Can I please have an example of how to use the ifelse package for
LaTeX with LyX? I want to manage a NoWeb/Literate programming
document so that some commands are included in the document only
sometimes. (I'm sending LyX documents to R through Sweave:
http://wiki.lyx.org/LyX/LyxWithRThroughSweave.
This ERT makes sure that R- Sweave drops the images in a folder "foo"
and prefixes all with "bar".
\SweaveOpts{prefix.string=foo/bar}
This is a NoWeb "code chunk" that will create an image in foo called
bar-testfn.eps.
<<testfn, fig=true, include=false>>=
curve(sin, from = 1, to = 5)
@
Then the image can be used later with some LaTeX:
\includegraphics{foo/bar-testfn}
I would like to conditionalize the figure creation, so that only when
I really want new figures will the code chunk be executed.
In the r-help list I asked about ways to avoid re-doing calculations,
but the answers were focused on ways in which R calculations can be
cached, rather than avoiding asking R for calculations in the first
place. Since I am doing this work within LyX, and LyX has its own way
of handling the temporary LaTeX files, it is not immediately apparent
that the caching strategies proposed from within R are going to help
(the LyX "current working directory" is an unpredictable directory
inside /tmp while the R working directory is inside there, and the R
stuff disappears once LyX exits.
I'm sorry, this is hard to explain. If you can just give me a
concrete ifthen example in ERT, I think I can make it work. I just
don't understand the ifelse package instructions because they assume a
person is fluent in LaTeX.
pj
--
Paul E. Johnson
Professor, Political Science
1541 Lilac Lane, Room 504
University of Kansas
