[Rd] require is to suggests as what is to imports?

[Dirk Eddelbuettel]

On 24 August 2010 at 15:40, Hadley Wickham wrote:
| Hi all,
| 
| If a package suggests another package in its description, you can
| check it at runtime with requires.  How do you do check if a package
| is available without loading it, if you only want to access one
| function in the package namespace.

I needed this a few days ago for a small package and resorted to this:

   .packages <- as.character(installed.packages()[,1])

   [...]

   hasGputools <- function() {
       any( "gputools" == .packages )
   }

That way I get around Depends, Suggests and other thing that may impact the
running of 'R CMD check' and friends.

Dirk

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