[Rd] Possible repeat{} / break function bug in R 3.4.1

[Martin Maechler]

>>>>> Martin Maechler <maechler at stat.math.ethz.ch>
>>>>>     on Wed, 23 Aug 2017 09:10:20 +0200 writes:

>>>>> Peter Bosa <Peter.Bosa at oregonmetro.gov>
>>>>>     on Tue, 22 Aug 2017 14:39:50 +0000 writes:

    >> Hello, I've noticed the following error using repeat{} / break in R 3.4.1 running on Windows 10 and Windows Server 2008 (both 64-bit environments).
    >> When running a repeat function, the break command causes an error message if the repeat command refers to code within a file, but does not produce an error if the code is contained within the repeat{} command.

    >> Hello, I've noticed the following error using repeat{} / break in R 3.4.1 running on Windows 10 and Windows Server 2008 (both 64-bit environments).
    >> 
    >> When running a repeat function, the break command causes an error message if the repeat command refers to code within a file, but does not produce an error if the code is contained within the repeat{} command.
    >> 
    >> For example, the following code runs fine:
    >> 
    >> x <- 1
    >> y <- 5
    >> 
    >> repeat {
    >> if(x < y) {
    >> print("No Break Dance :-(")
    >> x = x + 1
    >> } else {
    >> print("Break Dance!")
    >> break
    >> }
    >> }
    >> 
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "Break Dance!"
    >> >
    >> 
    >> However, if I take the loop contents of the repeat{} function, and save them to a file (breakTest.R) that contains the following:
    >> 
    >> if(x < y) {
    >> print("No Break Dance :-(")
    >> x = x + 1
    >> } else {
    >> print("Break Dance!")
    >> break
    >> }
    >> 
    >> And then run the following code:
    >> 
    >> x <- 1
    >> y <- 5
    >> 
    >> repeat{
    >> source("./breakTest.R")
    >> }
    >> 
    >> I get the following error:
    >> 
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "No Break Dance :("
    >> [1] "Break Dance!"
    >> Error in eval(ei, envir) : no loop for break/next, jumping to top level
    >> >
    >> 
    >> This was not an issue with previous versions of R that I have used, including 3.3.3.
    >> 
    >> Any suggestions? Is this a known bug with 3.4.1?

    > Thank you, Peter!

    > I can confirm what you are seeing (on Linux) in R version 3.4.0,
    > 3.4.1, and "R devel", and also that this had worked w/o a
    > problem in earlier versions of R, where I've looked at
    > R version 3.3.3 and 3.2.5.

    > I do think this is a bug, but it was not known till now.

    > For ease of use, I attach the two R files to easily reproduce.
    > Note I use  writeLines() instead of print() as its output is "nicer".

    > Best regards,
    > Martin Maechler, ETH Zurich

Trying again with the two attachment.  Yes, I of all people (!!)
should know that they must have an allowed MIME type; in this
case  text/plain !

Martin

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