Re: Determining location of the staff lines

[Carl Sorensen]

On 2/17/10 9:08 AM, "Eric Knapp" <address@hidden> wrote:

> On Mon, Feb 15, 2010 at 11:54 AM, Carl Sorensen <address@hidden> wrote:
>> 
>> 
>> I think it's not yet possible to do this in a Scheme engraver.
>> 
>> Han-Wen indicated that it could be done here:
>> 
>> http://lists.gnu.org/archive/html/lilypond-devel/2010-01/msg00594.html
>> 
>> But I don't think it's been implemented yet.  Perhaps Han-Wen will do so,
>> now that we've identified a need.
>> 
> 
> This is good to know. I thought I was losing my chops for learning new
> languages! Now I'm relieved to know that it's not just me and that
> might be a new feature. When Han-Wen says "I had thought the Scheme
> engravers to use context properties to store internal state" what was
> envisioned? Can arbitrary properties be added to the context or are
> there properties that can be used for new data?
> 
Yes, arbitrary properties can be added to the context.  Context properties
are stored as scheme alists.  So that is a potential workaround that you
could use now -- store the private data in a context property (which makes
it not private, but nobody else is using it so it's pseudo-provate).

>>> 
>>> How do I create the vectors in Scheme so that they are persistent?
>>> Everything I've tried has resulted in only having the last item in the
>>> vector there once I'm done.
>> 
>> We need to have the capability to store private data in Scheme engravers.
>> Hopefully we can get that implemented.
>> 
> 
> I'm assuming that context properties can't be used for this?

They probably can, but it's not the normal way of working.

> 
> This is helping greatly and I sincerely appreciate your detailed and
> clear answers.


You're welcome.  I'm a little nervous sometimes that my answers may not be
strictly correct, but I'm doing my best.

Thanks,

Carl