%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% %%%%%%%  Cut here ----- Start 'bbarred.ly'

%% C with slash -------------------------------
cWithSlash = \markup {
  \combine \roman C \translate #'(0.65 . -0.25) \draw-line #'(0 . 1.8)
}
%% Span -----------------------------------
%% Syntax: \bbarre #"text" { notes } - text = any fret number
bbarre= #(define-music-function (barre location str music) (string? ly:music?)
   (let ((elts (extract-named-music music '(NoteEvent EventChord RestEvent MultiMeasureRestMusic SkipEvent))))
     (if (pair? elts)
         (let ((first-element (first elts))
               (last-element (last elts)))
           (set! (ly:music-property first-element 'articulations)
                 (cons (make-music 'TextSpanEvent 'span-direction -1)
                       (ly:music-property first-element 'articulations)))
           (set! (ly:music-property last-element 'articulations)
                 (cons (make-music 'TextSpanEvent 'span-direction 1)
                       (ly:music-property last-element 'articulations))))))
   #{
       \once \override TextSpanner.font-size = #-2
       \once \override TextSpanner.font-shape = #'upright
       \once \override TextSpanner.staff-padding = #3
       \once \override TextSpanner.style = #'line
       \once \override TextSpanner.to-barline = ##f
       \once \override TextSpanner.bound-details =
            #`((left
                (text . ,#{ \markup \concat { \cWithSlash \hspace #.2 $str \hspace #.3 } #})
                (Y . 0)
                (padding . 0.25)
                (attach-dir . -2))
               (right
                (text . ,#{ \markup { \draw-line #'(0 . -.5) } #})
                (Y . 0)
                (padding . 0.25)
                (attach-dir . 2)))
       \once \override TextSpanner.bound-details.left-broken.attach-dir = #-1
%%%%%% comment or delete those two lines for showing left-broken barred fret number :
       \once \override TextSpanner.bound-details.left-broken.text = ##f
       \once \override TextSpanner.bound-details.right-broken.text = ##f       
%% uncomment this line for make full barred       
       %\once  \override TextSpanner.bound-details.left.text =  \markup \concat { \roman B \hspace#.2 $str \hspace #.3 }                        
       $music
   #})

%% %%%%%%%  Cut here ----- End 'bbarred.ly'
%% Copy and change the last line for full barred. Rename in 'fbarred.ly'
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% this comment will be deleted :
\markup\italic "Here's a half barré example that could replace the one in the doc :"

{ 
  \clef "G_8" 
  \key d\minor
  << 
    {
      \stemUp 
      \bbarre #"III" { a'16[  bes d' bes f'8] } 
    } 
    \\ 
    {
      \stemDown d2
    } 
  >>
}

%% Not part of the snippet           
%% those are just here to illustrate 
\markup\italic "Here are some other examples (won't be in the snippet) :"

{ 
  \clef "G_8" 
  \stemUp \bbarre #"III" { 
    \compressFullBarRests
    R1*5 R 
  } 
}

{ 
  \clef "G_8" 
  \stemUp \bbarre #"III" { R1*5 R } 
}

{ 
  \clef "G_8" 
  \stemUp \bbarre #"III" { r1*5 r } 
}

{ 
  \clef "G_8" 
  \stemUp \bbarre #"III" { s1*5 \break s } 
}