Message-ID: <5142FAB2.5050004@yahoo.de>
Date: 2013-03-15T10:40:50Z
From: Jannis
Subject: does R read commands from scripts instantanously or seuqently during processing
In-Reply-To: <51424578.8050306@xtra.co.nz>
Dear all,
thanks, Rolf and Jeff, for your replies. The command below runs under
Suse Linux. I guess, hoewever, the phenomena I observed would heappen
under other oprating systems as well. The reason why I asked was that R
produced some error messages that did not really point me to the
direction of the edited script file. These errors were usually something
like:
Error: unexpected symbol in "cess finished."
The line in the script which caused this error is:
print(paste(as.character(Sys.time()), ': Process finished.', sep=''))
This line contains valid R code and would normally not produce an error.
Some testing showed that the error above only happens when I edit the
code of the script while the script is run. So R probably reads in a
script submitted that way seuqently directly while executing the
individual commands. No idea though what happens if i would start the
script via source inside R itself.
Thanks again for your suggestions
Jannis
On 14.03.2013 22:47, Rolf Turner wrote:
> On 03/15/2013 05:13 AM, Jannis wrote:
>> Dear R community,
>>
>>
>> when I source a script into R via:
>>
>>
>> R --slave < scriptname.R
>>
>>
>> is the whole script file read at once during startup or is each
>> indivdual line of code read seqnetially during the execution (i.e.
>> directly before r processes the respective command)? In other words,
>> can I savely edit the scriptname.R file even when an active R process
>> still runs the command above?
>
>
> Experiment. Build a toy script with a loop that never terminates. Set
> it going. Edit the script and change the code so that the loop terminates.
> See what happens.
>
> [It seems to me that nothing happens, so that you *can* "safely" edit
> the script while
> the process runs. But further experimentation would be advisable.]
>
> cheers,
>
> Rolf Turner