Re: music function to be included somewhere in scm/*

[Knut Petersen]

Hi Urs!
> My gut feeling says: Yes, this is an improvement and should be there by
> default. IIUC the reason why this has to be discussed is because that
> could change/break existing scores, right?
>
> If so, could you please think about an example where the patch would
> have a negative impact that can't reasonably be caught by convert-ly?
> Just because you two are much more into the topic, so that could help us
> others understand ...

For the changes to the lyric-extender.cc:

There is no "__":
====================
nothing changes.

There is a melisma and "__" in the lyrics:
=============================================
Old behaviour: print an extender line. Even if there is no place: print an 
extender line
New behaviour: print an extender line only if the extender line is longer than 
minimum-length.

There is no melisma but there is "__" in the lyrics.
======================================================
Old behaviour: print a short extender line.
New behaviour: print an extender line of minimum-length only if forced by the 
new force-extender
boolean property.

In other words: Never ever print an extender line if there is no melisma unless 
forced with new syntax.
Some code needs to be (and can be) converted, e.g. 
http://lsr.di.unimi.it/LSR/Item?id=1006

Advantages:

With a music function \autoextenders that adds extender events to every 
syllable you
- can be sure never to forget extenders,
- can be sure never to generate too short extenders
- can use the same lyrics definition for voices that require extenders at 
different places.

Nobody is forced to use \autoextenders, manual definition is still possible.

cu,
 Knut