| package jp.ac.kobe_u.cs.prolog.builtin; |
| import jp.ac.kobe_u.cs.prolog.lang.*; |
| /** |
| * <code>char_code/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_char_code_2 extends Predicate { |
| // static SymbolTerm Nil = SymbolTerm.makeSymbol("[]"); |
| Term arg1, arg2; |
| |
| public PRED_char_code_2(Term a1, Term a2, Predicate cont) { |
| arg1 = a1; |
| arg2 = a2; |
| this.cont = cont; |
| } |
| |
| public PRED_char_code_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 "char_code(" + 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()) { // char_code(-Char, +CharCode) |
| if (a2.isVariable()) { |
| throw new PInstantiationException(this, 2); |
| } else if (! a2.isInteger()) { |
| throw new IllegalTypeException(this, 2, "integer", a2); |
| } |
| int i = ((IntegerTerm)a2).intValue(); |
| if (! Character.isDefined(i)) |
| throw new RepresentationException(this, 2, "character_code"); |
| if (! a1.unify(SymbolTerm.makeSymbol(String.valueOf((char)i)), engine.trail)) |
| return engine.fail(); |
| } else if (a1.isSymbol()) { // char_code(+Char, ?CharCode) |
| String s = ((SymbolTerm)a1).name(); |
| if (s.length() != 1) |
| throw new IllegalTypeException(this, 1, "character", a1); |
| if(! a2.unify(new IntegerTerm((int)s.charAt(0)), engine.trail)) |
| return engine.fail(); |
| } else { |
| return engine.fail(); |
| } |
| return cont; |
| } |
| } |