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/*
    This file is part of JLog.

    Created by Glendon Holst for Alan Mackworth and the 
    "Computational Intelligence: A Logical Approach" text.
    
    Copyright 1998, 2000, 2002 by University of British Columbia and 
    Alan Mackworth.
    
    This notice must remain in all files which belong to, or are derived 
    from JLog.
    
    Check  or 
     for further information
    about JLog, or to contact the authors.
     
    JLog is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    JLog 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with JLog; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    URLs:  or 
*/
//#########################################################################
//	NaryBuiltinPredicate
//#########################################################################
 
package ubc.cs.JLog.Terms;

import java.lang.*;
import java.util.*;
import ubc.cs.JLog.Foundation.*;
import ubc.cs.JLog.Terms.Goals.*;

abstract public class jNaryBuiltinPredicate extends jBuiltinPredicate
{
 protected int 					arity;
 protected jCompoundTerm 		arguments;

 /**
  * jNaryBuiltinPredicate constructor.
  *
  * @param args 	The arguments for the predicate.  Arity of args must not change after
  *					construction.
  * @param t 		The predicates type (typically TYPE_BUILTINPREDICATE).
  */ 
 public jNaryBuiltinPredicate(jCompoundTerm args,int t)
 {
  arguments = args;
  arity = args.size();
   
  type = t;
 };
  
 public final int 		getArity()
 {
  return arity;
 };

 public final jTerm 		getTermAt(int i)
 {
  return arguments.elementAt(i);
 };

 /**
  * The arugments for this predicate.
  *
  * @return		The arguments of the n-ary predicate as a jCompoundTerm.  
  *				The returned arguments must not be modified by adding or removing terms.
  */
 public final jCompoundTerm 		getArguments()
 {
  return arguments;
 };

 protected int 		compareArguments(iPredicate ipred,boolean first_call,boolean var_equal)
 {
  if (ipred instanceof jNaryBuiltinPredicate)
  {jNaryBuiltinPredicate 		tip = (jNaryBuiltinPredicate) ipred;
   
   return arguments.compare(tip.arguments,true,var_equal);
  }

  return (first_call ? -ipred.compareArguments(this,false,var_equal) : EQUAL);
 };

 protected final boolean 	equivalenceArguments(jBuiltinPredicate pterm,jEquivalenceMapping v)
 {
  if (pterm instanceof jNaryBuiltinPredicate)
  {jNaryBuiltinPredicate 	tterm = (jNaryBuiltinPredicate) pterm;
  
   return arguments.equivalence(tterm,v);
  }
  else
   return false;
 };

 protected final boolean 	unifyArguments(jBuiltinPredicate pterm,jUnifiedVector v)
 {
  if (pterm instanceof jNaryBuiltinPredicate)
  {jNaryBuiltinPredicate 	tterm = (jNaryBuiltinPredicate) pterm;
  
   return arguments.unify(tterm,v);
  }
  else
   return false;
 };
 
 public void 		registerVariables(jVariableVector v)
 {
  arguments.registerVariables(v);
 };

 public void 		enumerateVariables(jVariableVector v,boolean all)
 {
  arguments.enumerateVariables(v,all);
 };

 public void 		registerUnboundVariables(jUnifiedVector v)
 {
  arguments.registerUnboundVariables(v);
 };

 public boolean 	prove(jNaryBuiltinPredicateGoal bg)
 {
  throw new UnimplementedPredicateProveMethodException(); 
 };

 public void 		addGoals(jGoal g,jVariable[] vars,iGoalStack goals)
 {
  goals.push(new jNaryBuiltinPredicateGoal(this,(jCompoundTerm) arguments.duplicate(vars)));
 }; 

 public void 		addGoals(jGoal g,iGoalStack goals)
 {
  goals.push(new jNaryBuiltinPredicateGoal(this,arguments));
 }; 

 // since nary predicates have variables, they should be able to duplicate themselves
 // this version of duplicate only requires subclasses to create themselves.
 abstract protected jNaryBuiltinPredicate 	duplicate(jCompoundTerm args);

 public jTerm 		duplicate(jVariable[] vars)
 {
  return duplicate((jCompoundTerm) arguments.duplicate(vars)); 
 };

 public jTerm 		copy(jVariableRegistry vars)
 {
  return duplicate((jCompoundTerm) arguments.copy(vars));
 };

 public void 		consult(jKnowledgeBase kb)
 {
  arguments.consult(kb);
 };
 
 public void 		consultReset()
 {
  arguments.consultReset();
 };
 
 public boolean 	isConsultNeeded()
 {
  return true;
 };

 public String 		toString(boolean usename)
 {
  return (arguments.size() > 0 ? getName() + arguments.toString(usename) : getName());
 };
};