It appears that the listings
package provides another package, called lstdoc
, which in some unknown fashion provides facilities for printing TeX code samples while simultaneously TeXing them into the documentation itself. Looking at listings.dtx
, it seems that the samples in listings.pdf
itself were typeset in this manner. In fact, most package documentation provides such samples (code side-by-side with its effect) though I don't know how they all do it. This is actually a tricky thing to get right by hand, so lstdoc
looks like it would be useful; alas, I cannot find a single documented reference to it, neither in listings.pdf
itself nor anywhere on CTAN or the Internet in general.
My question, then: how does this package work? How can I learn about it? Even a cursory glance at listings.dtx
tells me nothing other than that it is somewhere in there.
showexpl
package provides this functionality. It is also included inydoc
which is however not stable yet.lstdoc
. However, reading the developers' docs forlistings
has alerted me to the\newdocenvironment
command, which solves a different problem that had bothered me.