Hi Aaron,
Thanks for the quick and helpful response!
> Yes. The list-splicing forms of # and $ are #@ and $@, respectively.
Ah!
> In this case, we are using $@ to take the list of bare pitches and have the
> parser handle them the same as if the user had simply entered them.
Nice to know how that works.
> I have learned to never make assumptions on performance without concrete,
> profiling data.
A good philosophy.
> Mainly, I wanted to show you a different coding pattern just so you are aware
> of the options available.
Definitely appreciated!
> music-pitches extracts just the pitch information from the music. That means
> a lot of what makes up a music expression is lost in the process. For
> instance, chords will appear as individual pitches. Depending on your needs,
> this could be acceptable.
It was also a relatively gentle way in to Scheme-ing. ;)
> However, is it ultimately your intention to transform a music expression by
> altering the pitches according to some process (like a \modalTranspose)?
Yes.
> If so, extracting pitches is probably not the best approach. Instead, you
> will want to use music-map (or one of its kin) to help you traverse the music
> expression, so you can then conditionally modify each part as needed.
Very helpful! Here’s an example of what I’m currently playing around with:
%%%% SNIPPET BEGINS
\version "2.19.83"
\language "english"
rowrefs = #'(6 8 7 2 3 12 5 4 11 1 10 9)
test = { ef4. <fs' a'>8 g2 r4 <b d''>8 cs' }
xform-pitches =
#(define-music-function (music) (ly:music?)
(music-map
(lambda (elem)
(if (memq 'note-event (ly:music-property elem 'types))
(let* ((pitch (ly:music-property elem 'pitch))
(semitone (ly:pitch-semitones pitch))
(index (modulo semitone (length rowrefs))))
(ly:music-set-property! elem 'pitch
(ly:make-pitch 0 (list-ref rowrefs index) 0))))
elem)
music)
music)
\layout {
\context {
\Staff
\name RowReductionStaff
\alias Staff
\inherit-acceptability RowReductionStaff Staff
\omit Clef
\omit TimeSignature
\omit Stem
\omit Flag
\omit Beam
\omit Dots
\omit Rest
\omit BarLine
\override NoteHead.duration-log = #4
}
}
\score {
<<
{ \test }
\new RowReductionStaff { \xform-pitches \test }
>>
}
%%%% SNIPPET ENDS
Thanks for your help so far!
Cheers,
Kieren.
________________________________
Kieren MacMillan, composer (he/him/his)
‣ website: www.kierenmacmillan.info
‣ email: i...@kierenmacmillan.info
