grammar ABC::Grammar
{
regex basenote { <[a..g]+[A..G]> }
regex octave { "'"+ | ","+ }
regex accidental { '^' | '^^' | '_' | '__' | '=' }
regex pitch { <accidental>? <basenote> <octave>? }
regex number { <digit>+ }
regex note_length_denominator { '/' <bottom=number>? }
regex note_length { <top=number>? <note_length_denominator>? }
regex note { <pitch> <note_length> }
}