[Rd] capturing multiple warnings in tryCatch()

[Fox, John]

Dear Adrian,

For consistency, you might want to put toreturn$value <- output$value inside of if (capture) {}. In any event, it makes sense for me to wait for the modified admisc::tryCatchWEM to find its way to CRAN rather than to maintain my own version of the function.

Thanks for this,
 John

On 2021-12-03, 6:27 PM, "R-devel on behalf of Adrian Dușa" <r-devel-bounces using r-project.org on behalf of dusa.adrian using gmail.com> wrote:

    Dear John,

    The logical argument capture is already in production use by other
    packages, but I think this is easily solved by:

    if (!is.null(output$value) & output$visible) {
        if (capture) {
            toreturn$output <- capture.output(output$value)
        }
        toreturn$value <- output$value
    }

    so that value is always part of the return list, if visible.

    This is a very good suggestion, and I've already incorporated it into this
    function.

    All the best,
    Adrian

    On Fri, 3 Dec 2021 at 21:42, Fox, John <jfox using mcmaster.ca> wrote:

    > Dear Adrian,
    >
    > Here's my slightly modified version of your function, which serves my
    > purpose:
    >
    > ------- snip -------
    >
    > tryCatchWEM <- function (expr, capture = TRUE) {
    >     toreturn <- list()
    >     output <- withVisible(withCallingHandlers(
    >         tryCatch(expr,
    >                  error = function(e) {
    >                      toreturn$error <<- e$message
    >                      NULL
    >                  }), warning = function(w) {
    >                      toreturn$warning <<- c(toreturn$warning, w$message)
    >                      invokeRestart("muffleWarning")
    >                  }, message = function(m) {
    >                      toreturn$message <<- paste(toreturn$message,
    > m$message,
    >                                                 sep = "")
    >                      invokeRestart("muffleMessage")
    >                  }))
    >     if (capture & output$visible) {
    >         if (!is.null(output$value)) {
    >             toreturn$result <- output$value
    >         }
    >     }
    >     if (length(toreturn) > 0) {
    >         return(toreturn)
    >     }
    > }
    >
    > ------- snip -------
    >
    > The two small modifications are to change the default of capture to TRUE
    > and to return output$value rather than capture.output(output$value). So a
    > suggestion would be to modify the capture argument to, say, capture=c("no",
    > "output", "value") and then something like
    >
    >         . . .
    >         capture <- match.arg(capture)
    >         . . .
    >         if (capture == "output"){
    >         toreturn$output <- capture.output(output$value)
    >         } else if (capture == "value"){
    >                 toreturn$value <- output$value
    >         }
    >         . . .
    >
    > Best,
    >  John
    >
    > On 2021-12-03, 1:56 PM, "R-devel on behalf of Adrian Dușa" <
    > r-devel-bounces using r-project.org on behalf of dusa.adrian using gmail.com> wrote:
    >
    >     On Fri, 3 Dec 2021 at 00:37, Fox, John <jfox using mcmaster.ca> wrote:
    >
    >     > Dear Henrik, Simon, and Adrian,
    >     >
    >     > As it turns out Adrian's admisc::tryCatchWEM() *almost* does what I
    > want,
    >     > which is both to capture all messages and the result of the
    > expression
    >     > (rather than the visible representation of the result). I was easily
    > able
    >     > to modify tryCatchWEM() to return the result.
    >     >
    >
    >     Glad it helps.
    >     I would be happy to improve the function, should you send a reprex
    > with the
    >     desired final result.
    >
    >     Best wishes,
    >     Adrian
    >
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    >
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