Re: Should \partial accept music instead of duration?

[Aaron Hill]

On 2022-03-19 5:46 pm, Thomas Morley wrote:
Am So., 20. März 2022 um 00:02 Uhr schrieb Aaron Hill
<lilyp...@hillvisions.com>:

Here would be a possible refactoring:

%%%%
\version "2.22.0"

partial =
#(define-music-function (mus) (ly:music?)
   (_i "Make a partial measure.")
   (let* ((mom (ly:music-length mus))
          (dur (make-duration-of-length mom)))
     (make-music 'SequentialMusic
       'elements
       (list (context-spec-music
               (make-music 'PartialSet
                           'origin (*location*)
                           'duration dur)
               'Timing)
         mus))))


\fixed c' {
   \time 3/4
   \partial { g8 a4 }
   | g2. \bar "||"
   \partial { \grace { g16 } a8 b }
   | a2. \bar "||"
   \partial \tuplet 3/2 { g8 fis }
   | g2. \bar "|."
}
%%%%

A convert-ly rule would probably not be possible given the limited 
power
of regular expressions.  As such, \partial might need to support both
duration and music arguments.  Initially I thought this might not be
possible, given that a naked duration can be treated as music; but the
following does seem to work:

%%%%
\version "2.22.0"

#(define (duration-or-music? arg)
   (or (ly:duration? arg) (ly:music? arg)))

partial =
#(define-music-function (arg) (duration-or-music?)
   (_i "Make a partial measure.")
   (if (ly:duration? arg)
     (context-spec-music
       (make-music 'PartialSet
                   'origin (*location*)
                   'duration arg)
       'Timing)
     (let* ((mom (ly:music-length arg))
            (dur (make-duration-of-length mom)))
       (make-music 'SequentialMusic
         'elements
         (list (context-spec-music
                 (make-music 'PartialSet
                             'origin (*location*)
                             'duration dur)
                 'Timing)
           arg)))))


\fixed c' {
   \time 3/4
   \partial 4. g8 a4 %% Original syntax works.
   | g2. \bar "||"
   \partial { \grace { g16 } a8 b }
   | a2. \bar "||"
   \partial \tuplet 3/2 { g8 fis }
   | g2. \bar "|."
}
%%%%


-- Aaron Hill

Hi Aaron,

I really like it! Always wondered why we need to specify a duration,
if it can be taken from the music.
I'd suggest to propose it on devel. Preferable the second coding,
because we could nicely deprecate the old syntax for some versions.

*facepalm*  I thought I was sending to devel.  Well, folks on user might 
want to chime in too.


-- Aaron Hill