/*
* Statement.java
*
* Copyright (C) 2008 Pei Wang
*
* This file is part of Open-NARS.
*
* Open-NARS 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.
*
* Open-NARS 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 Open-NARS. If not, see <http://www.gnu.org/licenses/>.
*/
package nars.language;
import java.nio.CharBuffer;
import java.util.Arrays;
import nars.config.Parameters;
import nars.inference.TemporalRules;
import static nars.inference.TemporalRules.ORDER_NONE;
import nars.io.Symbols.NativeOperator;
import static nars.io.Symbols.NativeOperator.STATEMENT_CLOSER;
import static nars.io.Symbols.NativeOperator.STATEMENT_OPENER;
/**
* A statement is a compound term, consisting of a subject, a predicate, and a
* relation symbol in between. It can be of either first-order or higher-order.
*/
public abstract class Statement extends CompoundTerm {
/**
* Constructor with partial values, called by make
* Subclass constructors should call init after any initialization
*
* @param arg The component list of the term
*/
protected Statement(final Term[] arg) {
super(arg);
}
@Override
protected void init(Term[] t) {
if (t.length!=2)
throw new RuntimeException("Requires 2 terms: " + Arrays.toString(t));
if (t[0]==null)
throw new RuntimeException("Null subject: " + this);
if (t[1]==null)
throw new RuntimeException("Null predicate: " + this);
if (Parameters.DEBUG) {
if (isCommutative()) {
if (t[0].compareTo(t[1])==1) {
throw new RuntimeException("Commutative term requires natural order of subject,predicate: " + Arrays.toString(t));
}
}
}
super.init(t);
}
/**
* Make a Statement from given components, called by the rules
* @return The Statement built
* @param subj The first component
* @param pred The second component
* @param statement A sample statement providing the class type
*/
public static Statement make(final Statement statement, final Term subj, final Term pred) {
if (statement instanceof Inheritance) {
return Inheritance.make(subj, pred);
}
if (statement instanceof Similarity) {
return Similarity.make(subj, pred);
}
if (statement instanceof Implication) {
return Implication.make(subj, pred, statement.getTemporalOrder());
}
if (statement instanceof Equivalence) {
return Equivalence.make(subj, pred, statement.getTemporalOrder());
}
return null;
}
/**
* Make a Statement from String, called by StringParser
*
* @param o The relation String
* @param subject The first component
* @param predicate The second component
* @param memory Reference to the memory
* @return The Statement built
*/
final public static Statement make(final NativeOperator o, final Term subject, final Term predicate, boolean customOrder, int order) {
if(Terms.equalSubTermsInRespectToImageAndProduct(subject, predicate)) {
return null;
}
switch (o) {
case INHERITANCE:
return Inheritance.make(subject, predicate);
case SIMILARITY:
return Similarity.make(subject, predicate);
case INSTANCE:
return Instance.make(subject, predicate);
case PROPERTY:
return Property.make(subject, predicate);
case INSTANCE_PROPERTY:
return InstanceProperty.make(subject, predicate);
case IMPLICATION:
return Implication.make(subject, predicate, customOrder ? order : TemporalRules.ORDER_NONE);
case IMPLICATION_AFTER:
return Implication.make(subject, predicate, customOrder ? order : TemporalRules.ORDER_FORWARD);
case IMPLICATION_BEFORE:
return Implication.make(subject, predicate, customOrder ? order : TemporalRules.ORDER_BACKWARD);
case IMPLICATION_WHEN:
return Implication.make(subject, predicate, customOrder ? order : TemporalRules.ORDER_CONCURRENT);
case EQUIVALENCE:
return Equivalence.make(subject, predicate, customOrder ? order : TemporalRules.ORDER_NONE);
case EQUIVALENCE_AFTER:
return Equivalence.make(subject, predicate, customOrder ? order : TemporalRules.ORDER_FORWARD);
case EQUIVALENCE_WHEN:
return Equivalence.make(subject, predicate, customOrder ? order : TemporalRules.ORDER_CONCURRENT);
}
return null;
}
/**
* Make a Statement from given term, called by the rules
*
* @param order The temporal order of the statement
* @return The Statement built
* @param subj The first component
* @param pred The second component
* @param statement A sample statement providing the class type
* @param memory Reference to the memory
*/
// public static Statement make(final Statement statement, final Term subj, final Term pred, final Memory memory) {
// return make(statement, subj, pred, TemporalRules.ORDER_NONE, memory);
// }
final public static Statement make(NativeOperator op, final Term subj, final Term pred, int order) {
return make(op, subj, pred, true, order);
}
//++ TODO
final public static Statement make(final Statement statement, final Term subj, final Term pred, int order) {
return make(statement.operator(), subj, pred, true, order);
/*
if (invalidStatement(subj, pred)) {
return null;
}
if (statement instanceof Inheritance) {
return Inheritance.make(subj, pred);
}
if (statement instanceof Similarity) {
return Similarity.make(subj, pred);
}
if (statement instanceof Implication) {
return Implication.make(subj, pred, order);
}
if (statement instanceof Equivalence) {
