Class: HeadMusic::Style::Guides::ContourMelody

Inherits:
SpeciesMelody show all
Defined in:
lib/head_music/style/guides/contour_melody.rb

Overview

A free diatonic melody targeting a specific contour. Configured rather than subclassed: ContourMelody.with(contour: :arch, minimum_melodic_intervals: 2).

Deliberately not a subclass of DiatonicMelody, whose lists are reached fully-qualified below, so nothing is inherited by accident.

Class Method Summary collapse

Class Method Details

.assess(voice) ⇒ Object

Guide.get passes through anything that assesses a voice, so naming this class instead of a registry key would otherwise fail with a bare “missing keyword: :contour”. Both seams raise, so the message arrives either way.

Raises:

  • (ArgumentError) 


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# File 'lib/head_music/style/guides/contour_melody.rb', line 22

def self.assess(voice) = raise(ArgumentError, unconfigured_message)

.assess_items(voice) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/head_music/style/guides/contour_melody.rb', line 24

def self.assess_items(voice) = raise(ArgumentError, unconfigured_message)

.items_by_tier(contour:, minimum_melodic_intervals: nil) ⇒ Object

The keyword signature is the declaration, and its arity is what .with checks to decide the guide is configurable. Everything DiatonicMelody teaches is background here; the contour is the lesson.



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# File 'lib/head_music/style/guides/contour_melody.rb', line 35

def self.items_by_tier(contour:, minimum_melodic_intervals: nil)
  motion_gate =
    minimum_melodic_intervals &&
    HeadMusic::Style::Guidelines::MinimumMelodicIntervals.with(minimum_melodic_intervals)

  normalize(
    gate: [*HeadMusic::Style::Guides::DiatonicMelody.gate_items, motion_gate],
    primary: [HeadMusic::Style::Guidelines::Contoured.with(contour)],
    secondary: HeadMusic::Style::Guides::DiatonicMelody.primary_items
  )
end

.unconfigured_message ⇒ Object 



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# File 'lib/head_music/style/guides/contour_melody.rb', line 26

def self.unconfigured_message
  "#{name} requires configuration. " \
    "Use #{name}.with(contour: :arch, minimum_melodic_intervals: 2) " \
    'or HeadMusic::Style::Guide.get("arch_contour_melody").'
end

.with(contour:, minimum_melodic_intervals: nil) ⇒ Object

Eager, so an invalid contour raises at configuration time rather than at analysis. Required keyword, so a misspelled option name raises too.



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# File 'lib/head_music/style/guides/contour_melody.rb', line 12

def self.with(contour:, minimum_melodic_intervals: nil)
  super(
    contour: HeadMusic::Style::Guidelines::Contoured.normalized_contour(contour),
    minimum_melodic_intervals: minimum_melodic_intervals
  )
end