Class: HeadMusic::Rudiment::Register

Inherits:
Base
  • Object
show all
Includes:
Comparable
Defined in:
lib/head_music/rudiment/register.rb

Overview

The register is a numeric octave identifier used in scientific pitch notation.

A pitch is a spelling plus a register. For example, C4 is middle C and C5 is the C one octave higher. The number changes between the letter names B and C regardless of sharps and flats, so as an extreme example, Cb5 is actually a semitone below B#4.

Constant Summary collapse

AUDIBLE_REGISTERS = 
(0..10).map.freeze
PATTERN = 
Regexp.union(AUDIBLE_REGISTERS.map(&:to_s))
DEFAULT = 
4

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(number) ⇒ Register

Returns a new instance of Register.



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# File 'lib/head_music/rudiment/register.rb', line 45

def initialize(number)
  @number = number
end

Instance Attribute Details

#number ⇒ Object (readonly)

Returns the value of attribute number.



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# File 'lib/head_music/rudiment/register.rb', line 41

def number
  @number
end

Class Method Details

.default ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 37

def self.default
  @registers[DEFAULT] ||= new(DEFAULT)
end

.from_name(string) ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 29

def self.from_name(string)
  return unless string.to_s.match?(HeadMusic::Rudiment::Spelling::MATCHER)

  _letter, _sign, register_string = string.to_s.match(HeadMusic::Rudiment::Spelling::MATCHER).captures
  @registers ||= {}
  @registers[register_string.to_i] ||= new(register_string.to_i) if register_string
end

.from_number(identifier) ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 21

def self.from_number(identifier)
  return nil unless identifier.to_s == identifier.to_i.to_s
  return nil unless (-2..12).cover?(identifier.to_i)

  @registers ||= {}
  @registers[identifier.to_i] ||= new(identifier.to_i)
end

.get(identifier) ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 17

def self.get(identifier)
  from_number(identifier) || from_name(identifier) || default
end

Instance Method Details

#+(other) ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 53

def +(other)
  self.class.get(to_i + other.to_i)
end

#-(other) ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 57

def -(other)
  self.class.get(to_i - other.to_i)
end

#<=>(other) ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 49

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

#helmholtz_case ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 61

def helmholtz_case
  return :upper if number < 3

  :lower
end

#helmholtz_marks ⇒ Object 



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# File 'lib/head_music/rudiment/register.rb', line 67

def helmholtz_marks
  return "," * (2 - number) if number < 2
  return "'" * (number - 3) if number > 3

  ""
end