Expression r = rhs.evaluate();
if (l instanceof ANumber && r instanceof ANumber) {
OrderedPair args = Numbers.toSameType(l, r);
return TruthValue.valueOf(((ANumber) args.a()).le((ANumber) args.b()));
} else if (l.equals(Infinity.MINUS_INFINITY) &&
((r instanceof Infinity) || (r instanceof ANumber))) {
return TruthValue.True;
} else if (r.equals(Infinity.PLUS_INFINITY) &&
((l instanceof Infinity) || (l instanceof ANumber))) {