On 9/21/10 7:28 PM, "Jeff Epstein" <aliteralmind-lilyp...@yahoo.com> wrote:
>
> I'm not sure what I'm missing here. Is there a translation between an ly
> property and scheme? "box-padding" does exist in the Internal Reference
> manual,
> and I've not yet found anything in the other manuals, nor in this forum
> (searching for scheme property override), that strike me as relevant.
>
> If anyone could point me in the right direction, I would appreciate it.
> Thanks.
>
Excellent question. Thanks for sharing enough that we could answer it well.
You're doing everything right! But the \displayMusic function missed a
quote that you need in your argument list--note that it should be
#:override '(box-padding . 0.5) not
#:override (box-padding . 0.5)
:
%%%%%
#(define-markup-command (mBox layout props s_boxText)
(string?)
"Print the given string in a box and small-caps. Example usage:
c4.^\\markup \\mBox \"section a\""
(interpret-markup layout props
(markup #:center-align #:override '(box-padding . 0.5) #:box #:caps
s_boxText)))
\relative c' {
c1^\markup \mBox #"Section a"
}
%%%%%
The purpose of the initial ' is to prevent Scheme from trying to evaluate
the expression inside the parentheses. Since the ' was missing, it tried to
evaluate box-padding, but box-padding hasn't been defined as a Scheme
variable. It's just a scheme symbol (which is different).
By putting the ' before (box-padding . 0.5) we accept this as a cons cell
that will be added onto the property alist.
We get so used to prefacing alists with ' that we automatically put them
there in our minds. I don't know why \displayMusic *didn't* put the quote
there, but the fact that it didn't is a bug.
Could you please file a simple bug report at bug-lilyp...@gnu.org?
Thanks,
Carl
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