public static Term static_transform(Term t, TermSystem system, TransformationContext ctx)
throws TermWareException {
if (t.getArity() != 2) {
throw new AssertException("logical_and must have arity 2");
}
LogHelper.log(system, LogicalAndTransformer.class, "LogicalAnd, t=", t);
Term frs = t.getSubtermAt(0);
Term snd = t.getSubtermAt(1);
Term retval = t;
if (frs.isBoolean() && snd.isBoolean()) {
ctx.setChanged(true);
retval =
system.getInstance().getTermFactory().createBoolean(frs.getBoolean() && snd.getBoolean());
} else if (frs.isBoolean()) {
if (frs.getBoolean()) {
// true && y -> y
ctx.setChanged(true);
retval = snd;
} else {
// false && y -> false
ctx.setChanged(true);
retval = frs;
}
} else if (snd.isBoolean()) {
if (snd.getBoolean()) {
// x && true -> x
ctx.setChanged(true);
retval = frs;
} else {
// x && false -> x
ctx.setChanged(true);
retval = snd;
}
}
LogHelper.log(system, LogicalAndTransformer.class, "return ", retval);
return retval;
}
