//tabstop=4
//*****************************************************************************/
// Project: jpl
//
// File: $Id: JPL.java,v 1.1 2004-08-27 20:27:56 vsc Exp $
// Date: $Date: 2004-08-27 20:27:56 $
// Author: Fred Dushin <fadushin@syr.edu>
//
//
// Description:
//
//
// -------------------------------------------------------------------------
// Copyright (c) 2004 Paul Singleton
// Copyright (c) 1998 Fred Dushin
// All rights reserved.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Library Public License for more details.
//*****************************************************************************/
package jpl;
import jpl.fli.Prolog;
//----------------------------------------------------------------------/
// JPL
/**
* The jpl.JPL class contains methods which allow (i) inspection and alteration
* of the "default" initialisation arguments (ii) explicit initialisation
* (iii) discovery of whether the Prolog engine is already initialised,
* and if so, with what arguments.
* The Prolog engine must be initialized
* before any queries are made, but this will happen automatically
* (upon the first call to a Prolog FLI routine) if it has not already
* been done explicitly.
*
* <hr><i>
* Copyright (C) 2004 Paul Singleton<p>
* Copyright (C) 1998 Fred Dushin<p>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.<p>
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library Public License for more details.<p>
* </i><hr>
* @author Fred Dushin <fadushin@syr.edu>
* @version $Revision: 1.1 $
*/
public class JPL {
protected static final boolean DEBUG = false;
protected static boolean modeDontTellMe = true;
//------------------------------------------------------------------/
// setDTMMode
/**
* Sets the global "dont-tell-me" mode (default value: true).
* When 'true', bindings will *not* be returned for any variable (in a Query's goal)
* whose name begins with an underscore character (except for "anonymous" variables,
* i.e. those whose name comprises just the underscore character, whose bindings are never returned).
* When 'false', bindings are returned for *all* variables except anonymous ones;
* this mode may be useful when traditional top-level interpreter behaviour is wanted,
* e.g. in a Java-based Prolog IDE or debugger.<p>
* This method should be regarded as experimental, and may subsequently be deprecated
* in favour of some more general mechanism for setting options, perhaps per-Query and
* per-call as well as globally.
*
* @param dtm new "dont-tell-me" mode value
*/
public static void setDTMMode( boolean dtm){
modeDontTellMe = dtm;
}
//------------------------------------------------------------------/
// getDefaultInitArgs
/**
* Returns, in an array of String, the sequence of command-line
* arguments that would be used if the Prolog engine were to be initialised now.
* Returns null if the Prolog VM has already been initialised (in which
* case the default init args are irrelevant and the actual init args are of interest)<p>
*
* @see jpl.JPL#getActualInitArgs
* @return current default initialisation arguments, or null if already initialised
*/
public static String[] getDefaultInitArgs() {
return Prolog.get_default_init_args();
}
//------------------------------------------------------------------/
// setDefaultInitArgs
/**
* Specifies, in an array of String, the sequence of command-line
* arguments that should be used if the Prolog engine is subsequently initialised.<p>
*
* @param args new default initialization arguments
*/
public static void setDefaultInitArgs(String[] args) {
Prolog.set_default_init_args(args);
}
//------------------------------------------------------------------/
// getActualInitArgs
/**
* Returns, in an array of String, the sequence of command-line
* arguments that were actually used when the Prolog engine was formerly initialised.
*
* This method returns null if the Prolog engine has not yet been initialised,
* and thus may be used to test this condition.
*
* @return actual initialization arguments
*/
public static String[] getActualInitArgs() {
return Prolog.get_actual_init_args();
}
//------------------------------------------------------------------/
// init
/**
* Initializes the Prolog engine, using the String argument
* parameters passed. This method need be called only if you want to both
* (i) initialise the Prolog engine with parameters other than the default ones
* and (ii) force initialisation to occur
* (rather than allow it to occur automatically at the first query).
* For parameter options, consult your local
* Prolog documentation. The parameter values are passed directly
* to initialization routines for the Prolog environment.<p>
*
* This method must be called before making any queries.
*
* @param args Initialization parameter list
*/
public static boolean init(String[] args) {
return Prolog.set_default_init_args(args) && init();
}
//------------------------------------------------------------------/
// init
/**
* Initialises the Prolog engine using the current default initialisation parameters,
* and returns 'true' (or 'false' if already initialised).
*/
public static boolean init() {
return Prolog.initialise();
}
//------------------------------------------------------------------/
// halt
/**
* Terminates the Prolog session.<p>
*
* <b>Note.</b> This method calls the FLI halt() method with a
* status of 0, but the halt method currently is a no-op in SWI.
* @deprecated
*/
public static void halt() {
Prolog.halt(0);
}
// a static reference to the current Version
private static final Version version_ = new Version();
//------------------------------------------------------------------/
// version
/**
* Returns (as a Version) an identification of this version of JPL.
* @return the running version of JPL.
*/
public static Version version() {
return version_;
}
//------------------------------------------------------------------/
// version_string
/**
* Returns a String (eg "3.0.0-alpha") identifying this version of JPL.
* @return a String (eg "3.0.0-alpha") identifying this version of JPL.
*/
public static String version_string() {
return version_.major + "." + version_.minor + "." + version_.patch + "-" + version_.status;
}
public static void main(String[] args) {
System.out.println(version_string());
}
}
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