Module: HeadMusic::Notation::PreflightChecks

Included in:
ABC::Writer, LilyPond::Preflight, MusicXML::Preflight
Defined in:
lib/head_music/notation/preflight_checks.rb

Overview

Whole-composition checks shared by the notation writers’ preflights. Each check raises before any output is assembled, so a caller that passes them all can serialize without failing on these grounds; each includer supplies its own format-specific RenderError subclass through #render_error_class.

Instance Method Summary collapse

Instance Method Details

#ensure_contiguous_voices(composition) ⇒ Object (private) 



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# File 'lib/head_music/notation/preflight_checks.rb', line 11

def ensure_contiguous_voices(composition)
  composition.voices.each do |voice|
    gap = voice.first_gap
    raise_gap_error(voice, *gap) if gap
  end
end

#ensure_notes_within_barlines(composition) ⇒ Object (private) 



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# File 'lib/head_music/notation/preflight_checks.rb', line 18

def ensure_notes_within_barlines(composition)
  composition.voices.each do |voice|
    voice.placements.each do |placement|
      next unless placement.next_position > placement.position.start_of_next_bar

      raise render_error_class, "the note at #{placement.position} crosses its barline; " \
        "splitting notes across barlines is not supported"
    end
  end
end

#raise_gap_error(voice, expected_position, found_placement) ⇒ Object (private)

Raises:

  • (render_error_class) 


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# File 'lib/head_music/notation/preflight_checks.rb', line 29

def raise_gap_error(voice, expected_position, found_placement)
  if found_placement.equal?(voice.placements.first)
    raise render_error_class, "the first placement must start its bar " \
      "(found #{found_placement.position}); insert explicit rests to fill the gap"
  end

  raise render_error_class, "expected a placement at #{expected_position}, " \
    "found one at #{found_placement.position}; insert explicit rests to fill gaps"
end