Lilypond functions
Hello everyone,
Functions in Lilypond can also be written in pure Sheme syntax like this
#(define abcd
(lambda (x y ... )
PROCEDURE USING x y ...))
and then called within Lilypond with the syntax
\abcd x y ...
or within a Sheme fucntion with the syntax
(abcd x y ...)
If anyone is interested, I made an exercise for myself to explore *the use of
functions*
and create a score of the *first Prelude of Book I of J.S. Bach's Well-Tempered
Clavier*
As this piece has 32 bars using the same pattern based on 5 notes, plus an
ending in 3 bars,
I used a simple list of notes (without any rythmic indications) as my main data
and designed functions to extract the groups of 5 notes, apply the patterns to create
voices and scores, including a chord version on the piece in addition to the standard score.
notes = {
c e g c e
c d a' d f
b d g d' f ... etc.
)
Files (Lilypond, PDF and midi) are in this online folder
(midi files need to be downloaded to listen to them)
Silvain Dupertuis
Merci
This is a perfect solution, and, a clear explanation about why my solution
failed.
Thank you very much
Ken Ledeen
Mobile: 617-817-3183
www.nevo.com
www.bitsbook.com
tiny.cc/KenLedeen
tiny.cc/KenLedeenAmazon
ᐧ
On Sat, Feb 27, 2021 at 10:43 AM Jean Abou Samra > wrote:
Le 27/02/2021 à 02:16, Ken Ledeen a écrit :
> I am struggling to understand the restrictions on substitution functions.
>
> For example:
>
> 1) can a function include "\score { ...}" or can it only be invoked
> INSIDE a \score?
>
> 2) is it possible to include \header { ...} inside a substitution
> function? It fails when I try, but I don't understand why.
>
> I assume I am missing some basic concepts regarding their use.
>
> Thanks!
Hello,
Music functions must return music objects; \score blocks are not music
but general containers that enclose music as well as other objects such
as \header and \layout blocks.
However, replacing define-music-function with define-scheme-function,
you can define more versatile functions that are allowed to return any
kind of object for interpretation. For example:
\version "2.23.1"
failingFunction =
#(define-music-function () ()
#{
\score {
\header {
piece = "Piece A"
}
{ c' }
}
#})
% \failingFunction
succeedingFunction =
#(define-scheme-function () ()
#{
\score {
\header {
piece = "Piece B"
}
{ c' }
}
#})
\succeedingFunction
Hope that helps,
Jean
Re: How to get bounding NoteColumns of the first of consecutive TextSpanners
On Wed, Mar 3, 2021 at 3:17 PM David Nalesnik wrote:
>
> The only thing I can think of at the moment is to compare the
> StaffSymbol of the left bound with that of each of the NoteColumns on
> the right. Of course, I realize right away that that will break down
> if the spanner crosses a line break. (Use an override of
> 'before-line-breaking?)
>
> Here's the code I hacked up. I'll keep thinking about this.
>
> Best,
> David
>
> %%
>
> #(define tst
>(lambda (grob)
> (let* ((left-bound (ly:spanner-bound grob LEFT))
> (right-bound (ly:spanner-bound grob RIGHT))
> (ncs-from-grob
> (ly:grob-array->list (ly:grob-object grob 'note-columns)))
> (right-bound-elts
> (ly:grob-array->list
> (ly:grob-object right-bound 'elements)))
> (ncs-from-right-bound
> (filter
> (lambda (elt) (grob::has-interface elt 'note-column-interface))
> right-bound-elts))
> (left-bound-staff-symbol (ly:grob-object left-bound
> 'staff-symbol))
> (same-staff-right-bound-nc
> (filter
> (lambda (nc)
> (eq? (ly:grob-object nc 'staff-symbol)
> left-bound-staff-symbol))
> ncs-from-right-bound))
> )
>(ly:grob-set-property!
> (ly:grob-array-ref
> (ly:grob-object (car same-staff-right-bound-nc) 'note-heads)
> 0)
> 'color red)
>(pretty-print
> (list
> left-bound
> right-bound
> ncs-from-grob
> (equal? left-bound (car ncs-from-grob))
> ncs-from-right-bound
> same-staff-right-bound-nc
> )
>
> mus = {
> bes4-\tweak #'after-line-breaking #tst
> \startTextSpan
> b\stopTextSpan
> \startTextSpan
> bis\stopTextSpan
> }
>
> <<
> { a4 a a }
> \mus
> { c' c' c' }
> >>
Rather than comparing with the StaffSymbol of the left bound, it would
be better to look at the StaffSymbol of the TextSpanner:
#(define tst
(lambda (grob)
(let* ((left-bound (ly:spanner-bound grob LEFT))
(right-bound (ly:spanner-bound grob RIGHT))
(ncs-from-grob
(ly:grob-array->list (ly:grob-object grob 'note-columns)))
(right-bound-elts
(ly:grob-array->list
(ly:grob-object right-bound 'elements)))
(ncs-from-right-bound
(filter
(lambda (elt) (grob::has-interface elt 'note-column-interface))
right-bound-elts))
(spanner-staff-symbol (ly:grob-object grob 'staff-symbol))
(same-staff-right-nc
(filter
(lambda (nc)
(eq? (ly:grob-object nc 'staff-symbol)
spanner-staff-symbol))
ncs-from-right-bound))
)
(ly:grob-set-property!
