[Bioc-devel] limma Suggests:statmod vs Imports:statmod

[Robert Castelo]

hi,

this is a question for limma developers.

at every new fresh installation of BioC and limma i get this message 
when i use 'duplicateCorrelation()':

"statmod package required but is not installed"

i just install 'statmod' and problem solved. this, however, triggers 
questions from some of my students since they expect that BioC 
dependencies within functions are automatically installed when the 
desired package is installed for the first time.

i've observed within the limma source that the 'statmod' functionality 
is used within other functions and in all cases this is dealt as in 
'duplicateCorrelation()', where first it's checked whether the package 
namespace can be loaded and the user is asked otherwise to install it:

if(!requireNamespace("statmod",quietly=TRUE)) stop("statmod package 
required but is not installed")

and the 'statmod' package is listed in the 'Suggests:' field of the 
DESCRIPTION file.

just out of curiosity, is there a particular reason to import the 
functionality of 'statmod' in this way? wouldn't be possible to do it 
via 'Imports:'?


thanks!

robert.