SmartInt

// Mixing standard signed and unsigned types is dangerous, but...
int ba = -1;
uint bb = 0;
assert(ba > bb);

auto bc = ba + bb;
assert(is(typeof(bc) == uint));
assert(bc == 4294967295u);

// ...with SmartInt, mixed signed/unsigned operations "just work":
import checkedint.throws : SmartInt; // use IntFlagPolicy.throws

SmartInt!int ma = -1;
SmartInt!uint mb = 0;
assert(ma < mb);

auto mc = ma + mb;
assert(is(typeof(mc) == SmartInt!int));
assert(mc != 4294967295u);
assert(mc == -1);

// When IntFlagPolicy.throws is used, failed SmartInt operations will throw a CheckedIntException.
import checkedint.throws : SmartInt;

SmartInt!uint ma = 1;
SmartInt!uint mb = 0;

bool overflow = false;
try
{
    SmartInt!uint mc = mb - ma;
    assert(false);
}
catch(CheckedIntException e)
{
    assert(e.intFlags == IntFlag.negOver);
    overflow = true;
}
assert(overflow);

bool div0 = false;
try
{
    // With standard integers, this would crash the program with an unrecoverable FPE...
    SmartInt!uint mc = ma / mb;
    assert(false);
}
catch(CheckedIntException e)
{
    // ...but with SmartInt, it just throws a normal Exception.
    assert(e.intFlags == IntFlag.div0);
    div0 = true;
}
assert(div0);

// When IntFlagPolicy.noex is used, failed SmartInt operations set one or more bits in IntFlags.local.
import checkedint.noex : SmartInt;

SmartInt!uint ma = 1;
SmartInt!uint mb = 0;
SmartInt!uint mc;

mc = mb - ma;
assert(IntFlags.local == IntFlag.negOver);

// With standard integers, this would crash the program with an unrecoverable FPE...
mc = ma / mb;
// ...but with SmartInt, it just sets a bit in IntFlags.local.
assert(IntFlags.local & IntFlag.div0);

// Each flag will remain set until cleared:
assert(IntFlags.local.clear() == (IntFlag.negOver | IntFlag.div0));
assert(!IntFlags.local);