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.ListTerm;
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.StructureTerm;
import jp.ac.kobe_u.cs.prolog.lang.SymbolTerm;
import jp.ac.kobe_u.cs.prolog.lang.Term;
import jp.ac.kobe_u.cs.prolog.lang.VariableTerm;
/**
* <code>functor/3</code><br>
*
* @author Mutsunori Banbara (banbara@kobe-u.ac.jp)
* @author Naoyuki Tamura (tamura@kobe-u.ac.jp)
* @version 1.0
*/
public class PRED_functor_3 extends Predicate {
/**
*
*/
private static final long serialVersionUID = 952017293004597202L;
private final static SymbolTerm SYM_DOT = SymbolTerm.makeSymbol(".");
private Term arg1, arg2, arg3;
public PRED_functor_3(Term a1, Term a2, Term a3, Predicate cont) {
arg1 = a1;
arg2 = a2;
arg3 = a3;
this.cont = cont;
}
public PRED_functor_3() {
}
@Override
public void setArgument(Term[] args, Predicate cont) {
arg1 = args[0];
arg2 = args[1];
arg3 = args[2];
this.cont = cont;
}
@Override
public int arity() {
return 3;
}
@Override
public String toString() {
return "functor(" + arg1 + "," + arg2 + "," + arg3 + ")";
}
@Override
public Predicate exec(Prolog engine) {
engine.setB0();
Term a1, a2, a3;
a1 = arg1;
a2 = arg2;
a3 = arg3;
// functor(?X,+Y,+Z)
a1 = a1.dereference();
if (a1.isVariable()) {
a2 = a2.dereference();
if (a2.isVariable()) {
throw new PInstantiationException(this, 2);
}
if (!a2.isSymbol() && !a2.isNumber() && !a2.isJavaObject()
&& !a2.isClosure()) {
throw new IllegalTypeException(this, 2, "atomic", a2);
}
a3 = a3.dereference();
if (a3.isVariable()) {
throw new PInstantiationException(this, 3);
}
if (!a3.isInteger()) {
throw new IllegalTypeException(this, 3, "integer", a3);
}
int n = ((IntegerTerm) a3).intValue();
if (n < 0) {
throw new IllegalDomainException(this, 3, "not_less_than_zero",
a3);
}
if (n == 0) {
if (!a1.unify(a2, engine.trail)) {
return engine.fail();
}
return cont;
}
if (!a2.isSymbol()) {
throw new IllegalTypeException(this, 2, "atom", a2);
}
if (n == 2 && a2.equals(SYM_DOT)) {
Term t = new ListTerm(new VariableTerm(engine),
new VariableTerm(engine));
if (!a1.unify(t, engine.trail)) {
return engine.fail();
}
return cont;
}
Term[] args = new Term[n];
for (int i = 0; i < n; i++) {
args[i] = new VariableTerm(engine);
}
SymbolTerm sym = SymbolTerm.makeSymbol(((SymbolTerm) a2).name(), n);
if (!a1.unify(new StructureTerm(sym, args), engine.trail)) {
return engine.fail();
}
return cont;
}
// functor(+X,?Y,?Z)
Term functor;
IntegerTerm arity;
if (a1.isSymbol() || a1.isNumber() || a1.isJavaObject()
|| a1.isClosure()) {
functor = a1;
arity = new IntegerTerm(0);
} else if (a1.isList()) {
functor = SYM_DOT;
arity = new IntegerTerm(2);
} else if (a1.isStructure()) {
functor = SymbolTerm.makeSymbol(((StructureTerm) a1).name());
arity = new IntegerTerm(((StructureTerm) a1).arity());
} else {
return engine.fail();
}
if (!a2.unify(functor, engine.trail)) {
return engine.fail();
}
if (!a3.unify(arity, engine.trail)) {
return engine.fail();
}
return cont;
}
}