[Rd] suppress *specific* warnings?

Ben Bolker bbolker at gmail.com
Sun Oct 21 21:28:03 CEST 2012

  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)
    withCallingHandlers(expr, warning = function(w) {
        ## browser()
        if (is.null(regex) || grepl(w[["message"]],regex)) {
        } else {
            ## ? what do I here to get the warning issued?
            ## browser()
            ## computeRestarts() shows "browser",
            ##    "muffleWarning", and "abort" ...
            ## how can I get back from here to the calling point
            ##   *without* muffling warnings ... ?


  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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