Ottava alta (8va) and ottave bassa (8vb)

[Heikki Johannes Junes]

It would be nicer to input ottavas with lesser syntax. Consider the
following:

  \score { \notes \transpose c' c' {
        c'4
        \property Voice.TextSpanner \set #'type = #'dashed-line
        \property Voice.TextSpanner \set #'edge-height = #'(0 . 1.5)
        \property Voice.TextSpanner \set #'edge-text = #'("8va " . "")
        \property Staff.centralCPosition = #-13
        c''''4 #(ly:export (make-span-event 'TextSpanEvent START))
        s4*0#(ly:export (make-span-event 'TextSpanEvent STOP))
  } }

It prints c'4 note and c''''4 with ottava alta (8va, an octave higher).
It could be represented shorter:

  \score { \notes \transpose c' c' {
     c'4
     \startOttavaAlta c''''4 \stopOttavaAlta
  } }

Correspondingly ottave bassa (8vb, an octave lower), could be put as:


  \score { \notes \transpose c' c' {
     c'4
     \startOttaveBassa c''''4 \stopOttaveBassa
  } }

This would be very useful option. It is not so critical what is the
default line style of the invoked identifiers.

Greetings,

Heikki Junes