Not desperately important, but nice to have and possibly of use to
others, is the ability to suppress specific warnings rather than
suppressing warnings indiscriminately. I often know of a specific
warning that I want to ignore (because I know that's it's a false
positive/ignorable), but the current design of suppressWarnings() forces
me to ignore *any* warnings coming from the expression.
I started to write a new version that would check and, if supplied
with a regular expression, would only block matching warnings and
otherwise would produce the warnings as usual, but I don't quite know
enough about what I'm doing: see ??? in expression below.
Can anyone help, or suggest pointers to relevant
examples/documentation (I've looked at demo(error.catching), which isn't
helping me ... ?)
suppressWarnings2 <- function(expr,regex=NULL) {
opts <- options(warn = -1)
on.exit(options(opts))
withCallingHandlers(expr, warning = function(w) {
## browser()
if (is.null(regex) || grepl(w[["message"]],regex)) {
invokeRestart("muffleWarning")
} else {
## ? what do I here to get the warning issued?
## browser()
## computeRestarts() shows "browser",
## "muffleWarning", and "abort" ...
options(opts)
warning(w$message)
## how can I get back from here to the calling point
## *without* muffling warnings ... ?
}
})
}
suppressWarnings2(sqrt(-1))
suppressWarnings2(sqrt(-1),"abc")
It seems to me I'd like to have a restart option that just returns to
the point where the warning was caught, *without* muffling warnings ...
? But I don't quite understand how to set one up ...
Ben Bolker
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