package jp.ac.kobe_u.cs.prolog.builtin;
import jp.ac.kobe_u.cs.prolog.lang.IllegalDomainException;
import jp.ac.kobe_u.cs.prolog.lang.IllegalTypeException;
import jp.ac.kobe_u.cs.prolog.lang.IntegerTerm;
import jp.ac.kobe_u.cs.prolog.lang.PInstantiationException;
import jp.ac.kobe_u.cs.prolog.lang.Predicate;
import jp.ac.kobe_u.cs.prolog.lang.Prolog;
import jp.ac.kobe_u.cs.prolog.lang.SymbolTerm;
import jp.ac.kobe_u.cs.prolog.lang.Term;
/**
* <code>atom_lengt/2</code><br>
*
* @author Mutsunori Banbara (banbara@kobe-u.ac.jp)
* @author Naoyuki Tamura (tamura@kobe-u.ac.jp)
* @version 1.0
*/
public class PRED_atom_length_2 extends Predicate {
/**
*
*/
private static final long serialVersionUID = 755838702353504071L;
private Term arg1, arg2;
public PRED_atom_length_2(Term a1, Term a2, Predicate cont) {
arg1 = a1;
arg2 = a2;
this.cont = cont;
}
public PRED_atom_length_2() {
}
@Override
public void setArgument(Term[] args, Predicate cont) {
arg1 = args[0];
arg2 = args[1];
this.cont = cont;
}
@Override
public int arity() {
return 2;
}
@Override
public String toString() {
return "atom_length(" + arg1 + "," + arg2 + ")";
}
@Override
public Predicate exec(Prolog engine) {
engine.setB0();
Term a1, a2;
a1 = arg1;
a2 = arg2;
int length;
a1 = a1.dereference();
a2 = a2.dereference();
if (a1.isVariable()) {
throw new PInstantiationException(this, 1);
}
if (!a1.isSymbol()) {
throw new IllegalTypeException(this, 1, "atom", a1);
}
length = ((SymbolTerm) a1).name().length();
if (a2.isVariable()) {
if (!a2.unify(new IntegerTerm(length), engine.trail)) {
return engine.fail();
}
} else if (a2.isInteger()) {
int n = ((IntegerTerm) a2).intValue();
if (n < 0) {
throw new IllegalDomainException(this, 2, "not_less_than_zero",
a2);
}
if (length != n) {
return engine.fail();
}
} else {
throw new IllegalTypeException(this, 1, "integer", a2);
}
return cont;
}
}