RawArray method
Allocates an unslotted pointer-of-pointers from a list of value arrays.
Each arrays[i] is converted via rawArrayFunc.
The caller is responsible for freeing the returned pointer.
Implementation
PP RawArray(List<List<X>> arrays) {
final pp = Raw(arrays.length);
for (int i = 0; i < arrays.length; i++) indexSetterFunc(pp, i, rawArrayFunc(arrays[i]));
return pp;
}