Re: book-predicate

[Jan-Peter Voigt]

Again: Thank you, David!

So now (with upcoming 2.15.31 or 2.16) one can write functions like:

--snip--
bookif = #(define-scheme-function (parser location book pred)(ly:book? 
procedure?)
       (if (pred parser location)(collect-bookpart-for-book parser book) ))
--snip--

to conditionally add bookparts or create books:

--snip--
writeBook = #(define-scheme-function (parser location book paper layout 
file)(ly:book? ly:output-def? ly:output-def? string?)
  (ly:book-process book paper layout file))
--snip--

(I know, it would also work with a scheme?-predicate, but type-safety is 
IMHO a good thing ;-) )

Cheers, Jan-Peter

On 27.02.2012 10:10, David Kastrup wrote:
> Jan-Peter Voigt<address@hidden>  writes:
>
> > > Am 24.02.2012 um 16:24 schrieb:
> > >
> > > > Jan-Peter Voigt<address@hidden>  writes:
> > > >
> > > > > Hello list,
> > > > >
> > > > > when I use books or bookparts for (scheme-)function arguments, I
> > > > > haven't found the predicate for it.
> > > > > paper-book? is something else, or am I missing something?
> > > > Well, you can always use scheme? and file a feature request in the mean
> > > > time.
> > Thank you David,
> >
> > the scheme?-solution is what I do right now. I will send a feature
> > request next days.
> Don't bother.
>
> commit 09814b549186893c265bcdf835edbe242f6354cf
> Author: David Kastrup<address@hidden>
> Date:   Sun Feb 26 11:23:39 2012 +0100
>
>      Implement ly:book? and ly:context-def? predicates
>
> Note that a bookpart _is_ a book as well, usually without a paper block
> of its own.