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Sigma knowledge engineering system is an system for developing, viewing and debugging theories in first
order logic. It works with Knowledge Interchange Format (KIF) and is optimized for the Suggested Upper Merged
Ontology (SUMO) www.ontologyportal.org.
package com.articulate.sigma.semRewrite;
/*
Copyright 2014-2015 IPsoft
Author: Adam Pease [email protected]
This program 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.
This program 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 this program ; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
*/
import java.io.*;
import java.text.ParseException;
import java.util.*;
import com.articulate.sigma.*;
/** *************************************************************
* Rule ::= LHS ==> RHS. Obligatory rewrite
LHS ?=> RHS. Optional rewrite
/- Clause. Permanent, unresourced fact
*
* Values for variables on LHS are unified with variables on the
* RHS
*/
public class Rule {
public CNF cnf;
public enum RuleOp {IMP, OPT, CLAUSE}
public LHS lhs;
public RuleOp operator;
public RHS rhs;
public Literal clause;
public int startLine = -1;
/** ***************************************************************
*/
public String toString() {
StringBuffer sb = new StringBuffer();
if (cnf != null) {
sb.append(cnf.toString());
if (operator == RuleOp.IMP)
sb.append(" ==> ");
if (operator == RuleOp.OPT)
sb.append(" ?=> ");
sb.append(rhs.toString() + ".");
}
else if (operator == RuleOp.CLAUSE)
sb.append("/- " + clause.toString() + ".");
else {
sb.append(lhs.toString());
if (operator == RuleOp.IMP)
sb.append(" ==> ");
if (operator == RuleOp.OPT)
sb.append(" ?=> ");
sb.append(rhs.toString()+ ".");
}
sb.append(" ; line " + startLine);
return sb.toString();
}
/** ***************************************************************
*/
public Rule deepCopy() {
Rule r = new Rule();
if (cnf != null)
r.cnf = cnf.deepCopy();
if (lhs != null)
r.lhs = lhs.deepCopy();
r.operator = operator;
if (rhs != null)
r.rhs = rhs.deepCopy();
if (clause != null)
r.clause = clause.deepCopy();
r.startLine = startLine;
return r;
}
/** ***************************************************************
* We won't know whether it's a fact or a rule until we read the
* first token, so the first token for LHS will always be already
* in st.sval
*/
public static Rule parse(Lexer lex) {
Rule r = new Rule();
r.startLine = lex.linepos();
String errStart = "Parsing error in " + RuleSet.filename;
String errStr = null;
boolean isEOL = false;
try {
if (lex.testTok(Lexer.Clause)) {
r.operator = RuleOp.CLAUSE;
r.clause = Literal.parse(lex,r.startLine);
}
else {
do {
r.lhs = LHS.parse(lex,r.startLine);
if (lex.testTok(Lexer.Comma)) {
lex.next();
LHS newlhs = new LHS();
newlhs.lhs1 = r.lhs;
newlhs.operator = LHS.LHSop.AND;
newlhs.lhs2 = LHS.parse(lex, r.startLine);
r.lhs = newlhs;
}
} while (lex.testTok(Lexer.Comma));
if (lex.testTok(Lexer.Implies))
r.operator = RuleOp.IMP;
else if (lex.testTok(Lexer.OptImplies))
r.operator = RuleOp.OPT;
else {
errStr = (errStart + ": Invalid rule operator '" + lex.look() + "' near line " + r.startLine);
throw new ParseException(errStr, r.startLine);
}
lex.next();
//System.out.println("Info in Rule.parse(): " + lex.look());
r.rhs = RHS.parse(lex,r.startLine);
//System.out.println("Info in Rule.parse(): 2 " + lex.look());
if (!lex.testTok(Lexer.FullStop)) {
errStr = (errStart + ": Invalid end token '" + lex.look() + "' near line " + r.startLine);
throw new ParseException(errStr, r.startLine);
}
lex.next();
}
}
catch (Exception ex) {
String message = ex.getMessage();
System.out.println("Error in RULE.parse(): " + message);
ex.printStackTrace();
}
//System.out.println("Info in Rule.parse(): returning: " + r);
return r;
}
/** ***************************************************************
*/
public static Rule parseString(String s) {
Lexer lex = new Lexer(s);
return parse(lex);
}
/** *************************************************************
* A test method
*/
public static void testParse() {
String s = "+num(?O,?N), +sumo(?C,?O) ==> (instance(?O,Collection), membersType(?O,?C), membersCount(?O,?N)).";
//System.out.println("INFO in Rule.testParse(): " + parseString(s));
//s = "+nsubj(?C2,?X), +amod(?C2,?C), cop(?C2,be*), det(?C2,?D), sumo(?Y,?C), sumo(Human,?X), isInstanceOf(?Y,Nation) ==> (citizen(?X,?Y)).";
//System.out.println("INFO in Rule.testParse(): " + parseString(s));
s = "day(?T,?D), month(?T,?M), year(?T,?Y), StartTime(?V,?T) ==> {(equal (BeginFn (WhenFn ?V)) (DayFn ?D (MonthFn ?M (YearFn ?Y))))}.";
System.out.println("INFO in Rule.testParse(): " + parseString(s));
s = "day(?T,?D), month(?T,?M), year(?T,?Y), StartTime(?V,?T).";
Lexer lex4 = new Lexer(s);
CNF cnf5 = CNF.parseSimple(lex4);
System.out.println("INFO in Rule.testParse(): " + cnf5);
}
/** *************************************************************
* A test method
*/
public static void main (String args[]) {
testParse();
}
}