(ly:grob-array-ref
(ly:grob-object (car same-staff-right-nc) 'note-heads)
0)
'color red)
(pretty-print
(list
left-bound
right-bound
ncs-from-grob
(equal? left-bound (car ncs-from-grob))
ncs-from-right-bound
same-staff-right-nc
)
mus = {
bes4-\tweak #'after-line-breaking #tst
\startTextSpan
b\stopTextSpan
\startTextSpan
bis\stopTextSpan
}
<<
{ a4 a a }
\mus
{ c' c' c' }
>>
%%%
HTH,
David
Re: How to get bounding NoteColumns of the first of consecutive TextSpanners
Le 03/03/2021 à 13:55, Thomas Morley a écrit :
Hi,
please have a look at the following minimal, producing three staves,
the middle one with consecutive TextSpanners:
mus = { bes \startTextSpan b\stopTextSpan \startTextSpan bis\stopTextSpan }
<< { a4 a a } \mus { c' c' c' } >>
Now I want to know the starting and ending NoteColumns of the _first_
TextSpanner.
Though, the first TextSpanner is left-bounded by NoteColumn and
right-bounded by PaperColumn.
How to get the NoteColumn at first TextSpanner's end?
Below some test-code.
Obviously I can filter PaperColumn's elements for NoteColumns, but
PaperColumn is a Score-grob, thus I get all three.
How to select?
(I may not know the position of the Staff with the TextSpanners)
#(define tst
(lambda (grob)
(let* ((left-bound (ly:spanner-bound grob LEFT))
(right-bound (ly:spanner-bound grob RIGHT))
(ncs-from-grob
(ly:grob-array->list (ly:grob-object grob 'note-columns)))
(right-bound-elts
(ly:grob-array->list
(ly:grob-object right-bound 'elements)))
(ncs-from-right-bound
(filter
(lambda (elt) (grob::has-interface elt 'note-column-interface))
right-bound-elts))
)
(pretty-print
(list
left-bound
right-bound
ncs-from-grob
(equal? left-bound (car ncs-from-grob))
ncs-from-right-bound
)
mus = {
bes4-\tweak #'after-line-breaking #tst
\startTextSpan
b\stopTextSpan
\startTextSpan
bis\stopTextSpan
}
<<
{ a4 a a }
\mus
{ c' c' c' }
Thanks,
Harm
Hi,
This looks tricky indeed.
Maybe an engraver operating in Voice context? Here's my attempt:
\version "2.23.1"
#(set-object-property! 'bounding-note-columns 'backend-type? pair?)
Set_bounding_note_columns_engraver =
#(lambda (context)
(let ((spanner-starting #f)
(spanner-ending #f)
(note-column #f))
(make-engraver
(acknowledgers
((line-spanner-interface engraver grob source-engraver)
(set! spanner-starting grob)
(ly:grob-set-property! grob
'bounding-note-columns
; Huh, '(#f . #f) makes a unique object?
(cons #f #f)))
((note-column-interface engraver grob source-engraver)
(set! note-column grob)))
(end-acknowledgers
((line-spanner-interface engraver grob source-engraver)
(set! spanner-ending grob)))
((stop-translation-timestep engraver)
(if spanner-starting
(set-car! (ly:grob-property spanner-starting
'bounding-note-columns)
note-column))
(if spanner-ending
(set-cdr! (ly:grob-property spanner-ending
'bounding-note-columns)
note-column))
(set! spanner-starting #f)
(set! spanner-ending #f)
(set! note-column #f)
% For testing
#(use-modules (srfi srfi-26))
#(define (visualize-note-column-bounds grob)
(let* ((cols (ly:grob-property grob 'bounding-note-columns))
(left-col (car cols))
(right-col (cdr cols))
(left-note-heads (ly:grob-array->list (ly:grob-object
left-col 'note-heads)))
(right-stem (ly:grob-object right-col 'stem)))
(for-each
(cute ly:grob-set-property! <> 'color red)
left-note-heads)
(ly:grob-set-property! right-stem 'color blue)))
\layout {
\context {
\Voice
\consists \Set_bounding_note_columns_engraver
\override TextSpanner.after-line-breaking =
#visualize-note-column-bounds
}
}
mus = {
bes4\startTextSpan
b\stopTextSpan
\startTextSpan
bis\stopTextSpan\startTextSpan
b\stopTextSpan
}
<<
{ a4 a a }
\mus
{ c' c' c' }
>>
Like David's solution, this of course won't give you the note columns
for each of the broken pieces. Well, I am in fact not sure that a notion
of the bounding note columns for a broken text spanner can even be
defined. Thoughts?
