[Rd] Incorporating single functions from other packages: rules and regulations?

[Johannes Graumann]

Hi,

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.

What is an acceptable way of integrating this functionality into my own 
package? Just copying the function and referencing it in the documentation 
appropriately?

Thanks for any hints.

Sincerely, Joh