| package jp.ac.kobe_u.cs.prolog.builtin; |
| import jp.ac.kobe_u.cs.prolog.lang.*; |
| import java.io.*; |
| /** |
| * <code>'$read_token0'/3</code><br> |
| * @author Mutsunori Banbara (banbara@kobe-u.ac.jp) |
| * @author Naoyuki Tamura (tamura@kobe-u.ac.jp) |
| * @version 1.0 |
| * @since 0.7 |
| */ |
| class PRED_$read_token0_3 extends Predicate { |
| Term arg1, arg2, arg3; |
| |
| public PRED_$read_token0_3(Term a1, Term a2, Term a3, Predicate cont){ |
| arg1 = a1; |
| arg2 = a2; |
| arg3 = a3; |
| this.cont = cont; |
| } |
| public PRED_$read_token0_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 "$read_token0(" + arg1 + ", " + arg2 + "," + arg3 + ")"; |
| } |
| |
| /* The a1 must be user, user_input, and |
| java.io.PushbackReader, otherwise fails. */ |
| public Predicate exec(Prolog engine) { |
| engine.setB0(); |
| Term a1, a2, a3; |
| a1 = arg1; |
| a2 = arg2; |
| a3 = arg3; |
| |
| Object stream = null; |
| StringBuffer s; |
| int type; |
| Term token; |
| |
| // S_or_a |
| a1 = a1.dereference(); |
| if (a1.isVariable()) { |
| throw new PInstantiationException(this, 1); |
| } else if (a1.isSymbol()) { |
| if (! engine.getStreamManager().containsKey(a1)) |
| throw new ExistenceException(this, 1, "stream", a1, ""); |
| stream = ((JavaObjectTerm) engine.getStreamManager().get(a1)).object(); |
| } else if (a1.isJavaObject()) { |
| stream = ((JavaObjectTerm) a1).object(); |
| } else { |
| throw new IllegalDomainException(this, 1, "stream_or_alias", a1); |
| } |
| if (! (stream instanceof PushbackReader)) |
| throw new PermissionException(this, "input", "stream", a1, ""); |
| // read token |
| s = new StringBuffer(); |
| try { |
| type = Token.read_token(s, (PushbackReader)stream); |
| switch(type) { |
| case 'I': |
| token = new IntegerTerm(Integer.parseInt(s.toString())); |
| break; |
| case 'D': |
| token = new DoubleTerm(Double.parseDouble(s.toString())); |
| break; |
| case 'S': |
| char[] chars = (s.toString()).toCharArray(); |
| token = Prolog.Nil; |
| for (int i=chars.length; i>0; i--){ |
| token = new ListTerm(new IntegerTerm((int)chars[i-1]), token); |
| } |
| break; |
| default : |
| token = SymbolTerm.makeSymbol(s.toString()); |
| break; |
| } |
| } catch (Exception e) { |
| throw new JavaException(this, 1, e); |
| } |
| if (! a2.unify(new IntegerTerm(type), engine.trail)) |
| return engine.fail(); |
| if (! a3.unify(token, engine.trail)) |
| return engine.fail(); |
| return cont; |
| } |
| } |
| |