Cheers,
Jean
Re: How to get bounding NoteColumns of the first of consecutive TextSpanners
Hi Harm,
On Wed, Mar 3, 2021 at 6:56 AM Thomas Morley wrote:
>
> Hi,
>
> please have a look at the following minimal, producing three staves,
> the middle one with consecutive TextSpanners:
>
> mus = { bes \startTextSpan b\stopTextSpan \startTextSpan bis\stopTextSpan }
> << { a4 a a } \mus { c' c' c' } >>
>
> Now I want to know the starting and ending NoteColumns of the _first_
> TextSpanner.
> Though, the first TextSpanner is left-bounded by NoteColumn and
> right-bounded by PaperColumn.
>
> How to get the NoteColumn at first TextSpanner's end?
>
> Below some test-code.
> Obviously I can filter PaperColumn's elements for NoteColumns, but
> PaperColumn is a Score-grob, thus I get all three.
> How to select?
> (I may not know the position of the Staff with the TextSpanners)
>
> #(define tst
> (lambda (grob)
> (let* ((left-bound (ly:spanner-bound grob LEFT))
>(right-bound (ly:spanner-bound grob RIGHT))
>(ncs-from-grob
> (ly:grob-array->list (ly:grob-object grob 'note-columns)))
>(right-bound-elts
> (ly:grob-array->list
>(ly:grob-object right-bound 'elements)))
>(ncs-from-right-bound
> (filter
>(lambda (elt) (grob::has-interface elt 'note-column-interface))
>right-bound-elts))
>)
> (pretty-print
> (list
> left-bound
> right-bound
> ncs-from-grob
> (equal? left-bound (car ncs-from-grob))
> ncs-from-right-bound
> )
>
> mus = {
> bes4-\tweak #'after-line-breaking #tst
>\startTextSpan
> b\stopTextSpan
>\startTextSpan
> bis\stopTextSpan
> }
>
> <<
> { a4 a a }
> \mus
> { c' c' c' }
> >>
>
> Thanks,
> Harm
>
The only thing I can think of at the moment is to compare the
StaffSymbol of the left bound with that of each of the NoteColumns on
the right. Of course, I realize right away that that will break down
if the spanner crosses a line break. (Use an override of
'before-line-breaking?)
Here's the code I hacked up. I'll keep thinking about this.
Best,
David
%%
#(define tst
(lambda (grob)
(let* ((left-bound (ly:spanner-bound grob LEFT))
(right-bound (ly:spanner-bound grob RIGHT))
(ncs-from-grob
(ly:grob-array->list (ly:grob-object grob 'note-columns)))
(right-bound-elts
(ly:grob-array->list
(ly:grob-object right-bound 'elements)))
(ncs-from-right-bound
(filter
(lambda (elt) (grob::has-interface elt 'note-column-interface))
right-bound-elts))
(left-bound-staff-symbol (ly:grob-object left-bound 'staff-symbol))
(same-staff-right-bound-nc
(filter
(lambda (nc)
(eq? (ly:grob-object nc 'staff-symbol)
left-bound-staff-symbol))
ncs-from-right-bound))
)
(ly:grob-set-property!
(ly:grob-array-ref
(ly:grob-object (car same-staff-right-bound-nc) 'note-heads)
0)
'color red)
(pretty-print
(list
left-bound
right-bound
ncs-from-grob
(equal? left-bound (car ncs-from-grob))
ncs-from-right-bound
same-staff-right-bound-nc
)
mus = {
bes4-\tweak #'after-line-breaking #tst
\startTextSpan
b\stopTextSpan
\startTextSpan
bis\stopTextSpan
}
<<
{ a4 a a }
\mus
{ c' c' c' }
>>
How to get bounding NoteColumns of the first of consecutive TextSpanners
Hi,
please have a look at the following minimal, producing three staves,
the middle one with consecutive TextSpanners:
mus = { bes \startTextSpan b\stopTextSpan \startTextSpan bis\stopTextSpan }
<< { a4 a a } \mus { c' c' c' } >>
Now I want to know the starting and ending NoteColumns of the _first_
TextSpanner.
Though, the first TextSpanner is left-bounded by NoteColumn and
right-bounded by PaperColumn.
How to get the NoteColumn at first TextSpanner's end?
Below some test-code.
Obviously I can filter PaperColumn's elements for NoteColumns, but
PaperColumn is a Score-grob, thus I get all three.
How to select?
(I may not know the position of the Staff with the TextSpanners)
#(define tst
(lambda (grob)
(let* ((left-bound (ly:spanner-bound grob LEFT))
(right-bound (ly:spanner-bound grob RIGHT))
(ncs-from-grob
(ly:grob-array->list (ly:grob-object grob 'note-columns)))
(right-bound-elts
(ly:grob-array->list
(ly:grob-object right-bound 'elements)))
(ncs-from-right-bound
(filter
(lambda (elt) (grob::has-interface elt 'note-column-interface))
right-bound-elts))
)
(pretty-print
(list
left-bound
right-bound
ncs-from-grob
(equal? left-bound (car ncs-from-grob))
ncs-from-right-bound
)
mus = {
bes4-\tweak #'after-line-breaking #tst
\startTextSpan
b\stopTextSpan
\startTextSpan
bis\stopTextSpan
}
<<
{ a4 a a }
\mus
{ c' c' c' }
>>
Thanks,
Harm
