====== JPL ======
[[http://www.swi-prolog.org/packages/jpl/|JPL]] is a library using the SWI-Prolog foreign interface and the Java jni interface providing a bidirectional interface between Java and Prolog that can be used to embed Prolog in Java as well as for embedding Java in Prolog. In both setups it provides a reentrant bidirectional interface.



===== Installing SWI-Prolog with JPL in Linux =====

Notice: Based on first-hand experience, the use of standard ''swi-prolog'' packages in Debian-based distributions is **not** recommended, due to the following:
  * ''swi-prolog'' is absent in Debian Etch whatsoever (packages can be found in unstable and testing branches though),
  * JPL is not included in Debian/Ubuntu packages (probably due to licensing issues, see below),
  * the standard package name (''pl'') has been changed to ''swi-prolog''; that is known to break some things, including XPCE.

With the above in mind, the following options are available:
  * use the stable RPM package available at the [[http://www.swi-prolog.org/dl-stable.html|SWI-Prolog download page]] (RPM-based distros only),
  * install from source (coming soon), FIXME
  * [[rpm2deb|convert the RPM package to DEB]] (in this case, rather harmless) or use the converted package,
  * use binary packages compiled from the source (coming soon). FIXME

Alternatively, you can use the repository packages and install JPL as standalone. For now, posts #6 and #7 in [[http://ubuntuforums.org/showthread.php?t=447728|this discussion]] should provide some insight.

===== Installing SWI-Prolog with JPL in Mac OS X =====

Installation and testing instructions for Mac OS X can be found [[macosx|here]].

===== Dependencies =====

DIYers should find [[dependencies|this]] handy.


===== Testing =====

The following can be used to test whether JPL is working properly:

  * go to the ''lib'' directory of your JPL-enabled SWI-Prolog installation:
    * if you're using Linux and installed the RPM package: ''/usr/lib/pl-<version>''
    * if you're a Mac user: ''/opt/local/lib/swipl-<version>''
  * cd to ''doc/packages/examples/jpl/java/Test''
  * delete ''Test.class'' to force re-compilation of the test app
  * launch ''./run.sh''
  * if all goes well, you should get something like this:

  bash-3.2# ./run.sh
  Compiling Test
  
  JPL demo: Test
  
  test 0...% test.pl compiled 0.00 sec, 4,064 bytes
  passed.
  test 1...passed.
  test 2...passed.
  test 3...passed.
  test 4...passed.
  test 5...passed.
  test 6...passed.
  test 7...passed.
  test 8...passed.
  test 9...passed.
  test 10...passed.
  test 11...passed.
  test 101...00004567182904567231901235678312041678321528904567312936890412738905683412794156842736189057340412506823420839420831756240819623751407856239104837562910482956804237195684739158764391584763596579576799passed.

===== Packages =====

The following SWI-Prolog with JPL packages are available:

  * Debian/Ubuntu, converted from original RPMs: {{:prolog:jpl:pl_5.6.54-320_i386.deb|5.6.54}}
  * OS X 10.4 and 10.5 users can get their installers [[http://www.swi-prolog.org/dl-stable.html|here]]

For DIY:
  * //Patches vs. original debian/ubuntu packages// FIXME
  * [[dependencies|build dependencies]]



====== Specs ======
Some insight plus specs:
  * jpl is supposed to work with sun jdk only! (as stated by Jan W.)
  * the main reason [[http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=449437|why jpl is not enabled]] in standard debian/ubuntu is the fact, that sun jdk is not free
  * so compilation of jpl is disabled in debs by a debian patch, BUT removing the patch does not result in a working packages! why?
  * we assume, that the packages built will use the standard sun-jdk packages, as generated by the [[http://packages.debian.org/etch/java-package|java-package for etch]] (and hardy)
  * working with jdk 1.5 is a must!
  * working with jdk 1.6 should also be tested and reported! use [[http://packages.debian.org/lenny/java-package|java-package from lenny]]
  * it should be tested using current swi versions from both [[http://packages.debian.org/lenny/swi-prolog|testing]] and [[http://packages.debian.org/sid/swi-prolog|sid]]!
  * check what changed (java package and swi vers) in intrepid ibex
  * some main problems with jpl include a proper location and config. (paths, env vars) for //jpl.so// and //jpl.jar//
  * I assume we get OS X instructions completely free too :-)
  * in the future we might consider testing with openjdk, icedtea, classpath,gcj, whatever... but not now.

 --- //[[gjn@agh.edu.pl|Grzegorz J. Nalepa]] 2008/07/05 10:44//

Some demo projects to test:
  * [[pl:miw:miw08_ruleruntimeg_2]]
  * [[pl:miw:miw08_prolog_javasockets]]
  * [[pl:miw:miw08_ruleruntimeg]]
  * [[pl:miw:miw08_mindstormsapi]]

 --- //[[gjn@agh.edu.pl|Grzegorz J. Nalepa]] 2008/07/05 11:04//