| package jp.ac.kobe_u.cs.prolog.builtin; |
| import jp.ac.kobe_u.cs.prolog.lang.*; |
| /** |
| * <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 { |
| static SymbolTerm SYM_DOT = SymbolTerm.makeSymbol("."); |
| 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() {} |
| |
| public void setArgument(Term[] args, Predicate cont){ |
| arg1 = args[0]; |
| arg2 = args[1]; |
| arg3 = args[2]; |
| this.cont = cont; |
| } |
| |
| public int arity() { return 3; } |
| public String toString() { return "functor(" + arg1 + "," + arg2 + "," + arg3 + ")"; } |
| |
| 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; |
| } |
| } |