R help - Mar 2013 - does R read commands from scripts instantanously or seuqently during processing

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?


Thanks for your help
Jannis

Your use of the "<" redirection operator is an operating system
feature, not an R feature. I am not aware of any operating system that that
would function properly in the use case you describe.

It is possible, and common, to construct your input file as a stream as you go.
But a stream is not a file on disk.
---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live
Go...
                                      Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
--------------------------------------------------------------------------- 
Sent from my phone. Please excuse my brevity.

Jannis <bt_jannis at yahoo.de> 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?
>
>
>Thanks for your help
>Jannis
>
>______________________________________________
>R-help at r-project.org mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

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