<![CDATA[Printing rich text to windows is one of the planned features of DandeGUI, the GUI library for Medley Interlisp I'm developing in Common Lisp. I finally got around to this and implemented the GUI:WITH-TEXT-STYLE macro which controls the attributes of text printed to a window, such as the font family and face. GUI:WITH-TEXT-STYLE establishes a context in which text printed to the stream associated with a TEdit window is rendered in the style specified by the arguments. The call to GUI:WITH-TEXT-STYLE here extends the square root table example by printing the heading in a 12-point bold sans serif font: (gui:with-output-to-window (stream :title "Table of square roots") (gui:with-text-style (stream :family :sans :size 12 :face :bold) (format stream "~&Number~40TSquare Root~2%")) (loop for n from 1 to 30 do (format stream "~&~4D~40T~8,4F~%" n (sqrt n)))) The code produces this window in which the styled column headings stand out: Medley Interlisp window of a square root table generated by the DandeGUI GUI library. The :FAMILY, :SIZE, and :FACE arguments determine the corresponding text attributes. :FAMILY may be a generic family such as :SERIF for an unspecified serif font; :SANS for a sans serif font; :FIX for a fixed width font; or a keyword denoting a specific family like :TIMESROMAN. At the heart of GUI:WITH-TEXT-STYLE is a pair of calls to the Interlisp function PRINTOUT that wrap the macro body, the first for setting the font of the stream to the specified style and the other for restoring the default: (DEFMACRO WITH-TEXT-STYLE ((STREAM &KEY FAMILY SIZE FACE) &BODY BODY) (ONCE-ONLY (STREAM) `(UNWIND-PROTECT (PROGN (IL:PRINTOUT ,STREAM IL:.FONT (TEXT-STYLE-TO-FD ,FAMILY ,SIZE ,FACE)) ,@BODY) (IL:PRINTOUT ,STREAM IL:.FONT DEFAULT-FONT)))) PRINTOUT is an Interlisp function for formatted output similar to Common Lisp's FORMAT but with additional font control via the .FONT directive. The symbols of PRINTOUT, i.e. its directives and arguments, are in the Interlisp package. In turn GUI:WITH-TEXT-STYLE calls GUI::TEXT-STYLE-TO-FD, an internal DandeGUI function which passes to .FONT a font descriptor matching the required text attributes. GUI::TEXT-STYLE-TO-FD calls IL:FONTCOPY to build a descriptor that merges the specified attributes with any unspecified ones copied from the default font. The font descriptor is an Interlisp data structure that represents a font on the Medley environment. #DandeGUI #CommonLisp #Interlisp #Lisp a href="https://remark.as/p/journal.paoloamoroso.com/changing-text-style-for-dandegui-window-output"Discuss.../a Email | Reply @amoroso@oldbytes.space !--emailsub--]]>

<![CDATA[I continued working on DandeGUI, a GUI library for Medley Interlisp I'm writing in Common Lisp. I added two new short public functions, GUI:CLEAR-WINDOW and GUI:PRINT-MESSAGE, and fixed a bug in some internal code. GUI:CLEAR-WINDOW deletes the text of the window associated with the Interlisp TEXTSTREAM passed as the argument: (DEFUN CLEAR-WINDOW (STREAM) "Delete all the text of the window associated with STREAM. Returns STREAM" (WITH-WRITE-ENABLED (STR STREAM) (IL:TEDIT.DELETE STR 1 (IL:TEDIT.NCHARS STR))) STREAM) It's little more than a call to the TEdit API function IL:TEDIT.DELETE for deleting text in the editor buffer, wrapped in the internal macro GUI::WITH-WRITE-ENABLED that establishes a context for write access to a window. I also wrote GUI:PRINT-MESSAGE. This function prints a message to the prompt area of the window associated with the TEXTSTREAM passed as an argument, optionally clearing the area prior to printing. The prompt area is a one-line Interlisp prompt window attached above the title bar of the TEdit window where the editor displays errors and status messages. (DEFUN PRINT-MESSAGE (STREAM MESSAGE &OPTIONAL DONT-CLEAR-P) "Print MESSAGE to the prompt area of the window associated with STREAM. If DONT-CLEAR-P is non NIL the area will be cleared first. Returns STREAM." (IL:TEDIT.PROMPTPRINT STREAM MESSAGE (NOT DONT-CLEAR-P)) STREAM) GUI:PRINT-MESSAGE just passes the appropriate arguments to the TEdit API function IL:TEDIT.PROMPTPRINT which does the actual printing. The documentation of both functions is in the API reference on the project repo. Testing DandeGUI revealed that sometimes text wasn't appended to the end but inserted at the beginning of windows. To address the issue I changed GUI::WITH-WRITE-ENABLED to ensure the file pointer of the stream is set to the end of the file (i.e -1) prior to passing control to output functions. The fix was to add a call to the Interlisp function IL:SETFILEPTR: (IL:SETFILEPTR ,STREAM -1) #DandeGUI #CommonLisp #Interlisp #Lisp a href="https://remark.as/p/journal.paoloamoroso.com/adding-window-clearing-and-message-printing-to-dandegui"Discuss.../a Email | Reply @amoroso@oldbytes.space !--emailsub--]]>

