| package com.googlecode.prolog_cafe.builtin; |
| import com.googlecode.prolog_cafe.lang.*; |
| /** |
| * <code>atom_codes/2</code><br> |
| * @author Mutsunori Banbara (banbara@kobe-u.ac.jp) |
| * @author Naoyuki Tamura (tamura@kobe-u.ac.jp) |
| * @version 1.1 |
| */ |
| public class PRED_atom_codes_2 extends Predicate.P2 { |
| public PRED_atom_codes_2(Term a1, Term a2, Operation cont) { |
| arg1 = a1; |
| arg2 = a2; |
| this.cont = cont; |
| } |
| |
| public Operation exec(Prolog engine) { |
| engine.setB0(); |
| Term a1, a2; |
| a1 = arg1; |
| a2 = arg2; |
| |
| a1 = a1.dereference(); |
| a2 = a2.dereference(); |
| if (a1.isVariable()) { // atom_codes(-Atom, +CharCodeList) |
| StringBuffer sb = new StringBuffer(); |
| Term x = a2; |
| while(! x.isNil()) { |
| if (x.isVariable()) |
| throw new PInstantiationException(this, 2); |
| if (! x.isList()) |
| throw new IllegalTypeException(this, 2, "list", a2); |
| Term car = ((ListTerm)x).car().dereference(); |
| if (car.isVariable()) |
| throw new PInstantiationException(this, 2); |
| if (! car.isInteger()) |
| throw new RepresentationException(this, 2, "character_code"); |
| // car is an integer |
| int i = ((IntegerTerm)car).intValue(); |
| if (! Character.isDefined((char)i)) |
| throw new RepresentationException(this, 2, "character_code"); |
| sb.append((char)i); |
| x = ((ListTerm)x).cdr().dereference(); |
| } |
| if (! a1.unify(SymbolTerm.create(sb.toString()), engine.trail)) |
| return engine.fail(); |
| return cont; |
| } else { // atom_codes(+Atom, ?CharCodeList) |
| if (! a1.isSymbol()) |
| throw new IllegalTypeException(this, 1, "atom", a1); |
| char[] chars = ((SymbolTerm)a1).name().toCharArray(); |
| Term x = Prolog.Nil; |
| for (int i=chars.length; i>0; i--) { |
| x = new ListTerm(new IntegerTerm((int)chars[i-1]), x); |
| } |
| if(! a2.unify(x, engine.trail)) |
| return engine.fail(); |
| return cont; |
| } |
| } |
| } |