Re: Point and click in music-function

[David Kastrup]

Helge Kruse <address@hidden> writes:

> 2013/2/4 David Kastrup <address@hidden>
>
>     I have created
>     <URL:http://code.google.com/p/lilypond/issues/detail?id=3153>
>     which will
>     let all the music created within #{ ... #} point to \tr. That's
>     pretty
>     much the best you can hope to do with reasonable effort.
>
> Ah that's great I will try this, when a Lilypond version with this
> change is available.
>
> I have tried this with the code in you last mail. But this doesn't
> change the behavior. Obviously I don't have sufficient Scheme skills:
>
> tr = #(define-music-function (parser location p1 p2 p3)
>
> (ly:pitch? ly:pitch? ly:pitch?)
>
> music-map
>
> (lambda (m)
>
> (set! (ly:music-property m 'origin) location))
>
> #{ \times 2/3 { $p1 8 [ $p2 $p3 ] } #})

That's rather a lack of copy&paste skills.  You can't add or remove
parentheses in Scheme without changing the meaning.

>     A more precise
>     solution would only be possible by tacking source information onto
>     _every_ music function argument and tracing its progress in
>     expressions,
>     quite more expensive and actually also ill-defined: what is the
>     point-and-click location for the note generated by $p1 8 ? What is
>     the
>     location for the beam?
> It would be nice to get the exact position of the note in the source.

But there is no such thing as a "note" in the source.  There is just a
_pitch_.  The _note_ is only assembled inside of the #{...#}.

-- 
David Kastrup