On 2023-12-17 9:33 pm, Mark Probert wrote:
Hi.
I'm struggling some with writing a music function for rests. Basically
I
want to be able to write something like
\rel-rest( b', 1)
Minor nit: Functions in LilyPond do not use parentheses and commas for
arguments in this way. You need only say something like the following
to invoke your function:
%%%%
\rel-rest b' 1
%%%%
which would place a dotted quarter rest on the indicated pitch (the
equivalent of
b'1\rest
I'm starting with
rel-rest =
#(define-music-function (pit dur) (ly:pitch? ly:duration?)
#{
#pit#dur\rest
#})
but that gives me an error.
Any suggestions?
There are a few things the errors in the output log should be
communicating.
Unbound variable: #{pit\#dur\\rest}#
Firstly, whitespace is important in Scheme. Jamming together
#pit#dur\rest gives the parser little hope to understand what you mean.
It thinks this refers to a singular named thing, which in this context
does not exist.
So, give each part of that expression some room to breathe:
;;;;
#pit #dur \rest
;;;;
But then LilyPond is not satisfied that this represents a valid music
expression. When using variables, often the number sign (#) is correct,
however there are some spots when you need to use the dollar sign ($)
instead.
;;;;
$pit $dur \rest
;;;;
Lastly, I am not sure why using the duration "1" as you indicated would
result in a dotted quarter rest. Did you mean "4." or is the point of
the music function to manipulate the inputs in some way? I am not sure
I see the connection/logic there, so you are going to be a bit on your
own there.
But with the modification indicated above, you can now do this:
%%%%
{ \rel-rest b' 4. }
%% ...or even...
{ \rel-rest b'4. }
%%%%
However, this feels like more typing than just using the \rest
post-event, apart from being prefixed.
-- Aaron Hill
