As I really like the simplicity and quality of ReStructeredText, I do more of my notes intended also for other people in it. For small texts, rst2pdf does a good job and is so simple that it can easily be called from the command line without further ado. But still, it is a traditional "edit-compile-debug" cycle that surely can be automated.
Of course under Linux there is the powerful
inotify mechanism, but
until now I did not use that directly from the command line. Some
apt-cache browsing later I installed the "inotify-tools" package containing
inotifywait command line utility.
With that in place, one can do a simple two-liner like this:
( while : ; do rst2pdf doc.rst ; inotifywait doc.rst ; done ) & \ sleep 1 ; evince doc.pdf
This will process the file and infinitely rerun
rst2pdf again when
the source file has changed. The sleep 1 is intended to wait for the
first rendering of the file so that evince can start successfully. Of
course the one second constant is ugly and surely one can get rid of
it, but that requires significantly more characters and thus blows the
scope of this short entry.
It remains to be said that evince is clever enough to monitor the PDF file by itself, so it automatically updates the display when a new rendering is done. Thus with this simple while loop we have created a "fully event driven" rendering pipeline without any polling and saving the file in the editor automatically updates the PDF window.