how to stop without error message?

Thank you Hadley & John

Hadley's approach below is the kind of thing I was expecting-- I'd just never managed to figure out how to use tryCatch. John has also made me think that I could probably patch things up by modifying my calls to 'try'-- because sometimes I do want to print the error messages from the 'try's, it just depends on what they are. On balance, it's probably time for me to get to get to grips with 'tryCatch'.

Thanks again

mark




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Mark Bravington
CSIRO Mathematical & Information Sciences
Marine Laboratory
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-----Original Message-----
From: hadley wickham [mailto:h.wickham at gmail.com]
Sent: Tuesday, 11 November 2008 2:20 PM
To: Bravington, Mark (CMIS, Hobart)
Cc: R-help at r-project.org
Subject: Re: [R] how to stop without error message?

I should have been clearer, sorry-- I'm trying to exit from an "inner" function which might be several levels deep, returning straight to the R prompt. To be specific, I'm trying to clean up the "No Error in..." message in my 'debug' package-- the "No " prefix being my original workaround to avoid an unnecessarily alarming message.

Ah, ok.  How about signalling custom condition then?

f <- function() {
  print("a")
  g()
  print("d")
}

g <- function() {
  print("b")
  error <- simpleError("")
  class(error) <- c("myerror", class(error))
  signalCondition(error)
  print("c")
}

f()
tryCatch(f(), myerror = function(...) print("stopped!"))

Hadley


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