RE: Java - OutofProcessEclipse and EclipseEngine.rpc()

Hi Lloyd, 

Thanks for your report. 

It is not clear from the Java-ECLiPSe interface chapter of the manual (and
it should be) that it is not conventional to have rpc goal arguments become
instantiated to non-EXDR representable ECLiPSe data types. The 16'8194060
which is mentioned below is actually an example of such a piece of data and
is not a normal ECLiPSe term. Another example is the breal type (which
tripped me up in a similar way recently).

What should happen in this case is that the rpc goal you stated will succeed
as usual but the third argument returned to Java will be null as in the case
of an uninstantiated argument, because no EXDR type matches 16'8194060 more
closely.

It is a bug that execution blocks in the remote
interface/OutOfProcessEclipse case, and this will fixed for a patch release.

Thanks,

josh

Developer, Parc Technologies Limited
josh.singer@parc-technologies.com
http://www.parc-technologies.com

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-----Original Message-----
From: Lloyd Kamara [mailto:l.kamara@ic.ac.uk]
Sent: Wednesday, January 30, 2002 3:49 PM
To: eclipse-bugs@icparc.ic.ac.uk
Subject: Java - OutofProcessEclipse and EclipseEngine.rpc()

I have noticed a possible problem with the OutofProcessEclipse
and EclipseEngine.rpc when running the following code (adapted
from QuickTest.java, included in the distribution):

import com.parctechnologies.eclipse.*;
import java.io.*;
public class QuickTest {
 public static void main(String[] args) throws Exception {
    EclipseEngineOptions eclipseEngineOptions = new 
EclipseEngineOptions();
    EclipseEngine eclipse;
    eclipseEngineOptions.setUseQueues(false);
    eclipse = new OutOfProcessEclipse(eclipseEngineOptions);
    // The problematic line is below
    eclipse.rpc( "recorda( test, a, _ )" );
   ((OutOfProcessEclipse) eclipse).destroy();
  }
}


When running this code, the program appears to block at the
line reading:

eclipse.rpc( "recorda( test, a, X )" );

The code runs to completion if an EmbeddedEclipse is used in
place of the  OutOfProcessEclipse.  It also finishes if recorda/3
is replaced by a corresponding recorda/2 call.  It may be
significant that the call to recorda/3 in the rpc invocation would
return a term including a single quote (e.g. 16'8194060).  Could this
cause communication problems between Java and Eclipse (i.e. term-reading
problems), despite the use of an anonymous variable?  I am using
eclipse 5.3 on a Linux system.

Regards,
	Lloyd Kamara