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Contents
# frozen_string_literal: true
# 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.
class HeadMusic::Register
include Comparable
DEFAULT = 4
def self.get(identifier)
from_number(identifier) || from_name(identifier) || default
end
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
def self.from_name(string)
return unless string.to_s.match?(HeadMusic::Spelling::MATCHER)
_letter, _sign, register_string = string.to_s.match(HeadMusic::Spelling::MATCHER).captures
@registers ||= {}
@registers[register_string.to_i] ||= new(register_string.to_i) if register_string
end
def self.default
@registers[DEFAULT] ||= new(DEFAULT)
end
attr_reader :number
delegate :to_i, :to_s, to: :number
def initialize(number)
@number = number
end
def <=>(other)
to_i <=> other.to_i
end
def +(other)
self.class.get(to_i + other.to_i)
end
def -(other)
self.class.get(to_i - other.to_i)
end
def helmholtz_case
return :upper if number < 3
:lower
end
def helmholtz_marks
return "," * (2 - number) if number < 2
return "'" * (number - 3) if number > 3
""
end
private_class_method :new
end
Version data entries
9 entries across 9 versions & 1 rubygems