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The Medley Interlisp Project
@interlisp.org
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Official account of the open source project to preserve, revive, and modernize Medley Interlisp. This extensible graphical operating and programming environment has roots in Xerox's Palo Alto Research Center (PARC).

https://interlisp.org
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interlisp.org
The Medley Interlisp Project @interlisp.org · Dec 12
Hello from the Medley Interlisp Project! We revive and modernize the Medley Interlisp extensible graphical operating and programming environment created at Xerox PARC.

interlisp.org

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Screenshot of the black and white desktop of a 1980s graphical workstation environment. The desktop has a gray background pattern and several windows with a white background and a title bar with white text on a black background. The windows display text, bitmaps, graphs, icons, sketches, and other graphical documents and elements.
interlisp.org
In Interlisp PUSH and POP manipulate stacks represented as lists and work like the corresponding Common Lisp macros, but PUSH swaps the order of the arguments.

interlisp.org/documentatio...

#interlisp #CommonLisp #lisp
Screenshot of a portion of the black and white desktop of a 1980s graphical workstation environment. The desktop has a grey background pattern and one window with a white background and a title bar with white text on a black background. The window is a Lisp REPL where the following expressions are evaluated, output printed, and values returned: 2/5_ (SETQ STACK '()) NIL 2/6_ (PUSH STACK 1) (1) 2/7_ (PUSH STACK 2) (2 1) 2/8_ (PUSH STACK 3) (3 2 1) 2/9_ (PUSH STACK 4) (4 3 2 1) 2/10_ (PUSH STACK 5) (5 4 3 2 1) 2/11_ (POP STACK) 5 2/12_ (POP STACK) 4 2/13_ STACK (3 2 1)
January 11, 2026 at 10:26 AM
interlisp.org
Published in 1978, this paper by Erik Sandewall is one of the best introductions to the Interlisp environment and development style. It doesn't cover the graphical Interlisp-D system but the material still applies to Medley Interlisp.

dl.acm.org/doi/abs/10.1...

#interlisp #lisp
Programming in an Interactive Environment: the ``Lisp'' Experience | ACM Computing Surveys
dl.acm.org
January 8, 2026 at 9:47 AM
interlisp.org
On November 16, 2023 Steve Kaisler gave the talk “Software Archaeology: The Medley Interlisp Modernisation Project” at a London event of the Computer Conservation Society.

www.youtube.com/watch?v=VcRs...

#interlisp #lisp #retrocomputing
Software Archaeology: The Medley Interlisp Modernisation Project
YouTube video by Computer Conservation Society
www.youtube.com
January 5, 2026 at 11:03 AM
interlisp.org
The Software Preservation Group at the Computer History Museum compiled a list and bibliography of Interlisp implementations. Did you know that Interlisp also ran on IBM 360/370 mainframes?

softwarepreservation.computerhistory.org/LISP/interli...

#interlisp #lisp #retrocomputing
Interlisp family
softwarepreservation.computerhistory.org
January 2, 2026 at 9:43 AM
interlisp.org
In 1965 Peter Deutsch wrote a structure editor for LISP 1.5 which Daniel Bobrow and Warren Teitelman extended and ported to BBN Lisp. It eventually became the Interlisp structure editor.

softwarepreservation.computerhistory.org/LISP/bbnlisp...

#interlisp #lisp #editor #retrocomputing
softwarepreservation.computerhistory.org
December 30, 2025 at 10:25 AM
interlisp.org
A demonstration of defining a Lisp function with the SEdit structure editor of an old version of Medley Interlisp.

www.youtube.com/watch?v=2qsm...

#interlisp #lisp #editor
Lisp Editing in the 80s - Interlisp SEdit
YouTube video by thoughtupquick
www.youtube.com
December 27, 2025 at 12:24 PM
interlisp.org
An example of one way of defining, expanding, and calling an Interlisp macro similar to WHEN of Common Lisp. Macro definitions are represented by lists stored on the property list of a symbol. Here ARGS is bound to the CDR of the calling form.

