[R] R CMD check and foreach code

[Duncan Murdoch]

On 27/03/2014 12:46 PM, Jannis wrote:
> On 27.03.2014 15:58, Duncan Murdoch wrote:
> > I would use a slightly less dirty hack:  call globalVariables() to
> > declare that i is global.
> >
> > The foreach() function is using nonstandard evaluation to make this
> > work, and codetools (that does the checks) doesn't know all the ins
> > and outs of it.  (foreach is in a contributed package, not base R.)
> > The globalVariables() function is a way to tell codetools that even
> > though it looks wrong, the variable is really being used safely.
> >
> > Duncan Murdoch
> >
>
> Thanks, Duncan, for your reply. So how would I use this now? Reading the
> documentation still leaves me puzzled .... Just adding
> globalVariables('i') to the dummy function like this:
>
> dummy =  function() {
>
>     globalVariables('i')
>
>     dummyfun =  function(iter) {
>       iter * 2
>     }
>     registerDoMC(4)
>     results = foreach(i = 1:10) %dopar% dummyfun(iter = i)
> }
>
>
> does not solve the problem.

The call needs to be at the global level, i.e. outside the function.

Duncan Murdoch