[Feature Request] \compressFullBarRests improvement(s)

[Kieren MacMillan]

Hello all,

Consider this snippet:

\version "2.17.97"

theMusic = {
  \compressFullBarRests
  R1*2
  R1*2
}

\score {
  \theMusic
}

Here’s my request: I would love it if \compressFullBarRests actually did what 
it says it does…  ;)

See <http://lists.gnu.org/archive/html/lilypond-user/2013-10/msg00517.html> for 
more discussion on this request.

Despite David K’s suggestions that it might be difficult to work out what the 
user wants/means or what the output “should be”, I believe we can come up with 
a pretty simple single rule which covers >90% of the cases perfectly. As a 
first attempt, I would suggest the following:

    \compressFullBarRests will combine any contiguous block of multi-measure 
rests (within the same context*) which is uninterrupted by any "notation 
item”** other than a barline***.

Notes:
* This may be up for discussion — though, again, it will more than suffice for 
>90% of use cases.
** This wording sucks; needs “official” wording.
*** There may be other items I’m not thinking of which are “outputtable" grobs 
which nevertheless should *not* split a compressed block of MMRs.

Having just engraved nearly 25 minutes of music resulting in 57 different 
individual parts, I can tell you that this issue inspired quite a bit of 
reduced efficiency, increased hackery, and even some loud swearing.  =)

Thoughts?

Thanks,
Kieren.