Re: lybook-db etc etc.

[Reinhold Kainhofer]

Am 2011-10-26 17:13, schrieb David Kastrup:
> Well, I am currently in the process of running make info (similar to
> make doc), and this is totally silly.
>
> In my opinion, the whole lybook-db stuff needs to go.  Instead, Lilypond
> is run _once_ for all snippets of a lybook source,

Lilypond is currently run _once_ for all snippets. In particular, it is 
called by lilypond-book with snippet-names.* as input file, listing all 
files to process.

> generating _one_
> PostScript file.  Then GhostScript is run _once_ to generate a bunch of
> eps files, or a multi-page PDF file with all graphics in them which get
> referenced as needed.

This is a fundamental deviation from how lilypond works currently, and 
it's probably hard to get it right.
Currently, lilypond processes one file after the other in a loop, 
properly cleaning up after each file, and the corresponding backend does 
its job one file at a time.

You are proposing that all backends should be split into two stages, one 
to create the ps files (for the (|e)ps backend at least) and one to 
convert them to pdf/pngs. This does not affect only lilypond-book, but 
lilypond being run on multiple files in general.

What if one file fails to compile? Imagine you are running multiple 
files at once, i.e.
  lilypond file1.ly file2.ly file3.ly file4.ly
and file4.ly contains a syntax error. So far, file1, file2 and file3 
will have been properly processed and finished (i.e. their 
*.pdf/svg/eps/ps/scm output files have been created), only file4 failed.

With your proposal, all already compiles files will have only half of 
the work done, but no PDF created. So basically you will have NO pdf 
output at all for any of the files.

> Bleedover of variables/fonts/whatever is not all that crucial since we
> are talking about a single document source rather than an immaculate
> database.

How does your proposal work with files that e.g. change the scheme 
options, like resolution? (Well, I think this case doesn't work properly 
right now, either, because the option might not be reset after the file 
that sets it, but at least each file can be compiled with different 
settings).

> And would definitely simplify the build system.

Actually, it will not simplify the build system that much. All the work 
you are describing is done by lilypond-book, and the build system only 
calls lilypond-book on the list of snippets (with some copying of output 
files, of course, which complicates things; that will be simplified).

Cheers,
Reinhold

--
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial&  Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org