Re: Feature request: let \layout accept several \layouts stored in variables

[Urs Liska]

Am 15.07.2018 um 17:36 schrieb Simon Albrecht:
> On 15.07.2018 16:48, David Kastrup wrote:
> > What?  Being able to specify two conflicting \layout definitions at once
> > and having LilyPond magically merge them by guessing correctly how the
> > user wants every conflict to be resolved?
> >
> > Magic is always a great thing to wish for.  Until it does stuff you
> > actually did not intend it to do.
>
> That’s not what the request was about. Lily already merges subsequent 
> toplevel layout definitions, IIUC simply following the order at which 
> they are encountered, and why shouldn’t the same be possible inside 
> one layout block?
>
> This works just as expected:
>
> %%%%%%%%%%%%%%%%%%%%
> \version "2.19.82"
>
> \score {
>   { c'8 }
>   \layout {
>     \context {
>       \Voice
>       \override NoteHead.color = #red
>     }
>     \context {
>       \Voice
>       \omit Flag
>       \override NoteHead.color = #green
>     }
>   }
> }
> %%%%%%%%%%%%%%%%%%%%
>
> and IIUC the request asks for this
>
> %%%%%%%%%%%%%%%%%%%%
> \version "2.19.82"
>
> redhead = \layout {
>   \context {
>     \Voice
>     \override NoteHead.color = #red
>   }
> }
> greenhead = \layout {
>   \context {
>     \Voice
>     \omit Flag
>     \override NoteHead.color = #green
>   }
> }
> \score {
>   { c'8 }
>   \layout {
>     \redhead
>     \greenhead
>   }
> }
> %%%%%%%%%%%%%%%%
>
> to be treated exactly the same instead of discarding \greenhead.

I think it's more about something like

%%%%%%%%%%%%%%%%%%%%
\version "2.19.82"

redhead = \layout {
  \context {
    \Voice
    \override NoteHead.color = #red
  }
}
greenbeam = \layout {
  \context {
    \Voice
    \override Beam.color = #green
  }
}
\score {
  { c'8 }
  \layout {
    \redhead
    \greenbeam
  }
}
%%%%%%%%%%%%%%%%

to produce red note heads and green beams.