Interlisp source files embed binary control codes for text formatting such as ^F^B for bold. GitHub renders the codes as boxes in browsers other than Firefox, which strips the codes. Here's a sample file:

https://github.com/pamoroso/braincons/blob/main/BRAINCONS

Codeberg thinks the sources are binary files and doesn't render them. The same file on Codeberg:

https://codeberg.org/amoroso/braincons/src/branch/main/BRAINCONS

I'd love to migrate my Interlisp code to @Codeberg but this is a showstopper.

#interlisp #codeberg #GitHub

On May 28, 2025 Eleanor Young will give the talk "The Medley Interlisp Project: Reviving a Historical Software System" at the 2025 IEEE Canadian Conference on Electrical and Computer Engineering and Industry Summit (CCECE). She will discuss what other historical software recovery groups can learn from the Medley Interlisp Project.

https://ccece2025.ieee.ca/technical-program

https://ccece2025.ieee.ca

#retrocomputing #interlisp #lisp #SoftwarePreservation

We maintain a collection of references and quotes of what people are saying about Medley Interlisp. News stories, blog posts, online discussions, and social posts offering nice words and impressions of the system. Thanks to all!

https://interlisp.org/project/comments

#interlisp #lisp

You can use the Interlisp function SHOWGRAPH to display a graph of an S-exp laid out by LAYOUTSEXPR, as in this example of the syntax tree of a setence. More details in the documentation of the grapher library module of Medley:

http://www.bitsavers.org/pdf/xerox/interlisp-d/198809_Medley_1.0/300006_Lisp_Library_Modules_Sep88.pdf#page=147

#interlisp #lisp

A 1990 MSc dissertation on the theory and design of dialog boxes in GUIs. An overview of the field at the time, with examples also drawn from Interlisp-D such as the Trillium UI designer for Xerox copiers.

https://repository.rit.edu/cgi/viewcontent.cgi?article=1105&context=theses

#gui #retrocomputing #interlisp

Published in 1987, "Xerox LOOPS, A Friendly Primer" is a concise tutorial to the LOOPS (Lisp Object-Oriented Programming System) object extension of Interlisp. Some chapters of this copy are in the wrong order but all the content is there.

http://www.bitsavers.org/pdf/xerox/interlisp-d/198510_Koto/3102242_Xerox_LOOPS_A_Friendly_Primer_Mar87.pdf

#interlisp #lisp #oop

Are you doing something interesting with Medley Interlisp such as coding, running programs, or learning the system? We'd love to hear what you're doing.

#interlisp #lisp

To display a simple yes/no dialog call the Interlisp function MENU to create a menu with the question as the title and two centered items for the answers, as in the example. MENU returns the selected item, i.e. symbol Yes here.

#interlisp #lisp

DandeGUI now supports rich text for window output. DandeGUI is the GUI library for Medley Interlisp I'm writing in Common Lisp.

https://journal.paoloamoroso.com/changing-text-style-for-dandegui-window-output

#CommonLisp #interlisp #lisp

Developed in the late 1980s in Interlisp-D and its OOP extension LOOPS, the CHIPS system for creating graphical user interfaces consisted of a rich class library and interactive tools. This report describes CHIPS in depth:

https://eric.ed.gov/?id=ED290438

#interlisp #gui #lisp #retrocomputing

LispUsers is a collection of user contributed software that has been shipping with Interlisp and later Medley since the 1970s. To load a LispUsers program evaluate (IL:FILESLOAD file) where `file` is the program name without extension. Most come with .pdf or .TEDIT documentation that explains how to run the program.

https://files.interlisp.org/medley/lispusers

#interlisp #lisp

Now I have another #Interlisp question:

I have:

(DEFINEQ (PLOT-FN (FN SX SY C W)
(MOVETO 0 (CADR C))
(DRAWTO 200 (CADR C))
(MOVETO (CAR C) 0)
(DRAWTO (CAR C) 200)
(LET* ((L1 (MAPCAR (IOTA 50)
(FUNCTION
(LAMBDA (N)
(TIMES 200 (QUOTIENT (SUB1 N) 50)))))

;; to be continued (1/n)

@interlisp @amoroso
@kentpitman

Why do the ATAN and ARCTAN functions in #Medley #Interlisp return the result angle in degrees rather than radian?

I know the answer is (the fixnum 42), but why?

Questions over questions?

To print the contents of a window on Medley Interlisp select the Hardcopy > To a file item of the right-click menu of the title bar (first screenshot), then type a file name (second screenshot). This saves a PostScript file suitable for viewing or printing.

#interlisp #lisp

In 1976 Robert S. Boyer at SRI and J Strother Moore at Xerox PARC invented the Boyer-Moore fast string-search algorithm. Moore wrote in Interlisp the first implementation which was "10 to 50 times faster than the existing routines for searching for strings in a file", as Warren Teitelman noted in the 1976 annual report on Interlisp:

https://apps.dtic.mil/sti/tr/pdf/ADA033633.pdf#page=8

#interlisp #algorithms #retrocomputing

RPT and RPTQ (RePeaT) are Interlisp iteration expressions that evaluate a form a specified number of times, without or with quoting. This is an example, more details in the Interlisp Reference Manual:

https://interlisp.org/documentation/IRM.pdf#page=134

#interlisp #lisp

I wrote two new functions of DandeGUI, my GUI library for text and graphics output on Medley Interlisp. The first function clears the text of windows, the other prints status messages.

https://journal.paoloamoroso.com/adding-window-clearing-and-message-printing-to-dandegui

#interlisp #lisp #gui

The manual Medley for the Sun Workstation User’s Guide came with Medley Interlisp in the early 1990s. Although it's Sun specific and part of it is only of historical value, it still provides practical information such as on the Medley file system on Unix.

https://interlisp.org/documentation/SunUserGuide.pdf

#interlisp #lisp

"Which convoy escorts have inoperative sonar systems"

"What is the nearest ship to Naples with a doctor on board"

"Which cruisers have less than 50 per cent fuel on board"

"How many ships carrying oil are within 340 miles of Mayport?"

These are not ChatGPT prompts but valid queries for LADDER, a natural language interface in Interlisp developed half a century ago for accessing US Navy ship databases. More details:

https://dl.acm.org/doi/pdf/10.1145/320251.320253

#interlisp #lisp #retrocomputing

I'm abstracting the recurring user interface patterns and boilerplate of my Medley Interlisp programs and packaging them into DandeGUI, a GUI library for simple text and graphics output.

https://journal.paoloamoroso.com/dandegui-a-gui-library-for-medley-interlisp

#interlisp #lisp #gui