#interlisp #lisp
Screenshot of a portion of the black and white desktop of a 1980s graphical workstation environment. The desktop has a gray background pattern and one window with a white background and a title bar with white text on a black background. The window is a Lisp REPL where the following expressions are evaluated, output printed, and values returned: 2/4_ (PUTPROP 'WHEN 'MACRO '(ARGS (LIST 'COND (CONS (CAR ARGS) (CDR ARGS))))) (ARGS (LIST (QUOTE COND) (CONS (CAR ARGS) (CDR ARGS)))) 2/5_ (GETPROP 'WHEN 'MACRO) (ARGS (LIST (QUOTE COND) (CONS (CAR ARGS) (CDR ARGS)))) 2/6_ (SETQ FOO 3) 3 2/7_ (EXPANDMACRO '(WHEN (GREATERP FOO 2) (PRINT "Greater.") T)) (COND ((GREATERP FOO 2) (PRINT "Greater.") T)) NIL 2/8_ (WHEN (GREATERP FOO 2) (PRINT "Greater.") T) "Greater." T
December 22, 2025 at 9:29 AM
interlisp.org
Spy is the statistical profiler of Medley Interlisp. The tool periodically interrupts the running program to sample the functions in the current call stack and displays the data.

files.interlisp.org/medley/libra...

#interlisp #profiling #lisp
files.interlisp.org
December 19, 2025 at 10:59 AM
interlisp.org
Evaluate (INSPECTCODE 'FN), where FN is an Interlisp function name, to disassemble the compiled function and see the opcodes of Maiko, the Medley Interlisp virtual machine. This example also shows the corresponding source of the function.
Screenshot of the black and white desktop of a 1980s graphical workstation environment. The desktop has a gray background pattern and several windows with a white background and a title bar with white text on a black background. One of the two main windows shows the disassembly of the compiled Interlisp function APPEND with the opcodes of the Medley Interlisp virtual machine. The other window is an editor that shows the Interlisp code of the APPEND function.
December 16, 2025 at 9:56 AM
interlisp.org
Episode 17 of the Netstack.FM podcast features an interview with Larry Masinter on Interlisp and the Medley project, the PARC environment, the early history of the web, standards and protocols, and more.

netstack.fm#episode-17

www.youtube.com/watch?v=JZ7E...

#retrocomputing #interlisp #web #ietf
Netstack.FM — A Podcast About Networking and Rust
Interviews, monologues, and deep dives into Rust and modern networking systems.
netstack.fm
December 13, 2025 at 9:38 AM
interlisp.org
The canonical capitalization of Interlisp is "Interlisp" or "INTERLISP". InterLisp is much less common in the documentation of and literature on the system.

#interlisp #lisp
December 10, 2025 at 10:37 AM
interlisp.org
Ryan Burnside's notes on Advent on Code with Medley Interlisp:

groups.google.com/g/lispcore/c...
Advent of Code starts soon
groups.google.com
December 7, 2025 at 11:11 AM
interlisp.org
Ryan Burnside is doing Advent of Code 2025 in Common Lisp on Medley Interlisp.

www.linkedin.com/feed/update/...

#AdventOfCode #interlisp #CommonLisp
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December 7, 2025 at 11:09 AM
interlisp.org
To move most windows on Medley Interlisp click the title bar and drag, to resize click a lower corner and drag. These recent modernization features are in addition to the corresponding Move and Reshape items of the classic right-click title bar menu.

#interlisp #gui #lisp
December 4, 2025 at 9:57 AM
interlisp.org
We published Medley Interlisp for the Newcomer, a new primer that eases users into the Interlisp environment. It covers the user interface, programming, graphics, and more.

The primer is a living document and we welcome your feedback.

primer.interlisp.org

#interlisp #lisp #retrocomputing
Before You Begin | Medley Interlisp for the Newcomer
primer.interlisp.org
December 1, 2025 at 10:04 AM
interlisp.org
Interlisp uses the "spaghetti stack", an access and control mechanism more general than a linear stack. Control constructs such as generators, coroutines, and possibilities lists are applications of the spaghetti stack.

interlisp.org/documentatio...

