Fix for issue 1173 to fails when asked to showLastLength on partial measures.

Fix for issue 1173 to fails when asked to showLastLength on partial measures.

Fixes 1173 no error message rounds up to the next measure

Patch from Mike Solomon.

[Neil Puttock, 2010-08-04 21:18:44]

Hi Mike,

Here are some general comments following testing:

-) showFirstLength still doesn't work

-) probably related to the above, but the combination of showFirstLength and
showLastLength doesn't work

-) if there's no time signature, showLastLength is ignored; this breaks several
regtests (should assume 4/4 in this case)

On a more serious note, I tested some real-world files, and one of them crashed
with an infinite loop in libguile (I can post the file if it helps):

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7931bdc in ?? () from /usr/lib/libguile.so.17
(gdb) bt
#0  0x00007ffff7931bdc in ?? () from /usr/lib/libguile.so.17
#1  0x00007ffff7932299 in ?? () from /usr/lib/libguile.so.17
#2  0x00007ffff7932f90 in ?? () from /usr/lib/libguile.so.17
#3  0x00007ffff7932299 in ?? () from /usr/lib/libguile.so.17
#4  0x00007ffff793231d in ?? () from /usr/lib/libguile.so.17

(etc.)

Cheers,
Neil

[Neil Puttock, 2010-08-04 21:38:52]

http://codereview.appspot.com/1741060/diff/1/4
File scm/music-functions.scm (right):

http://codereview.appspot.com/1741060/diff/1/4#newcode534
scm/music-functions.scm:534: (set! (ly:music-property m 'den) den)
These should come from the music (which means you'll be needing a fix for issue
#1198: \time requires a synthetic music object to generate the context property
settings).

We already have two music properties called `numerator' and `denominator' which
could be used (it even appears that they might originally have had this purpose,
judging by the docstrings, even though they're currently used for \times)

http://codereview.appspot.com/1741060/diff/1/4#newcode932
scm/music-functions.scm:932: (define (generate-timing-alist music)
needs a docstring

(+ others below)

http://codereview.appspot.com/1741060/diff/1/4#newcode936
scm/music-functions.scm:936: (define (time-helper music)
Following a fix for #1198, this could be simplified

http://codereview.appspot.com/1741060/diff/1/4#newcode1035
scm/music-functions.scm:1035: (integrated-measures
This looks rather costly, since it will be called for all scores, even if
show(First|Last)Length isn't set (skip-as-needed is a top-level music function,
so it's applied automatically whenever the parser encounters music)