<![CDATA[I'm working on DandeGUI, a Common Lisp GUI library for simple text and graphics output on Medley Interlisp. The name, pronounced "dandy guy", is a nod to the Dandelion workstation, one of the Xerox D-machines Interlisp-D ran on in the 1980s. DandeGUI allows the creation and management of windows for stream-based text and graphics output. It captures typical GUI patterns of the Medley environment such as printing text to a window instead of the standard output. The main window of this screenshot was created by the code shown above it. A text output window created with DandeGUI on Medley Interlisp and the Lisp code that generated it. The library is written in Common Lisp and exposes its functionality as an API callable from Common Lisp and Interlisp code. Motivations In most of my prior Lisp projects I wrote programs that print text to windows. In general these windows are actually not bare Medley windows but running instances of the TEdit rich-text editor. Driving a full editor instead of directly creating windows may be overkill, but I get for free content scrolling as well as window resizing and repainting which TEdit handles automatically. Moreover, TEdit windows have an associated TEXTSTREAM, an Interlisp data structure for text stream I/O. A TEXTSTREAM can be passed to any Common Lisp or Interlisp output function that takes a stream as an argument such as PRINC, FORMAT, and PRIN1. For example, if S is the TEXTSTREAM associated with a TEdit window, (FORMAT S "~&Hello, Medley!~%") inserts the text "Hello, Medley!" in the window at the position of the cursor. Simple and versatile. As I wrote more GUI code, recurring patterns and boilerplate emerged. These programs usually create a new TEdit window; set up the title and other options; fetch the associated text stream; and return it for further use. The rest of the program prints application specific text to the stream and hence to the window. These patterns were ripe for abstracting and packaging in a library that other programs can call. This work is also good experience with API design. Usage An example best illustrates what DandeGUI can do and how to use it. Suppose you want to display in a window some text such as a table of square roots. This code creates the table in the screenshot above: (gui:with-output-to-window (stream :title "Table of square roots") (format stream "~&Number~40TSquare Root~2%") (loop for n from 1 to 30 do (format stream "~&~4D~40T~8,4F~%" n (sqrt n)))) DandeGUI exports all the public symbols from the DANDEGUI package with nickname GUI. The macro GUI:WITH-OUTPUT-TO-WINDOW creates a new TEdit window with title specified by :TITLE, and establishes a context in which the variable STREAM is bound to the stream associated with the window. The rest of the code prints the table by repeatedly calling the Common Lisp function FORMAT with the stream. GUI:WITH-OUTPUT-TO-WINDOW is best suited for one-off output as the stream is no longer accessible outside of its scope. To retain the stream and send output in a series of steps, or from different parts of the program, you need a combination of GUI:OPEN-WINDOW-STREAM and GUI:WITH-WINDOW-STREAM. The former opens and returns a new window stream which may later be used by FORMAT and other stream output functions. These functions must be wrapped in calls to the macro GUI:WITH-WINDOW-STREAM to establish a context in which a variable is bound to the appropriate stream. The DandeGUI documentation on the project repository provides more details, sample code, and the API reference. Design DandeGUI is a thin wrapper around the Interlisp system facilities that provide the underlying functionality. The main reason for a thin wrapper is to have a simple API that covers the most common user interface patterns. Despite the simplicity, the library takes care of a lot of the complexity of managing Medley GUIs such as content scrolling and window repainting and resizing. A thin wrapper doesn't hide much the data structures ubiquitous in Medley GUIs such as menus and font descriptors. This is a plus as the programmer leverages prior knowledge of these facilities. So far I have no clear idea how DandeGUI may evolve. One more reason not to deepen the wrapper too much without a clear direction. The user needs not know whether DandeGUI packs TEdit or ordinary windows under the hood. Therefore, another design goal is to hide this implementation detail. DandeGUI, for example, disables the main command menu of TEdit and sets the editor buffer to read-only