jpl stuff

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1120 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

LGPL/JPL/java/jpl/JPL.java

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+//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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