@reduce

macro @reduce(array, identity, #operation)

Apply a reduction/folding operation to an iterable type. This walks along the input array
and applies an `#operation` to each value, returning it to the `identity` (or "accumulator")
base value.

For example:
```c3
int[] my_slice = { 1, 8, 12 };
int folded = array::@reduce(my_slice, 2, fn (i, e) => i * e);
assert(folded == (2 * 1 * 8 * 12));
```

Notice how the given `identity` value started the multiplication chain at 2. When enumerating
`my_slice`, each element is accumulated onto the `identity` value with each sequential iteration.
```
i = 2; // identity value
i *= 1; // my_slice[0]
i *= 8; // my_slice[1]
i *= 12; // my_slice[2]
```

Parameters