Re: manual beaming and variables

[Gianmaria Lari]

On 3 September 2017 at 22:34, David Kastrup <address@hidden> wrote:

[....]

 

> Well, you can cheat by going inside of chords like
>
> \version "2.19.60"
>
> nc = c_3
> nd = d_2
> ne = e_3
> nf = f_4
>
> {

>   \fixed c' {<\nc>8 [ <\nd> <\ne> <\nf>]}
>   \fixed c' {<\nc>16 [ <\nd> <\ne> <\nf>]}
> }
>
>
> since then the durations get removed and reassigned, but you are hardly
> going to make your source code more readable by that.
>
> I think you are likely better off by creating music functions for the
> job.

Here is how to do this cheaply:

\version "2.19.60"

wf =
#(define-scheme-function (p f) (ly:pitch? ly:event?)
  (define-music-function () () #{ $p $f #}))

nc = \wf c_3
nd = \wf d_2
ne = \wf e_3
nf = \wf f_4

{
  \fixed c' {<>8 [\nc \nd \ne <>] \nf}
  \fixed c' {<>16 [\nc \nd \ne <>] \nf}
}

Now the <>] thingy is still sort of ugly.  I have a patch that can get
rid of it.  In fact, that patch also makes your example in the first
post in this thread compile.

And it has lots of other implications.  Like letting

{ c \tweak color #red \p }

work as expected.  However, it also has some strange consequences.  When
writing

{ \displayLilyMusic c \tweak color #red \p }

the dynamic will not be included in the output while with

{ \displayLilyMusic c -\tweak color #red \p }

it will.  The reason is that in the first case, LilyPond has no way of
knowing whether \tweak color #red \p is a post-event or not before
calling \tweak, and if it were to end up _not_ being a post-event,
\displayLilyMusic should have gotten evaluated before \tweak even got
called.  So basically LilyPond processes things as normal but allows
spurious post events to remain in braced lists and does another pass
sweeping them into the right expressions before further processing.

For people who want to be in full understanding what is happening, this
might be puzzling.  For people who want to have things "just work", it
might often produce useful results before they start asking questions.

--
David Kastrup

I tried your example and it works, thank you David for this escamotage!

g.