Re: Changing context plugins

[Thomas Morley]

2016-12-05 16:29 GMT+01:00 David Sumbler <address@hidden>:

> But two questions have occurred to me arising out of this.
>
> 1) Plug-ins for most contexts can be added or removed either in a
> \layout block, as above, or when creating the context, e.g.
>
> \new \Staff \with { consists Mark_engraver }

This is invalid syntax, you probably meant:
\new Staff \with { \consists Mark_engraver }

>
> But this second method can't, so far as I can see, be used with a Score
> context, because '\new \Score' is not allowed.  Can Score plug-ins only
> be added or removed within a \layout block?

'\new \Score' is invalid syntax as well, but

\new Score \with { \remove "Mark_engraver" }
<<
\new Staff
  \relative c'' { c4 \mark \default s c2 }
\new Staff \with { \consists "Mark_engraver" }
  \relative c'' { c4 s \mark \default c2 }
>>

works fine. Though, it could easily be written like:

\score {
  <<
  \new Staff
    \relative c'' { c4 \mark \default s c2 }
  \new Staff \with { \consists "Mark_engraver" }
    \relative c'' { c4 s \mark \default c2 }
  >>
  \layout {
    \context {
      \Score
      \remove "Mark_engraver"
    }
  }
}

I vagely remember discussions about the topic years ago. Everyone
agreed, so the possibility to write
\new Score \with ...
is not mentioned anywhere at all, but still valid syntax.

>
> 2) More importantly, is it possible to change these settings at an
> arbitrary point in the music, i.e. after the context has been created?

Nope, not for the engravers being in the context or not.
You have to go for properties of context/grob/whatever read/written by
the relevant engravers.

Cheers,
 Harm