NAME

       xpce - Prolog with graphical user interface (GUI)

SYNOPSIS

       xpce prolog-option ...

DESCRIPTION

       XPCE  is  a language independant library for GUI (Graphical User Interfaces).  This manual page discusses
       XPCE/Prolog: the combination of a Prolog environment and XPCE.

       XPCE is an object-oriented engine that can have methods defined in various languages. XPCE has about  150
       predefined  classes  that  deal  mainly with GUI's.  The object engine of XPE is made available to Prolog
       using the following predicates:

   Predicates:
       new(?Ref, +Term)
              Create an XPCE object from Term and bind the object to the reference  Ref.   The  functor-name  of
              Term  describes  the  class  from  which to create an instance.  The arguments of Term are used as
              initialisation arguments for the new object.  If the object was created successfully and Ref is  a
              variable,  Ref  will be unified with the term @<RefNumber>.  If Ref is a term of the form @<Atom>,
              this term will serve as a reference for the new object.

              For example ?- new(@p, picture('Hello World').  Creates  a  graphical  window  object  with  title
              "Hello World".

       send(+Ref, +Selector, +Args...)
              Ref is a reference to an existing XPCE object.  Selector is the name of a (send-)method defined on
              (the class of) this object and Args are terms that describe arguments to be passed to the method.

              send/[2-12]  will  convert  the arguments to XPCE data objects, resolve the procedure (C-function,
              Prolog predicate) implementing the method  and  run  the  implementation.   If  the  execution  is
              successful, send succeeds, otherwise send fails.

              For  example  ?-  send(@p, open, point(400,100)).   opens  the  picture  created above at position
              400,100 on the display.

       get(+Ref, +Selector, +Args ..., -Value)
              Ref is a reference to an existing XPCE object.  Selector is the name of a (get-)method defined  on
              (the  class  of) this object and Args are terms to provide additional arguments.  get/[3-13] works
              similar as send/[2-12] but returns a value rather than succeeding/failing (boolean operation).

              For example get(@p, height, H).  Unifies H with the height of the graphical window.

       free(+Ref)
              If Ref is a reference to an XPCE object,  invoke  send(Ref,  free).   to  the  object.   Otherwise
              succeed silently.

SEE ALSO

       XPCE's web-home at http://www.swi.psy.uva.nl/projects/xpce/

       Jan  Wielemaker and Anjo Anjewierden Programming in XPCE/Prolog, University of Amsterdam, Dept. of Social
       Science and Informatics (SWI).

       Jan  Wielemaker  SWI-Prolog  4.0  Reference  Manual.   Available  from   the   SWI-Prolog   web-home   at
       http://www.swi.psy.uva.nl/projects/SWI-Prolog/

       The online manual system started with ?- manpce.  or ?- user_help on Quintus or SICStus Prolog.

       The XPCE WWW home page: http://swi.psy.uva.nl/projects/xpce/home.html

       xpce-client(1), pl(1)

COPYING

       XPCE  is  distributed  under  the General Public Licence version 2, also known as the GPL-2 licence.  The
       license terms are in the file COPYING or on the GNU website at http://www.gnu.org.

       In a nutshell, you can modify and use XPCE  as  long  as  you  clearly  indicate  changes,  don't  change
       copyright  messages  and  distribute  the complete source of your work with every binary copy or make the
       source in some other form available for free to your users

       Especially if you do not wish to distribute the source of your work you may wish to consider optaining  a
       commercial license.  Please visit the SWI-Prolog home-page for details.

COPYRIGHT

       Copyright (c) 1985-2001 University of Amsterdam.

AUTHOR

       Jan Wielemaker and Anjo Anjewierden

                                                February 7, 2001                                         XPCE(1)