[R-gui] Small annoyance while interacting with R

Hello,

I'm trying to write some program in Ruby to interact with the R console but it
doesn't work : in short, I can connect R standard input, output and error and
retrieve correct calculations for correct inputs, but as soon as R writes
something to the standard error, the program exits.

For example

for

stdin : "3 + 3;"
stdout : ">3+3\n" "6\n"

but for
stdin : "a;"
stdout : "Error : object not found\n" "Execution finished"

It doesn't say that when used with the normal shell.
The same program works perfectly with the simple calculator bc. Does anyone
knows of this particularity ?

Pablo

I'm trying to write some program in Ruby to interact with the R console but
it doesn't work : in short, I can connect R standard input, output and
error and retrieve correct calculations for correct inputs, but as soon as
R writes something to the standard error, the program exits.

Hi,

I'm trying to write some program in Ruby to interact with the R console but
it doesn't work : in short, I can connect R standard input, output and
error and retrieve correct calculations for correct inputs, but as soon as
R writes something to the standard error, the program exits.

this is from memory, and may not be entirely correct, but roughly it's this:
If R notices it is not connected to a PTY, it goes into scripting/batch mode 
(i.e. interactive () == FALSE). This means, it will exit on any error. As far 
as I recall, this behavior cannot be changed, or at least not easily so.
A way to work around this is to embed R:
http://stat.ethz.ch/R-manual/R-devel/doc/manual/R-exts.html#Linking-GUIs-and-other-front_002dends-to-R
then set R_ConsoleFile = NULL, and override ptr_R_WriteConsole (Linux) or 
Rd->WriteConsole to point to your own function to handle output.
Several slightly different solutions are possible, but the key is to avoid 
having R go into batch mode.

Regards
Thomas Friedrichsmeier

Hi,

I'm trying to write some program in Ruby to interact with the R console but
it doesn't work : in short, I can connect R standard input, output and
error and retrieve correct calculations for correct inputs, but as soon as
R writes something to the standard error, the program exits.

this is from memory, and may not be entirely correct, but roughly it's this:
If R notices it is not connected to a PTY, it goes into scripting/batch mode 
(i.e. interactive () == FALSE). This means, it will exit on any error. As far 
as I recall, this behavior cannot be changed, or at least not easily so.

On 10/24/2005 11:36 AM, Thomas Friedrichsmeier wrote:

Hi,

I'm trying to write some program in Ruby to interact with the R console but
it doesn't work : in short, I can connect R standard input, output and
error and retrieve correct calculations for correct inputs, but as soon as
R writes something to the standard error, the program exits.

this is from memory, and may not be entirely correct, but roughly it's this:
If R notices it is not connected to a PTY, it goes into 
scripting/batch mode (i.e. interactive () == FALSE). This means, it 
will exit on any error. As far as I recall, this behavior cannot be 
changed, or at least not easily so.

It can be easily changed (at least on some platforms), but the method 
is not obvious.  In Windows if Rterm.exe is started with command line 
option --ess it acts pretty much the way Pablo wants.  This is 
documented as a Windows-only option; I'm not sure what the method 
would be to achieve the same on other platforms.

Duncan Murdoch

workaround, talk to a C program embedding R. I must admit it is quite a
difficult task for me (I'm an economist) but I will give it a try.

Pablo

PS : my "program" in ruby under Linux was,

require 'open3'
rin,rout,rerr = Open3.popen3('R --vanilla --quiet')
rin.puts("2+4;")
rerr.gets # returns "2+4;\n" "6\n"

Quoting Duncan Murdoch <murdoch at stats.uwo.ca>:

On 10/24/2005 11:36 AM, Thomas Friedrichsmeier wrote:

Hi,

I'm trying to write some program in Ruby to interact with the R
console but
it doesn't work : in short, I can connect R standard input, output and
error and retrieve correct calculations for correct inputs, but as
soon as
R writes something to the standard error, the program exits.

this is from memory, and may not be entirely correct, but roughly it's
this:
If R notices it is not connected to a PTY, it goes into
scripting/batch mode (i.e. interactive () == FALSE). This means, it
will exit on any error. As far as I recall, this behavior cannot be
changed, or at least not easily so.

It can be easily changed (at least on some platforms), but the method
is not obvious.  In Windows if Rterm.exe is started with command line
option --ess it acts pretty much the way Pablo wants.  This is
documented as a Windows-only option; I'm not sure what the method
would be to achieve the same on other platforms.

Duncan Murdoch