Re: scheme spanner in input/regression/scheme-text-spanner.ly not quote-proof

[Reinhold Kainhofer]

On 28/07/2012 07:32, David Kastrup wrote:
> Reinhold Kainhofer <address@hidden> writes:
>
>> The text spanner implemented in scheme (which is also used as a basis
>> for David's measure counter engraver) seems to work fine in the regtest,
>> but apparently it is not quote-proof.
>>
>> In particular, if you try call \addQuote on some music that contains
>> \schemeTextSpannerStart or \schemeTextSpannerEnd, then you get the
>> following warnings and the text spanner is not quoted:
> Well, scheme-text-spanner changes the \Global context, and quote
> environments uses the layout definition partCombineListener in
> ly/declarations-init.ly with an unchanged Global context.
>
> Change its Global context similarly, and you should be set.

How can a user, who wants to use e.g. the measure counter engraver,
change the partCombineListener' s Global context without messing with
the original lilypond sources? Am I missing something?
The whole point of scheme engravers and scheme text spanners is that
users can now also implement things in scheme without messing with the
lilypond sources...
If I understand you right, then the user cannot add new grobs in an
include file without messing with the lilypond sources.

Would a proper solution be to change the partCombineListener to a
context mod and construct the real listener when we need it (i.e.
replace the current (ly:parser-lookup parser 'partCombineListener) by
the actual creation of the listener from the context in effect when
add-quotable or recording-group-emulate is called?
However, I don't really have enough knowledge about how to create the
actual listener in scheme and insert a given context mod in scheme...

Cheers,
Reinhold

-- 
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://www.kainhofer.com
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * Edition Kainhofer, Music Publisher, http://www.edition-kainhofer.com