Carbon.

[Stephen J. Turnbull]

Aidan Kehoe writes:

 > Did you use Pitts Jarvis' port at all? Or was that before you moved
 > to OS X?

Pitts's port was a proof of concept oriented to interesting hackers,
not something that was usable by your typical MacUser.  Specifically,
all the GUI was going to be done from Lisp (note the future tense);
the native Carbon frames were just TTY-in-a-window.  There was a
minimal main menubar, but otherwise none of the comforts of $HOME.

What it did have was a pretty full suite of Lisp bindings for the
Carbon API of that time, plus a generic trap function that allowed
pretty general calls into Mac OS X.

As for attracting more users just to have more users, who do you think
is going to support them?