boolean constfolding(int op, expdesc e1, expdesc e2) {
LuaValue v1, v2, r;
if (!e1.isnumeral() || !e2.isnumeral()) return false;
if ((op == OP_DIV || op == OP_MOD) && e2.u.nval().eq_b(LuaValue.ZERO))
return false; /* do not attempt to divide by 0 */
v1 = e1.u.nval();
v2 = e2.u.nval();
switch (op) {
case OP_ADD:
r = v1.add(v2);
break;
case OP_SUB:
r = v1.sub(v2);
break;
case OP_MUL:
r = v1.mul(v2);
break;
case OP_DIV:
r = v1.div(v2);
break;
case OP_MOD:
r = v1.mod(v2);
break;
case OP_POW:
r = v1.pow(v2);
break;
case OP_UNM:
r = v1.neg();
break;
case OP_LEN:
// r = v1.len();
// break;
return false; /* no constant folding for 'len' */
default:
_assert(false);
r = null;
break;
}
if (Double.isNaN(r.todouble())) return false; /* do not attempt to produce NaN */
e1.u.setNval(r);
return true;
}
