Re:

[ghe]

Thank you again, Thomas!

> Well, you could do the following, although it might be not be the same 
> as \hfill in Tex.

Indeed, there are a few differences, notably in the fact that the amount 
of space is not calculated automatically, and in the fact that it cannot 
be inserted between two elements (for example to put the final bar at the 
end of the staff instead of shortening the staff).  But, as I said, it is 
already a good solution, and I think I will live with it.

> \version "2.14.2"
>
> spaceRight =
> #(define-music-function (parser location space)(number?)
>  (let* ((amount (+ space 0.5))
>         (space-right `(extra-space . ,amount)))
>  #{
>     %% Maybe additional layout-objects must be affected!?
>     \once \override Score.BarLine #'space-alist #'right-edge = #`(extra-space . 
> ,$space)
>     \once \override Score.KeySignature #'space-alist #'right-edge = $space-right
>     \once \override Score.KeyCancellation #'space-alist #'right-edge = 
> $space-right
>     \once \override Score.TimeSignature #'space-alist #'right-edge = 
> $space-right
>  #}))
>
>
> hfill = \spaceRight #20
>
> {
>   %\spaceRight #30
>   %\key d\major
>   a4\( b c d~(
>   %\breathe
>   \hfill\break
>   %\time 8/8
>   %\clef alto
>   %\key cis\major
>   d4 b) c\) d \bar "|."
>   \hfill
> }

I see, I guess that the \once is there to prevent that the \spaceRight 
takes effect on all the staffs, which is indeed better.  (But I don't 
understand why \override BarLine had to be changed.)

--ghe