lilypond-book and comments stop generation of \usepackage Ver 2.7.20/ChangeLog/1.4313/

[Bernard Hurley]

Hi,

Tests running 
        lilypond-book -V --psfonts testx.lytex
On files testx.lytex. with latest CVS version (1.4313)

----------------- test1.lytex ----------------  ----------------- test1.tex 
----------------
%% comment                                      %% comment
\documentclass[english]{article}                \documentclass[english]{article}
\begin{document}                                \begin{document}
\end{document}                                  \end{document}

----------------- test2.lytex ----------------  ----------------- test2.tex 
----------------
\documentclass[english]{article}                \documentclass[english]{article}
%% comment                                      %% comment
\begin{document}                                \begin{document}
\end{document}                                  \end{document}


The code for detecting whether graphics pakages are already loaded does
not work when the package is loaded as a parameter to the main class:

----------------- test3.lytex ----------------  ----------------- test3.tex 
----------------
\documentclass[graphics]{article}               
\documentclass[graphics]{article}
\begin{document}                                \usepackage{graphics}
\end{document}                                  \begin{document}
                                                \end{document}

Some points:

1] Detecting whether LaTeX would have loaded the graphics package by the
time you get to \begin{document} is impossible unless you are going to
parse LaTeX package files. I have been involved in LaTeX projects where
we commonly needed to load about 20 packages. So what we did was load
them in a .sty file, and only had to use one \usepackage instead of 20.

2] If the issue is whether "graphics" or "graphicx" has been loaded by
the time you get to \begin{document}, then it is a non-issue, LaTeX will
ignore the \usepackage{graphics} if either are loaded.

3] However there still is an issue here. Suppose in five years time
someone writes a package "fungraphics" that includes the same interface
as "graphics" but is inconsistent with it. (Stranger things have
happened!) if someone used \usepackage{fungraphics} in the preamble to
a .lytex file then lilypond-book would produce invalid LaTeX.

SO it is _not_ worth trying to see whether "graphics" or "graphicsx"
would have been loaded, and it actually doesn't matter.

BUT there is an issue of giving the user the option of _not_ generating
\usepackage{graphics}. This could be done by a command line switch or
maybe better with a directive like:

        \lilypondGraphicsAlreadyLoaded

which would suppress the generation of "\usepackage{graphics}" if added
to the preamble.

-- 
Bernard Hurley <address@hidden>