[Rd] what is the preferred method to create a package local variable?

[Roger Peng]

I usually use environments for this. So, in one of the R files for the
package, just do

.localstuff <- new.env()

Then, in functions you can do things like

.localstuff$bbg.db.conn <- dbConnect(...)

-roger

On Tue, Mar 31, 2009 at 11:45 AM, Whit Armstrong
<armstrong.whit at gmail.com> wrote:
> for the moment, I'm using:
>
> .onAttach <- function(libname, pkgname) {
>    .bbg.db.conn <<- dbConnect(dbDriver("PostgreSQL"), user="blah","blah")
> }
>
> .onUnload <- function(libpath) {
>    dbDisconnect(.bbg.db.conn)
> }
>
>
> which results in a hidden global variable in the global environment.
>
> I would prefer to make the assignment only in the package namespace.
> I've looked at assignInNamespace, but I can't seem to make it work.
>
> Is there a preferred method for doing this?
>
> When I try adding an assignment directly in the source file, I get the
> "cannot change value of locked binding" error.
>
> What am I missing?
>
> Thanks,
> Whit
>
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-- 
Roger D. Peng  |  http://www.biostat.jhsph.edu/~rpeng/