Incorporating single functions from other packages: rules and regulations?

| In a little pkg I'm developing I am in need of the functionality provided by 
| plotrix::listDepth.
| 
| I am loath of having the depend on and import the whole package just for 
| that purpose.

Step back and realize that your total R installation (including all packages)
is already much bigger than the single package. And derives value from all
those packages.

So I would use importForm(plotrix, listDepth) in my package's NAMESPACE, and
add the Imports: in the DESCRIPTION.

IMHO that is the right way to do it rather than creating _stale_ and (even
worse) _disconnected_ copies which will never receive updates or fixes from
the _original author_ of that code.

Dirk

Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com