Re: Event listener to extract (some) music events. (issue4373046)

[percival . music . ca]

On 2011/04/22 18:25:19, Neil Puttock wrote:
> On 18 April 2011 15:30,  <mailto:address@hidden> wrote:
> > On 2011/04/18 14:09:52, hanwenn wrote:

> >> In that case, it would probably be cleaner to
> >> hook into the event listener framework directly, without having an
> >> engraver in between. &nbsp;The Scheme engraver mechanism is really
for
> >> creating formatted output rather than siphoning off data.
> >
> > I have no clue how to do this? &nbsp;Is this simple to do with a .ly
file? &nbsp;I
> > definitely don't want to mess with C++ code or SCM files.

> You don't have to do that; there are exported functions which provide
> all the hooks.

> http://lists.gnu.org/archive/html/lilypond-user/2010-02/msg00688.html

Sorry, I'm still lost.  Is the idea that I add stuff like this at the
top level?
#(ly:add-listener
   (ly:make-listener
    format-note)
   (ly:context-events-below
    (ly:make-global-context $defaultlayout))
   'note-event)

I definitely don't want to create a music function, since that would
require manually editing lots of files -- it's much easier just to
  cat "\include \"event-listener.ly\"" file-1234.ly >> tempfile.ly
rather than making some regex to add a music function call to the \score
section of each file.

Unless there's some fantastic advantage that I'm missing (I doubt that
there would be a big speed difference, and even if there was, speed
isn't a primary concern), I think that modifying the Voice context is
clearer from a "writing easily understandable code" perspective.
Advanced users are already familiar with adding tweaks to a \layout
\context, after all.


http://codereview.appspot.com/4373046/