🚀 go-pugleaf

Someone asked about TI's PC Scheme.  I've used it a fair amount (i.e.,
ported one of our research programs to it in order to run it on
laptops, random hacking), and it is excellent lisp for that class of
machines.  I rountinely run it on old, obsolete COMPAQ Pluses (8086)
as well as snappier machines, and it does reasonable well.  Some features:

SPEED: Incremental byte-code compiler, not interpreter, at top level.
Probably a bit slower on reading, but alot faster on execution.

COMPILER: You can compile files and produce "fasload" files, in the
style of MACLISP.  (In fact, a good way to program in PC-Scheme if
you've been around a while is to close your eyes and say, "It's 1975,
what would I do next?")

ENVIRONMENT: Again, about as well as you can do on this class of
hardware.  While TI succumbed to the Lisp-implementor's macho and
built their editor in Scheme, it is acceptable for very small files.
For serious programs, buy Software Carousel and use your own favorite
programming editor (I like Final Word, with appropriate macros for
paren balancing).  Reasonable window system if you want to build fancy
interfaces.  Reasonable trace system.

QUALITY: I haven't found any bugs, which is actually a little
surprising since I tend to break Lisp systems.  Only one or two pieces
of brain-damage in the design (i.e., the attempt to clone DEFSTRUCT,
which has the default printing of a structure be a list of its
components (the CL default) but NOT providing the ability to define a
printing function (which CL does).  This makes it useless for building
any descriptions involving backpointers, in other words, pretty
useless.)

If you want to hack Lisp on PC's and you can live without Common Lisp
then I think TI's PC-Scheme is the lisp to get.  (I don't think you
can really live WITH Common Lisp on anything smaller than a 386,
personally.  And I have my doubts about them...)  Even if you really
long for Common Lisp, you can do surprisingly well by defining
DEFSTRUCT, SETF, and a package for faking keyword definitions.