Re: Alternating time signatures

[David Kastrup]

Urs Liska <address@hidden> writes:

> Hi,
>
> in my current examination of polymetrics I stumbled over a missing
> item in LilyPond: alternating time signatures.
>
> In contemporary notation (well, actually starting quite early in the
> 20th century, so "contemporary" isn't really adequate) it's a common
> concept to write sth like
>
> 6 5
> 8 8
>
> to indicate a section with (irregularly) changing meters.
>
> This can easily be achieved by overriding the TimeSignature stencil,
> but as far as I can tell there is no suitable documentation for this.

Huh.  You can do

{
  \once\override Staff.TimeSignature.stencil =
  #(lambda (grob)
    (grob-interpret-markup grob
     #{ \markup \number \override #'(baseline-skip . 0)
     { \column { 6 8 } \column { 5 8 } } #}))
  \time 6/8
  \cadenzaOn
  c1
}

but that's sort of cumbersome.

> There _had_ been a snippet to achieve
>
> 6   5
>   +
> 8   8
>
> which is a different thing but could easily be adapted.

Maybe one should provide more control over the formatting here.  Like
being able to specify the separating markup (hardwired to "+").

> b)
> Create a new command for LilyPond itself, as a complement to
> \compoundTimeSignature and write appropriate documentation.
>
> I prefer solution b) but will only create a patch if I can expect not
> to get objections about the usefulness in itself.

Problem is that this is then again a special case.  Probably makes sense
only with unmetered music.  I'm currently working on some preliminary
patch that makes \bar "anything-but-an-empty-string" advance the bar
counter in unmetered music in order to get sane semantics for
accidentals, bar numbers and so on.  But it's not working properly yet.

You would probably need something like that anyway (LSR333 does no
longer work).

-- 
David Kastrup