| package jp.ac.kobe_u.cs.prolog.builtin; |
| import jp.ac.kobe_u.cs.prolog.lang.*; |
| import java.util.Vector; |
| /** |
| * <code>java_conversion/2</code> |
| * @author Mutsunori Banbara (banbara@kobe-u.ac.jp) |
| * @author Naoyuki Tamura (tamura@kobe-u.ac.jp) |
| * @version 1.1 |
| */ |
| public class PRED_java_conversion_2 extends Predicate { |
| Term arg1, arg2; |
| |
| public PRED_java_conversion_2(Term a1, Term a2, Predicate cont) { |
| arg1 = a1; |
| arg2 = a2; |
| this.cont = cont; |
| } |
| public PRED_java_conversion_2() {} |
| |
| public void setArgument(Term[] args, Predicate cont){ |
| arg1 = args[0]; |
| arg2 = args[1]; |
| this.cont = cont; |
| } |
| |
| public int arity() { return 2; } |
| |
| public String toString() { return "java_conversion(" + arg1 + "," + arg2 + ")"; } |
| |
| public Predicate exec(Prolog engine) { |
| engine.setB0(); |
| Term a1, a2; |
| a1 = arg1; |
| a2 = arg2; |
| |
| a1 = a1.dereference(); |
| a2 = a2.dereference(); |
| if (a1.isVariable()) { // a1 = var |
| if (a2.isJavaObject()) { // a1 = var /\ a2 = java |
| ((VariableTerm)a1).bind(inverseConversion(((JavaObjectTerm)a2).object()), engine.trail); |
| } else { // a1 = var /\ a2 = nonjava |
| ((VariableTerm)a1).bind(a2, engine.trail); |
| } |
| } else if (! a2.isVariable()) { // a1 = nonvar /\ a2 = nonvar |
| throw new IllegalTypeException(this, 2, "variable", a2); |
| } else { // a1 = nonvar /\ a2 = var |
| // (a1 = java \/ a1 = str \/ a1 = clo) /\ a2 = var |
| if (a1.isJavaObject() || a1.isStructure() || a1.isClosure()) { |
| ((VariableTerm)a2).bind(a1, engine.trail); |
| } else { // a1 != java /\ a1 != str /\ a1 != clo /\ a2 = var |
| ((VariableTerm)a2).bind(new JavaObjectTerm(a1.toJava()), engine.trail); |
| } |
| } |
| return cont; |
| } |
| |
| protected Term inverseConversion(Object o) { |
| if (o == null) { |
| throw new EvaluationException(this, 2, "undefined"); |
| } else if (o instanceof Byte || |
| o instanceof Short || |
| o instanceof Integer || |
| o instanceof Long) { |
| return new IntegerTerm(((Number)o).intValue()); |
| } else if (o instanceof Float || |
| o instanceof Double) { |
| return new DoubleTerm(((Number)o).doubleValue()); |
| } else if (o instanceof String) { |
| return SymbolTerm.makeSymbol((String) o); |
| } else if (o instanceof Vector) { |
| Vector v = (Vector) o; |
| Term t = Prolog.Nil; |
| for(int i= v.size(); i>0; i--) { |
| t = new ListTerm(inverseConversion(v.elementAt(i-1)), t); |
| } |
| return t; |
| } |
| return new JavaObjectTerm(o); |
| } |
| } |