Re: How to generate \scaleDurations values procedurally

[Lib Lists]

On Mon, 12 Jun 2023 at 00:08, Jean Abou Samra <jean@abou-samra.fr> wrote:
>
> Le dimanche 11 juin 2023 à 23:55 +0200, Lib Lists a écrit :
>
> Hello, I'm (re)working on a series of pieces for player piano. I'd like to 
> find a way to generate all the \scaleDurations values so that I don't have to 
> type them by hand. In the example below they follow a simple pattern (60/60k 
> 60/59, 60/58, etc.). Unfortunately my knowledge of Scheme is very limited. 
> Moreover, I wouldn't know how to insert the generated values to the right 
> staves. Any hint would be really appreciated!
>
> Like this?
>
> \version "2.25.5"
>
> mus = \repeat unfold 3 { c c c c }
>
>
> \score {
>   \new StaffGroup  <<
>     #@(map (lambda (i)
>              #{ \new Staff { \scaleDurations #(cons 60 i) \mus } #})
>            (iota 10 60 -1))
>   >>
>
>    \layout {
>     \enablePolymeter
>     \context {
>       \Score
>       \override SpacingSpanner.base-shortest-duration = #(ly:make-moment 1/4)
>       proportionalNotationDuration = #(ly:make-moment 1/10)
>       \override SpacingSpanner.uniform-stretching = ##t
>       \override SpacingSpanner.strict-note-spacing = ##t
>       \remove "Timing_translator"
>       forbidBreakBetweenBarLines = ##f
>     }
>
>     \context {
>       \Staff
>       \remove "Time_signature_engraver"
>       \override BarLine.stencil = ##f
>       \override BarLine.allow-span-bar = ##f
>     }
>
>     \context {
>       \Voice
>       \remove Forbid_line_break_engraver
>     }
>   }
> }
>
> The 60/59 notation is just LilyPond syntax for the Scheme pair (60 . 59).
>
> There is some info about #@ here (and if you didn't know about pairs, you can 
> read this).
>
> Best,
>
> Jean

Hi Jean,
thank you so much, that works perfectly! And thank you also for the resources.
If I may still ask for some help, I now tried to transpose the pitches
so that the first staff has 'c', the second staff 'b', and so on. In
other words, each staff's pitch is one semitone lower than the
previous (or other transposition interval). I tried to add the
transpose function but got stuck.

In your example, I changed the line:
#{ \new Staff { \scaleDurations #(cons 60 i) \mus } #})

to this:
#{ \new Staff { \scaleDurations #(cons 60 i)  #(ly:music-transpose
{\mus} i)  } #})

but clearly there's something wrong,

Thank you and
best regards,

Lib