o fix new() bug pointed out by "Paul" at inline@perl.org
o allow assignment to _HASH & _ARRAY (but not _KEYS)
o change names of _HASH, _ARRAY, and _KEYS (to what?)
o add a _TIEHASH accessor?
o allow nesting of structures which aren't _pointers_
o enum support?
o #define support?
o type checking in accessors