Output break positions (question or feature request)

[Urs Liska]

Hi,

as asked on the -user list I am looking for a way to collect the 
positions of all breaks in a LilyPond score.
http://lists.gnu.org/archive/html/lilypond-user/2015-01/msg00185.html 
suggests that at the time engravers are doing their work the line and 
page breaking hasn't been performed so engravers can't help with that. 
But I'm quite sure LilyPond *has* a way to produce this information somehow.

The goal is to find a way to recompile just a certain page or system 
using the skipTypesetting property, which works well for entering or 
editing music as long as the changes don't require changed breakings 
(which would then require a complete recompilation, resulting in a new 
list of breaks.

So I have
a) the question if there already *is* a way to retrieve the moments 
(barnumber plus measure-position) of all explicit and implicit breaks in 
a score and write them to a log file?
b) if it's confirmed that currently there is no way to do so please add 
this as a feature request to the tracker.

I hope to make this an editing option (in Frescobaldi, but it could be 
adapted to other editing environments as well) that can dramatically 
reduce waiting times while editing the *content* of a LilyPond score, 
making the overall user experience significantly smoother. I hope that 
this may significantly increase acceptance of LilyPond with potential users.

Best
Urs