This is an extension containing the R3-Alpha VECTOR! datatype code, which has been kept compiling in Ren-C. The key difference is that it is an optional part of the build--so that a core interpreter can be built without VECTOR! or its support code.
Vectors were a largely unused/untested feature of R3-Alpha, the goal of which was to store and process raw packed integers/decimals in a native format, in a more convenient way than using a BINARY!.
See FFI test code, e.g. for calling C's qsort(). The goal is that the vector is laid out in a way that is compatible with C's notions of the datatypes:
- int8_t/uint8_t
- int16_t/uint16_t
- int32_t/uint32_t
- int64_/uint64t
- float
- double
To be on the safe side of strict aliasing, reading these data types out of byte buffers (returned by rebBytes()) and into variables of this type should be done via memcpy() and not direct access to cast pointers to the bytes in that buffer.
Some attempts were made by @giuliolunati to extend the R3-Alpha vector to multiple dimensions. These would be much easier to implement in Ren-C. Contact him if interested.