%%
%% Notating unmetered music with Lilypond. 
%%
%% The code below takes care of proper accidental notation and
%% incrementing bar numbers for manually inserted barlines at
%% arbitrary places
%%
%% From Lily snippets (http://lsr.dsi.unimi.it/LSR/Item?id=333)
%%

%%
%% Usage: 
%%
%% Include this file in Lilypond header. Set \cadenzaOn for
%% score. Manually enter barlines with \ibar (standard bar) or \nibar
%% <bar-string> (for special bars, e.g., \nibar "|.").
%%

\layout {
\context {
\Staff \remove Time_signature_engraver
}
} 

increaseBarNumber = \applyContext
#(lambda (x)
  (let ((measurepos (ly:context-property x 'measurePosition)))
   ; Only increase bar number if not at start of measure.
   ; This way we ensure that you won't increase bar number twice
   ; if two parallel voices call increaseBarNumber simultanously:
   (if (< 0 (ly:moment-main-numerator measurepos)) ; ugh. ignore grace part
    (begin
     (ly:context-set-property!
      (ly:context-property-where-defined x 'internalBarNumber)
      'internalBarNumber
      (1+ (ly:context-property x 'internalBarNumber)))
     (ly:context-set-property!
      (ly:context-property-where-defined x 'currentBarNumber)
      'currentBarNumber
      (1+ (ly:context-property x 'currentBarNumber)))
     ; set main part of measurepos to zero, leave grace part as it is:
     (ly:context-set-property!
      (ly:context-property-where-defined x 'measurePosition)
      'measurePosition
      (ly:make-moment 0 1
       (ly:moment-grace-numerator measurepos)
       (ly:moment-grace-denominator measurepos)))))))

% Named Increasing BAR
nibar = #(define-music-function (parser location x) (string?)
#{
  \bar $x
  \increaseBarNumber
#})

% Increasing BAR
ibar = \nibar "|"