so that typing in the window doesn't change the text accidentally. Using Medley Common Lisp DandeGUI relies on basic Common Lisp features. Although the Medley Common Lisp implementation is not ANSI compliant it provides all I need, with one exception. The function DANDEGUI:WINDOW-TITLE returns the title of a window and allows to set it with a SETF function. However, the SEdit structure editor and the File Manager of Medley don't support or track function names that are lists such as (SETF WINDOW-TITLE). A good workaround is to define SETF functions with DEFSETF which Medley does support along with the CLtL macro DEFINE-SETF-METHOD. Next steps At present DandeGUI doesn't do much more than what described here. To enhance this foundation I'll likely allow to clear existing text and give control over where to insert text in windows, such as at the beginning or end. DandeGUI will also have rich text facilities like printing in bold or changing fonts. The windows of some of my programs have an attached menu of commands and a status area for displaying errors and other messages. I will eventually implement such menu-ed windows. To support programs that do graphics output I plan to leverage the functionality of Sketch for graphics in a way similar to how I build upon TEdit for text. Sketch is the line drawing editor of Medley. The Interlisp graphics primitives require as an argument a DISPLAYSTREAM, a data stracture that represents an output sink for graphics. It is possible to use the Sketch drawing area as an output destination by associating a DISPLAYSTREAM with the editor's window. Like TEdit, Sketch takes care of repainting content as well as window scrolling and resizing. In other words, DISPLAYSTREAM is to Sketch what TEXTSTREAM is to TEdit. DandeGUI will create and manage Sketch windows with associated streams suitable for use as the DISPLAYSTREAM the graphics primitives require. #DandeGUI #CommonLisp #Interlisp #Lisp a href="https://remark.as/p/journal.paoloamoroso.com/dandegui-a-gui-library-for-medley-interlisp"Discuss.../a Email | Reply @amoroso@fosstodon.org !--emailsub--]]>

<![CDATA[I spoke too soon when I said I was enjoying the stability of Linux. I have been using Linux Mint Cinnamon on a System76 Merkaat PC with no major issues since July of 2024. But a few days ago a routine system update of Mint 22 dumped me to the text console. A fresh install of Mint 22.1, the latest release, brought the system back online. I had backups and the mishap luckily turned out as just an annoyance that consumed several hours of unplanned maintenance. It all started when the Mint Update Manager listed several packages for update, including the System76 driver and tools. Oddly, the Update Manager also marked for removal several packages including core ones such as Xorg, Celluloid, and more. The smooth running of Mint made my paranoid side fall asleep and I applied the recommend changes. At the next reboot the graphics session didn't start and landed me at the text console with no clue what happened. I don't use Timeshift for system snapshots as I prefer a fresh install and restore of data backups if the system breaks. Therefore, to fix such an issue apparently related to Mint 22 the obvious route was to install Mint 22.1. Besides, this was the right occasion to try the new release. On my Raspberry Pi 400 I ran dd to flash a bootable USB stick with Mint 22.1. I had no alternatives as GNOME Disks didn't work. The Merkaat failed to boot off the stick, possibly because I messed with the arguments of dd. I still had around a USB stick with Mint 22 and I used it to freshly install it on the Merkaat. Then I immediately ran the upgrade to Mint 22.1 which completed successfully unlike a prior upgrade attempt. Next, I tried to install the System76 driver with sudo apt install system76-driver but got a package not found error. At that point I had already added the System76 package repository to the APT sources and refreshing the Mint Update Manager yielded this error: Could not refresh the list of updates Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages Aside from the errors the system was up and running on the Merkaat, so with Nemo I reflashed the Mint 22.1 stick. This time the PC did boot off the stick and let me successfully install Mint 22.1. Restoring the data completed the system recovery. I left out the System76 driver as it's the primary suspect, possibly due to package conflicts. Mint detects and supports all hardware of the Merkaat anyway and it's only prudent to skip the package for the time being. Besides improvements under the hood, Mint 22.1 features a redesigned default Cinnamon theme. No major changes, I