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

[Tomas Kalibera]

It is a bug in the byte-code compiler. I will fix
Tomas

On 08/23/2017 09:22 AM, Lionel Henry wrote:
> I don't think that's a bug. source() uses eval(), and eval() creates a
> new function-like context frame. In a way expecting `break` to work
> inside source() is like expecting `break` to cross stack frames:
>
>      my_break <- function() break
>      repeat(my_break())
>
> Lionel
>
>
>> On 23 août 2017, at 09:17, Martin Maechler <maechler at stat.math.ethz.ch> wrote:
>>
>>>>>>> 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
>>
>> ## see ./break-source_R341.R
>> if(x < y) {
>>   writeLines("No Break Dance :-(")
>>   x <- x + 1
>> } else {
>>   writeLines("Break Dance!")
>>   break
>> }
>> ## From: Peter Bosa <Peter.Bosa at oregonmetro.gov>
>> ## To: "R-devel at r-project.org" <R-devel at r-project.org>
>> ## Subject: [Rd] Possible repeat{} / break function bug in R 3.4.1
>> ## Date: Tue, 22 Aug 2017 14:39:50 +0000
>>
>> ## 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) {
>>     writeLines("No Break Dance :-(")
>>     x <- x + 1
>>   } else {
>>     writeLines("Break Dance!")
>>     break
>>   }
>> }
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## 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:
>> ##                 ^^^^^^^^^^^
>> ##                __SEE THAT FILE__
>> ## if(x < y) {
>> ##   writeLines("No Break Dance :-(")
>> ##   x = x + 1
>> ## } else {
>> ##   writeLines("Break Dance!")
>> ##   break
>> ## }
>>
>> ## And then run the following code:
>>
>> x <- 1
>> y <- 5
>> repeat{
>>   source("./breakTest.R")
>> }
>> cat("successfully finished\n")
>>
>> ## I get the following error:
>>
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## No Break Dance :(
>> ## 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.
>>
>> ## MM: It does work in R 3.3.3, indeed
>> ## --  it fails in R 3.4.0 and later
>>
>>
>> ## Any suggestions? Is this a known bug with 3.4.1?
>>
>> ## Cheers-
>> ## Peter
>>
>>
>> ## ----------------------------------------------------------------
>> ## peter bosa
>> ## metro
>> ## modeling services
>> ## 600 ne grand ave
>> ## portland, or  97232
>>
>> ## peter.bosa at oregonmetro.gov<mailto:peter.bosa at oregonmetro.gov>
>> ## 503.797.1771
>>
>> ## metro | making a great place
>> ## www.oregonmetro.gov
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel