I have gotten around my issue by changing from using \relative to using
\fixed. See below. In the sample below.
In the sample below I took \parenthesize out of the picture to isolate
it from the issue I was having.
So to recap.
* My original goal was to have () around certain notes in the score
that only show up if the music is being printed for a specific
instrument.
* I tried other ways to only have \parenthesize used for a given
instrument but it seemed the only clean way to do it in a general
way was using tags in a function.
* But doing seemed to introduce an issue with \relative notes.
Changing to \fixed notes seems to have resolved that.
* Using \fixed is reasonable for the song I'm working on.
* But that leaves the mystery for a later date about using relative
with tags in a function. I have experimented with
\resetRelativeOctave but that seems a bit cumbersome.
code:
\version "2.26.0"
\language "english"
par = #(define-music-function (note) (ly:music?)
#{
\tag #'(guitar) { $note }
\tag #'(piano) { $note }
#})
musicRel = \relative c' {cs1 \par cs' |}
\score {
{
\keepWithTag #'piano {\musicRel}
}
}
\score {
{
\keepWithTag #'guitar {\musicRel}
}
}
\void \displayLilyMusic \keepWithTag #'piano {\musicRel}
\void \displayLilyMusic \keepWithTag #'guitar {\musicRel}
musicFix = \fixed c' {cs1 \par cs' |}
\score {
{
\keepWithTag #'piano {\musicFix}
}
}
\score {
{
\keepWithTag #'guitar {\musicFix}
}
}
\void \displayLilyMusic \keepWithTag #'piano {\musicFix}
\void \displayLilyMusic \keepWithTag #'guitar {\musicFix}
log result:
{ \absolute { cs'1 { \tag #'piano { cs'''1 } } |
} }
{ \absolute { cs'1 { \tag #'guitar { cs''1 } } |
} }
{ \absolute { cs'1 { \tag #'piano { cs''1 } } |
} }
{ \absolute { cs'1 { \tag #'guitar { cs''1 } } |
} }
