Fix 1248

Fix 1248
 Change test from !scm_is_null to scm_is_pair

 Add regression test

[Carl, 2010-12-03 23:33:07]

Here's a proposed patch for allowing a \bookpart variable in a \book.

[Neil Puttock, 2010-12-04 00:27:01]

LGTM.

BTW, while looking into this, I was a bit puzzled by the behaviour of the
identifier inside the \book block: it isn't a \bookpart unless it's encapsulated
in another \bookpart block since the parser makes no distinction between \book
and \bookpart identifiers: the regtest snippet is functionally equivalent to the
following:

mypart = \book {
 \relative c' {
 c1
 }
}

\book {
 \mypart
}

[Patrick McCarty, 2010-12-04 01:56:52]

Hi Carl,

The code looks good.

The patch's subject should have "1428" though, not "1248".

Thanks,
Patrick

[c_sorensen, 2010-12-04 02:36:01]

On Dec 3, 2010, at 6:57 PM, "pnorcks@gmail.com" <pnorcks@gmail.com>  
wrote:

> Hi Carl,
>
> The code looks good.
>
> The patch's subject should have "1428" though, not "1248".
>
>

You know, my kids have dyslexia -- and the older I get the more it  
affects me. Thanks for the catch!

Carl