Re: Extracting header fields for use by e.g. LaTeX?

[Michael Haynie]

That looks like a nice hook.

I suppose I'd also have to tell lilypond to not generate the header for 
each song somehow, since I'm going to be handling that myself.

The change to \preLilypondExample can be made backward compatible by 
defining a variable that preLilypondExample can rely on -- it's a bit 
of a hack, though.  Using a parameter might be worth a little breakage, 
since there will not likely be a huge number of places to edit.

One thing, though: using 2.6.4 (on Mac OS X, at least), lilypond-book 
seems to insist on parsing the --process arguments, and so complains 
that -b isn't a valid option.  If a patch is possible against 2.6, that 
should also be corrected.

I'll be delighted to test the patch.

On Nov 27, 2005, at 5:22 PM, Bernard Hurley wrote:

> On Sun, 2005-11-27 at 13:13 -0500, Michael Haynie wrote:
> > Yes, that's exactly what I was thinking about doing.
> >
> > So: Which scheme functions do I need to replace to accomplish that?
> > Are the suggested hooks are documented/supported hooks?
>
> I don't think scheme is going to help. I thnk the solution is to modify
> lilypond-book slightly.
>
> However if you take the files
>
> --- test.lytex ---
> \documentclass{article}
> \usepackage{graphicx}
> \begin{document}
> \lilypondfile{test.ly}
> \end{document}
> ------------------
>
> and
> ---- test.ly -------
> \version "2.7.18"
>
> \header {
>     title="The test title"
>     composer="Bernard Hurley"
> }
>
> {a b c}
> --------------------
>
> and run:
> lilypond-book --psfonts --process="lilypond -b eps -H title " 
> test.lytex
>
> you get a file called something like:
>
> lily-1915112629.title
>
> which contains the text of the header "title" - you can do the same 
> with
> any other header.
>
> in addition to the generated test.tex
>
> Now the file test.tex contains the code:
>
> -------------test.tex------------
> ........
> \ifx\preLilyPondExample \undefined
>   \relax
> \else
>   \preLilyPondExample
> \fi
> \def\lilypondbook{}%
> \input lily-1915112629-systems.tex
> .......
> --------------------------------
>
> Now
> \input lily-1915112629-systems.tex
> Notice:
> 1] The files lily-1915112629-systems.tex and lily-1915112629.title both
> start with "lily-1915112629" so this prefix must be available to
> lilypond-book when it generates this code.
> 2] notice the macro call \preLilyPondExample (it only takes effect if
> the macro is defined). If lilypond-book were modified so that it
> generated the parameter {lily-1915112629}. Then it would be possible 
> for
> you to define the macro so that it read the file with the header.
>
> Actually this modification looks quite easy. The real problem is 
> whether
> this would break any existing lytex code. (It can't be upgraded with
> convert-ly because that just upgrades lily files). Another solution
> would be to have two user-definable macros in the same place, which
> seems a bit silly.
>
> I'll have a think about it and then submit a patch.
>
> --
> Bernard Hurley <address@hidden>