Interlisp was the so-called "west coast" Lisp that emphasized an interactive programming environment and in retrospect looks more like a hybrid between Smalltalk and Lisp than modern Lisp implementations. It was developed at PARC for a while. I don't know if there was cross-pollination between Interlisp and Smalltalk or if the similarity was a zeitgeist thing.

This article talks about the design values of the system and communicates the flavour of what a Smalltalkish Lisp would have been like.

As someone who's only read about this, I'd be interested in hearing from people who actually used it.

It's very much like an early version of Smalltalk: monochrome, with an early-80s style GUI. There's a popup main menu with a surprising number of options, plus several editors, debugging tools, and a Smalltalk-like 'Transcript' window (for output). The system is image-based, so the running image could be stopped and restarted, even from a different machine.

More intriguingly - and again, analogous to Smalltalk - Interlisp is more than just another Lisp dialect: it's a complete operating system running atop a Lisp VM, with Lisp as the system language, from top to bottom. Awesome!

By today's standards, it's clunky (as one would expect), but if development had continued, I suspect the comparison to Symbolics Genera would be the analog of comparing a GUI desktop environment to a console-based one. Considering the richness of modern environments (have you seen Pharo or Squeak?), that could've been a seriously cool Lisp development platform...

Incidentally, ParEdit is based on Interlisp's SEdit (in Taylor Campbell's words, 'a real structure editor, not a cheesy imitation like paredit').

> I suspect the comparison to Symbolics Genera would be the analog of comparing a GUI desktop environment to a console-based one

Huh? The MIT-class Lisp Machines also had GUIs from the beginning. Clunky by modern standards, as you say, but definitely graphical.

Maybe I just don't get what analogy you're trying to draw.

Yes, you're right - I was mistaken (I was thinking of Slime/Emacs). Genera had a proper hierarchical window system - screenshots just don't do it justice!

From 1986-88, I worked for Xerox AI Systems, the group that commercialized Interlisp-D. We(my personal contribution was relatively small) added Common Lisp to the system, along with SEdit, a friendlier-than-DEdit structure editor.

Interlisp-D went against the grain of most other Lisp implementations at the time:

* Byte-coded implementation interpreted in micro-code, for very compact compiled code (vs. RISC machines' larger, faster code)

* Tuned for interactive performance (vs. tuned for Gabriel benchmark performance)

* Managed code and structure editing (vs. text files and emacs)

In late 1988, Xerox tried to spin the Lisp/AI business out into a separate company named enVos. Envos crashed almost immediately:

http://www.the-scientist.com/?articles.view/articleNo/10590/...

Medley, the last release from enVos, hung on as a commercial product from Venue:

http://top2bottom.net/medley.html

Much of that is actually a decade or more older. It was then called BBN Lisp. The BBN team then went to Xerox PARC. There they also moved this Lisp onto the new personal workstations.

http://www.softwarepreservation.org/projects/LISP/bbnlisp

This gives the impression what they had in 1971:

http://www.softwarepreservation.org/projects/LISP/bbnlisp/Te...

I got a Xerox 1108 Lisp Machine running Interlisp-D in 1982 and enjoyed it greatly. It had knowledge of code like modern IDEs making code inspection and refactoring easier. Back then, it was like magic.

Now however, I prefer IntelliJ for Clojure and Java, and the similar IDE RubyMine for Ruby development. I think very good IDEs are a spiritual successor to the wonderful programming environment if my 1108.

Nice article. I have a Xerox 6085 "Daybreak" workstation that runs Interlisp.

An emulator exists, that runs on various *nix systems. It used to be available for noncommercial use under here http://www2.parc.com/isl/groups/nltt/medley/ but the links seem dead.

Email me if you want a copy... I also have it set up in a Debian image, ready-to-run.

Is it abandonware or is there still commercial interest in it?