%% http://lsr.di.unimi.it/LSR/Item?id=838

%LSR completed by P.P.Schneider on Feb. 2014 for v2.18

% These two lines are needed to force LilyPond to break only when
% YOU tell it to, via \break and \page Break. You may not need the page-break one.

%\layout {
%  \override Score.NonMusicalPaperColumn.line-break-permission = ##f
%  \override Score.NonMusicalPaperColumn.page-break-permission = ##f
%}

#(define ((bars-per-line-engraver bar-list) context)
  (let* ((working-copy bar-list)
         (total (1+ (car working-copy))))
    `((acknowledgers
       (paper-column-interface
        . ,(lambda (engraver grob source-engraver)
             (let ((internal-bar (ly:context-property context 'internalBarNumber)))
               (if (and (pair? working-copy)
                        (= (remainder internal-bar total) 0)
                        (eq? #t (ly:grob-property grob 'non-musical)))
                   (begin
                     (set! (ly:grob-property grob 'line-break-permission) 'force)
                     (if (null? (cdr working-copy))
                         (set! working-copy bar-list)
                         (begin
                           (set! working-copy (cdr working-copy))))
                           (set! total (+ total (car working-copy))))))))))))
						   
						   

% place inside a layout context like so:
%\score {
%  \layout {
%    \context {
%      \Score
%      %use the line below to insist on your layout
%      %\override NonMusicalPaperColumn.line-break-permission = ##f
%      \consists #(bars-per-line-engraver '(4))
%    }
%  }
%}