Object stream = null;
// Char
a2 = a2.dereference();
if (a2.isVariable()) {
throw new PInstantiationException(this, 2);
}
if (!a2.isInteger()) {
try {
a2 = Arithmetic.evaluate(a2);
} catch (BuiltinException e) {
e.goal = this;
e.argNo = 2;
throw e;
}
}
n = ((NumberTerm) a2).intValue();
if (!Character.isDefined(n)) {
throw new RepresentationException(this, 2, "character_code");
}
// 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))