Re: \applyContext, StaffSymbol, and \stopStaff \startStaff

[Paul Morris]

> On Oct 19, 2015, at 1:56 AM, David Kastrup <address@hidden> wrote:
> 
> I think your main problem is that you are using \applyContext here at
> Voice level where it does not really do anything worthwhile.

Ah, I see.

> Try \context Staff \applyContext …

That did the trick and now it works, thanks!

\version “2.19.22” 

myfunc =
#(define-music-function () ()
   #{
     \context Staff
     \applyContext
     #(lambda (context)
        ;; access context properties and pick a property setting based on 
them...
        (ly:context-pushpop-property context 'StaffSymbol 'color green))
     \stopStaff
     \startStaff
   #})

{
  c'
  % now it works!
  \context Staff
  \applyContext
  #(lambda (context)
     ;; access context properties and pick a property setting based on them...
     (ly:context-pushpop-property context 'StaffSymbol 'color red))  
  \stopStaff \startStaff
  c'
  % and you can put it in a music function
  \myfunc
  c'
}


> Though frankly I have no idea what \myFunc is trying to do.  You are
> keeping state in a global variable which is not going to work when using
> \myFunc in several contexts in parallel.

Um, never mind that, it was just my clumsy attempt to try to use \override 
Staff.StaffSymbol... to set the grob property when I couldn’t get 
ly:context-pushpop-property to work.  

Thanks again, I really appreciate your help.  No telling how long or if I would 
have ever figured that out on my own.

-Paul