For the Macintosh II to become the primary development and 
testing machine, it would be nice to have a single executable for the
interpreter that runs all ZIP, EZIP, and XZIP games (plus any future
flavors).  This program would also implement a virtual debugger, like
ZDDT.  Size and speed are not expected to be limitations.

    When a game is shipped it would be nice to have a tighter
executable, without superfluous code or the debugger.  Size and speed
on lesser Macintoshes might be a consideration.

    To achieve the first goal:

    () The instruction decoding section can include multiple 
dispatch tables.  This allows for clean migration of opcodes and
detection of illegal operations in context.

    () Individual operators can be shared when possible (e.g. only
one ADD routine is required) and separated into several flavors when
the differences are great enough (e.g. for byte- vs. word-oriented
object operations).

    () Cases of lesser operator differences can be handled by run-time
branching, ZIP20 style (e.g. the version display in VERIFY).

    To achieve the second goal:

    () Conditional compilation/assembly directives can be used
judiciously throughout the source, allowing the shippable version of
a given interpreter to be built based on the state of a handful of
flags.