return Equivalence.make(subj, pred, order);
}
throw new RuntimeException("Unrecognized type for Statement.make: " + statement.getClass().getSimpleName() + ", subj=" + subj + ", pred=" + pred + ", order=" + order);
*/
}
/**
* Make a symmetric Statement from given term and temporal
information, called by the rules
*
* @param statement A sample asymmetric statement providing the class type
* @param subj The first component
* @param pred The second component
* @param order The temporal order
* @param memory Reference to the memory
* @return The Statement built
*/
final public static Statement makeSym(final Statement statement, final Term subj, final Term pred, final int order) {
if (statement instanceof Inheritance) {
return Similarity.make(subj, pred);
}
if (statement instanceof Implication) {
return Equivalence.make(subj, pred, order);
}
return null;
}
/**
* Override the default in making the nameStr of the current term from
* existing fields
*
* @return the nameStr of the term
*/
@Override
protected CharSequence makeName() {
return makeStatementName(getSubject(), operator(), getPredicate());
}
/**
* Default method to make the nameStr of an image term from given fields
*
* @param subject The first component
* @param predicate The second component
* @param relation The relation operator
* @return The nameStr of the term
*/
final protected static CharSequence makeStatementNameSB(final Term subject, final NativeOperator relation, final Term predicate) {
final CharSequence subjectName = subject.name();
final CharSequence predicateName = predicate.name();
int length = subjectName.length() + predicateName.length() + relation.toString().length() + 4;
StringBuilder sb = new StringBuilder(length)
.append(STATEMENT_OPENER.ch)
.append(subjectName)
.append(' ').append(relation).append(' ')
.append(predicateName)
.append(STATEMENT_CLOSER.ch);
return sb.toString();
}
final protected static CharSequence makeStatementName(final Term subject, final NativeOperator relation, final Term predicate) {
final CharSequence subjectName = subject.name();
final CharSequence predicateName = predicate.name();
int length = subjectName.length() + predicateName.length() + relation.toString().length() + 4;
CharBuffer cb = CharBuffer.allocate(length);
cb.append(STATEMENT_OPENER.ch);
//Texts.append(cb, subjectName);
cb.append(subjectName);
cb.append(' ').append(relation.toString()).append(' ');
//Texts.append(cb, predicateName);
cb.append(predicateName);
cb.append(STATEMENT_CLOSER.ch);
return cb.compact().toString();
}
/**
* Check the validity of a potential Statement. [To be refined]
* <p>
* @param subject The first component
* @param predicate The second component
* @return Whether The Statement is invalid
*/
final public static boolean invalidStatement(final Term subject, final Term predicate, boolean checkSameTermInPredicateAndSubject) {
if (subject==null || predicate==null) return true;
if (checkSameTermInPredicateAndSubject && subject.equals(predicate)) {
return true;
}
if (checkSameTermInPredicateAndSubject && invalidReflexive(subject, predicate)) {
return true;
}
if (checkSameTermInPredicateAndSubject && invalidReflexive(predicate, subject)) {
return true;
}
if ((subject instanceof Statement) && (predicate instanceof Statement)) {
final Statement s1 = (Statement) subject;
final Statement s2 = (Statement) predicate;
final Term t11 = s1.getSubject();
final Term t22 = s2.getPredicate();
final Term t12 = s1.getPredicate();
final Term t21 = s2.getSubject();
if (t11.equals(t22) && t12.equals(t21)) {
return true;
}
}
return false;
}
final public static boolean invalidStatement(final Term subject, final Term predicate) {
return invalidStatement(subject, predicate, true);
}
/**
* Check if one term is identical to or included in another one, except in a
* reflexive relation
* <p>
* @param t1 The first term
* @param t2 The second term
* @return Whether they cannot be related in a statement
*/
private static boolean invalidReflexive(final Term t1, final Term t2) {
if (!(t1 instanceof CompoundTerm)) {
return false;
}
final CompoundTerm ct1 = (CompoundTerm) t1;
if ((ct1 instanceof ImageExt) || (ct1 instanceof ImageInt)) {
return false;
}
return ct1.containsTerm(t2);
}
public static boolean invalidPair(final Term s1, final Term s2) {
boolean s1Indep = s1.hasVarIndep();
boolean s2Indep = s2.hasVarIndep();
if (s1Indep && !s2Indep) {
return true;
} else if (!s1Indep && s2Indep) {
return true;
}
return false;
}
/**
* Check the validity of a potential Statement. [To be refined]
* <p>
* Minimum requirement: the two terms cannot be the same, or containing each
* other as component
*
* @return Whether The Statement is invalid
*/
public boolean invalid() {
return invalidStatement(getSubject(), getPredicate());
}
/**
* Return the first component of the statement
*
* @return The first component
*/
public Term getSubject() {
return term[0];
}
/**
* Return the second component of the statement
*
* @return The second component
*/
public Term getPredicate() {
return term[1];
}
@Override public abstract Statement clone();
}