I was surprised by difference between using options(error=browser) and
options(error=recover) when handling an error from sys.frame that I
assume is related to the fact that the error is thrown from the
.Internal and the 'which' parameter to the closure isn't available.
> options(error=browser)
> f <- function() sys.frame(-3)
> f()
Error in sys.frame(-3) : not that many frames on the stack
Called from: sys.frame(-3)
Browse[1]> where
where 1 at #1: sys.frame(-3)
where 2: f()
Browse[1]> print(which)
function (x, arr.ind = FALSE, useNames = TRUE)
{
wh <- .Internal(which(x))
if (arr.ind && !is.null(d <- dim(x)))
arrayInd(wh, d, dimnames(x), useNames = useNames)
else wh
}
<bytecode: 0x7fe7a43f1260>
<environment: namespace:base>
Whereas:
> options(error=recover)
> f()
Error in sys.frame(-3) : not that many frames on the stack
Enter a frame number, or 0 to exit
1: f()
2: #1: sys.frame(-3)
Selection: 2
Called from: top level
Browse[1]> print(which)
[1] -3
Browse[1]>