chromatic_interval.rb', line 24

def initialize(semitones)
  @semitones = semitones
end

Instance Attribute Details

#semitones ⇒ Object (readonly) Also known as: specific_interval

Returns the value of attribute semitones.



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# File 'lib/head_music/chromatic_interval.rb', line 15

def semitones
  @semitones
end

Class Method Details

.get(identifier) ⇒ Object 



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# File 'lib/head_music/chromatic_interval.rb', line 17

def self.get(identifier)
  @intervals ||= {}
  candidate = identifier.to_s.downcase.gsub(/\W+/, "_")
  semitones = NAMES.index(candidate) || identifier.to_i
  @intervals[semitones] ||= new(semitones.to_i)
end

Instance Method Details

#+(other) ⇒ Object 



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# File 'lib/head_music/chromatic_interval.rb', line 51

def +(other)
  HeadMusic::ChromaticInterval.get(to_i + other.to_i)
end

#-(other) ⇒ Object 



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# File 'lib/head_music/chromatic_interval.rb', line 55

def -(other)
  HeadMusic::ChromaticInterval.get((to_i - other.to_i).abs)
end

#<=>(other) ⇒ Object 



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# File 'lib/head_music/chromatic_interval.rb', line 59

def <=>(other)
  to_i <=> other.to_i
end

#compound? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/head_music/chromatic_interval.rb', line 36

def compound?
  semitones > 12
end

#diatonic_name ⇒ Object 



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# File 'lib/head_music/chromatic_interval.rb', line 44

def diatonic_name
  NAMES[simple.semitones].tr("_", " ")
end

#simple ⇒ Object 



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# File 'lib/head_music/chromatic_interval.rb', line 28

def simple
  HeadMusic::ChromaticInterval.get(semitones % 12)
end

#simple? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/head_music/chromatic_interval.rb', line 32

def simple?
  (0..12).cover?(semitones)
end

#to_i ⇒ Object 



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# File 'lib/head_music/chromatic_interval.rb', line 40

def to_i
  semitones
end