The following code produces an error in current R-devel
f <- function(value) {
if(!missing(value))
100
else
2
}
e <- new.env()
makeActiveBinding("x", f, e)
eval(substitute(list(x)), e)
The error, after calling 'eval' is
Error in eval(expr, envir, enclos) :
element 1 is empty;
the part of the args list of 'list' being evaluated was:
(x)
It has something to do with the change in R_isMissing in revision
r48118 but I'm not quite knowledgeable enough to understand what the
problem is. In R 2.8.1 the result was simply
> eval(substitute(list(x)), e)
[[1]]
[1] 2
I can't say I know what the output should be but I'd like some
clarification on whether this is a bug.
Thanks,
-roger
--
Roger D. Peng | http://www.biostat.jhsph.edu/~rpeng/
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