#interlisp #retrocomputing
interlisp.org
November 28, 2025 at 9:22 PM
interlisp.org
In the 1980s Interlisp-D came with a read-only remote desktop client for monitoring networked Lisp workstations, like in the screenshot. Medley Interlisp still includes the code which doesn't currently work.

files.interlisp.org/medley/lispu...

#interlisp #RemoteDesktop #retrocomputing
Screenshot of the black and white desktop of a 1980s graphical workstation environment. The desktop has a gray background pattern and some windows with a white background and a title bar with white text on a black background. The screen shows a scaled down version of the entire remote screen of an Interlisp-D workstation, and a small section at full size which can be moved around.
November 26, 2025 at 11:24 AM
interlisp.org
How long have you been using Lisp? Any dialect, including Emacs Lisp.

1. less than 1 year
2. 1-3 years
3. more than 3 years
4. I don't use Lisp

#interlisp #lisp #ProgLang
November 23, 2025 at 10:20 AM
interlisp.org
Interlisp source files embed control codes to style the code viewed in the Medley environment, which displays the proper fonts and text attributes. To view the formatted code on modern systems run the "lsee" shell script from a terminal.

github.com/Interlisp/me...

#interlisp #lisp #linux
Screenshot of a Linux terminal window that displays a portion of an Interlisp source file. The code is formatted with syntax highlighting and text colored in white, red, green, and yellow.
November 20, 2025 at 9:03 AM
interlisp.org
Gauges is a class library of the LOOPS Interlisp object extension (Lisp Object-Oriented Programming System). It provides meters, dials, scales, and other graphical user interface elements for monitoring and displaying data.

files.interlisp.org/medley/loops...

#interlisp #oop #lisp #retrocomputing
files.interlisp.org
November 17, 2025 at 7:32 PM
interlisp.org
We are redesigning the Interlisp bibliography for improved browsing and more informative entries. It's a work in progress and your feedback is welcome.

interlisp.org/history/bibl...

#bibliography #interlisp #lisp #retrocomputing
Bibliography
(This bibliography is kept in sync with our Zotero collection Library.
interlisp.org
November 14, 2025 at 9:26 AM
interlisp.org
Ryan Burnside entered the Autumn Lisp Game Jam 2025 with Interlisp Hungarian Rings, a puzzle he wrote in Interlisp. The project page provides instructions for downloading and playing the game:

itch.io/jam/autumn-l...

#LispGameJam #interlisp #lisp #game
Rate Interlisp Hungarian Rings by Pixel_Outlaw for Autumn Lisp Game Jam 2025
My second game using the Medley Interlisp environment
itch.io
November 11, 2025 at 11:06 AM
interlisp.org
On World Digital Preservation Day 2025 Eleanor Young gave the virtual talk "The Medley Interlisp Project: Reviving a Historical Software System". The video recording and transcript are available here:

psu.mediaspace.kaltura.com/media/The+Me...

#WDPD2025 #interlisp #lisp #retrocomputing
The Medley Interlisp Project: Reviving a Historical Software System - Penn State MediaSpace
psu.mediaspace.kaltura.com
November 8, 2025 at 10:13 AM
interlisp.org
On World Digital Preservation Day, Nov 6, 2025, Eleanor Young will give the virtual talk The Medley Interlisp Project: Reviving a Historical Software System. Details:

www.dpconline.org/events/world...

About WDPD:

www.dpconline.org/events/world...

#WDPD2025 #interlisp #lisp #retrocomputing
World Digital Preservation Day Events 2025 - Digital Preservation Coalition
www.dpconline.org
November 5, 2025 at 10:26 AM
interlisp.org
These books document different aspects of the Medley Interlisp environment: the API and using the interactive tools.

Medley Interlisp: Interactive Programming Environment
interlisp.org/documentatio...

Medley Interlisp: Interactive Programming Tools
interlisp.org/documentatio...

#interlisp #lisp
interlisp.org
November 3, 2025 at 11:05 AM