Displaying bar numbers only when point-and-click is enabled

Bar numbers are useful for editing, but for some types of music (such as hymns) should normally be removed completely. To make editing easier without requiring extra file modifications at production-time, this small Scheme function changes bar number visibility based on the point-and-click LilyPond option. When point-and-click is enabled, bar numbers are printed for every bar, but they have zero extent so that they are "invisible" to the layout engine; while this is ugly (remember, this is for score-debugging only), it should result in the development and production scores having identical spacing.

\version "2.24.0"

%% http://lsr.di.unimi.it/LSR/Item?id=863

% uncomment the follwong line 
%\pointAndClickOff

initBarNumberVisibility =
  #(define-music-function
    ()
    ()
    (if (ly:get-option 'point-and-click)
        #{
          \override Score.BarNumber.break-visibility = #'#(#t #t #t)
          % The following line makes bar numbers "invisible" to the collision-avoidance engine,
          % so that the preview & production scores should have identical spacing.
          \override Score.BarNumber.X-extent = #'(0 . 0)
        #}
        #{
          \override Score.BarNumber.break-visibility = #'#(#f #f #f)
        #})
    )
  
\score {
  \new Staff \relative c' {
    %\initBarNumberVisibility % Can be moved to the \layout block with later LilyPond versions
    \time 4/4
    c1*5 \break |
    c1*5 \break |
    c1*5 \bar "|." |
  }
  \layout {
    \context {
      \Score
      % I prefer this here, but it doesn't work in 2.14.2 (works in later versions, such as 2.16.1)
      \initBarNumberVisibility
    }
  }
}