[R] try-error in batch and interactive mode

[Uwe Ligges]

Jun Yan wrote:
> 
> I have a tiny R script performing two tasks, the first one of which may
> contain error.
> 
> mammon(12)% cat z.R
> version
> options(show.error.messages = FALSE)
> try(b <- log("foo"))  ## task 1
> 1 + 2                 ## task 2
> 
> Running in batch mode from a solaries machine, the second task never got
> started; see below:
> 
> mammon(13)% R BATCH --vanilla -q z.R
> mammon(14)% cat z.Rout
> > invisible(options(echo = TRUE))
> > version
>          _
> platform sparc-sun-solaris2.8
> arch     sparc
> os       solaris2.8
> system   sparc, solaris2.8
> status
> major    1
> minor    5.1
> year     2002
> month    06
> day      17
> language R
> > options(show.error.messages = FALSE)
> > try(b <- log("foo"))
> >
> 
> The second task does start if run on a linux machine.
> 
> ludwig(22)% cat z.Rout
> > invisible(options(echo = TRUE))
> > version
>          _
> platform i686-pc-linux-gnu
> arch     i686
> os       linux-gnu
> system   i686, linux-gnu
> status
> major    1
> minor    5.1
> year     2002
> month    06
> day      17
> language R
> > options(show.error.messages = FALSE)
> > try(b <- log("foo"))
> > 1 + 2
> [1] 3
> > proc.time()
> [1] 0.87 0.07 0.90 0.00 0.00
> >
> 
> The same code works well if pasted into an interactive R window.

It's not easy to test that, is it?
The next expressions will be evaluated anyway -- with or without a
working try() around it.


> I wonder what is causing the problem on solaries. I need to run a program
> on solaries because the program calls an executable only available for
> solaries.


For me it looks like a bug. 
I am not very sure, particularly since it is there since at least
R-1.1.1, which is the oldest running R version I have got on our Solaris
system, and nobody reported anything like this (nothing similar in the
database). 


Regularly you would write a function such as 

  testit <- function(){
    version
    options(show.error.messages = FALSE)
    try(b <- log("foo"))  ## task 1
    1 + 2                 ## task 2
  }

  testit()

which works in a batch file and is at least a workaround.

Uwe Ligges
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