3 problems with LilyPond 2.12.3.1

[Phil Holmes]

Not sure if these should be posted together or as separate threads, but here 
goes anyway.  I've today encountered 3 issues with LilyPond, one of which I 
think is a bug and the other 2 are features that I'd like advice on.

1.  If you have the following line in the source file:

"#(set-global-staff-size 0)"

LilyPond gets into a loop of writing:

 "programming error: Improbable offset for stencil: NaN staff space
 Setting to zero."

to the logfile.  After 30 seconds I kill the process and the logfile is 
almost a meg.  Clearly I shouldn't set a staff size to zero, but I think 
LilyPond should detect this, issue a warning, and exit.  Could one of the 
developers check whether this is a bug?

2.  I'm trying to engrave a song which uses numerals as its sole lyrics.  It 
appears that LilyPond won't accept numerals in lyrics at all.  Is this true, 
and can anyone point me at a workaround, please?

3. The original music I'm re-typesetting uses beamed quavers in the vocal 
line.  If I try to replicate this, then the beamed set of quavers will only 
accommodate one lyric syllable, rather than the 2 or 4 in the original.  Is 
there a way of changing this behaviour so that each beamed quaver 
accommodates a syllable, and it's only slurs that make more than one note 
per syllable?

Thanks in advance.

--
Phil Holmes