Re: \override multiple properties?

[Aaron Hill]

On 2020-02-01 6:46 pm, Bric wrote:
> In my case i am needing to override a series of notes and then revert.
>  (So, don't want to use "\once"). I have already used your construct,
> coupling it with reverting directives grouped the same way (with a
> named group):
>
> emphasizeStem = {
>    \override Stem.thickness = #3.0
>    \override Stem.color = #'(0.5 0.3 0.2)
> }
>
> revertStem = {
>   \revert Stem.thickness
>   \revert Stem.color
> }

The \undo command can be useful to avoid needing to individually 
\revert:

%%%%
{ d'8 \emphasizeStem d' e' f' \undo \emphasizeStem g'4 d' }
%%%%


> What would be nice is be able to parametrize those blocks somehow
>
> But, i guess, that can only be done with a Scheme function? I'm shaky 
> on scheme.

Music functions certainly give you the most flexibility, although there 
are simple cases where you can use 2.19's \etc keyword as a shorthand to 
defining the function yourself:

%%%%
\version "2.19"

stemColor = \override Stem.color = \etc

{ d'8 \stemColor #red e' f' \undo \stemColor ##f g' }
%%%%

Note the \undo command above is less ideal as one needs to provide a 
dummy argument to the function.

Here would be one way to parameterize \emphasizeStem:

%%%%
\version "2.19"

emphasizeStem = #(define-music-function
  (thickness color)
  ((number? 3) color?)
  #{ \override Stem.thickness = #thickness
     \override Stem.color = #color #})

{ \emphasizeStem #red d'8 e'4
  \emphasizeStem 6 #blue f'2 }
%%%%

The above demonstrates how the first argument could be made optional.


-- Aaron Hill