- The ISO 2022-JP encoder is now static as with all others; this is
slightly slower, but localises the encoder logic to its class
- Indexed encoders now cache pointer tables on first use, yielding
significant performance benefits
- Encoding multiple characters now uses fewer function calls, yielding
moderate performance benefits at the expense of slight complication
The encoder currently operates only on single code points, but will later be
expanded to operate on iterables to construct complete strings. For encodings
other than ISO 2022-JP this is merely a convenience, but the algorithm for
that encoding mandates that encoded strings terminate in a switch to ASCII
mode, which a single-character encoder cannot accomplish by itself.