Gnumeric plugins typically either define a file format (input and/or output)
or a set of functions.  Nothing prevents a mixture -- that is just how things
have turned out so far.

When you add or delete files, don't forget...

* Edit po/POTFILES.in
* Edit configure.in






File-format plugins
--------------------

For a good skeleton, grab a copy of the applix plugin.  (The Excel plugin is
the most sophisticated, but it is currently statically linked into Gnumeric.
It will probably become a regular plugin at some point.)



Plugins containing functions
-----------------------------

For a good skeleton, grab a copy of the numtheory plugin.