feel at home. The main takeaway of this adventure is that it's better to have a bootable USB stick ready with the latest Mint release, even if I don't plan to upgrade immediately. Another takeaway is the Pi 400 makes for a viable backup computer that can support my major tasks, should it take longer to recover the Merkaat. However, using the device for making bootable media is problematic as little flashing software is available and some is unreliable. Finally, over decades of Linux experience I honed my emergency installation skills so much I can now confidently address most broken system situations. #linux #pi400 a href="https://remark.as/p/journal.paoloamoroso.com/an-unplanned-upgrade-to-linux-mint-22-1-cinnamon"Discuss.../a Email | Reply @amoroso@fosstodon.org !--emailsub--]]>

<![CDATA[My journey to Lisp began in the early 1990s. Over three decades later, a few days ago I rediscovered the first Lisp environment I ever used back then which contributed to my love for the language. Here it is, PC Scheme running under DOSBox-X on my Linux PC: Screenshot of the PC Scheme Lisp development environment for MS-DOS by Texas Instruments running under DOSBox-X on Linux Mint Cinnamon. Using PC Scheme again brought back lots of great memories and made me reflect on what the environment taught me about Lisp and Lisp tooling. As a Computer Science student at the University of Milan, Italy, around 1990 I took an introductory computers and programming class taught by Prof. Stefano Cerri. The textbook was the first edition of Structure and Interpretation of Computer Programs (SICP) and Texas Instruments PC Scheme for MS-DOS the recommended PC implementation. I installed PC Scheme under DR-DOS on a 20 MHz 386 Olidata laptop with 2 MB RAM and a 40 MB hard disk drive. Prior to the class I had read about Lisp here and there but never played with the language. SICP and its use of Scheme as an elegant executable formalism instantly fascinated me. It was Lisp love at first sight. The class covered the first three chapters of the book but I later read the rest on my own. I did lots of exercises using PC Scheme to write and run them. Soon I became one with PC Scheme. The environment enabled a tight development loop thanks to its Emacs-like EDWIN editor that was well integrated with the system. The Lisp awareness of EDWIN blew my mind as it was the first such tool I encountered. The editor auto-indented and reformatted code, matched parentheses, and supported evaluating expressions and code blocks. Typing a closing parenthesis made EDWIN blink the corresponding opening one and briefly show a snippet of the beginning of the matched expression. Paying attention to the matching and the snippets made me familiar with the shape and structure of Lisp code, giving a visual feel of whether code looks syntactically right or off. Within hours of starting to use EDWIN the parentheses ceased to be a concern and disappeared from my conscious attention. Handling parentheses came natural. I actually ended up loving parentheses and the aesthetics of classic Lisp. Parenthesis matching suggested me a technique for writing syntactically correct Lisp code with pen and paper. When writing a closing parenthesis with the right hand I rested the left hand on the paper with the index finger pointed at the corresponding opening parenthesis, moving the hands in sync to match the current code. This way it was fast and easy to write moderately complex code. PC Scheme spoiled me and set the baseline of what to expect in a Lisp environment. After the class I moved to PCS/Geneva, a more advanced PC Scheme fork developed at the University of Geneva. Over the following decades I encountered and learned Common Lisp, Emacs, Lisp, and Interlisp. These experiences cemented my passion for Lisp. In the mid-1990s Texas Instruments released the executable and sources of PC Scheme. I didn't know it at the time, or if I noticed I long forgot. Until a few days ago, when nostalgia came knocking and I rediscovered the PC Scheme release. I installed PC Scheme under the DOSBox-X MS-DOS emulator on my Linux Mint Cinnamon PC. It runs well and I enjoy going through the system to rediscover what it can do. Playing with PC Scheme after decades of Lisp experience and hindsight on computing evolution shines new light on the environment. I didn't fully realize at the time but the product packed an amazing value for the price. It cost $99 in the US and I paid it about 150,000 Lira in Italy. Costing as much as two or three texbooks, the software was affordable even to students and hobbyists. PC Scheme is a rich, fast, and surprisingly capable environment with features such as a Lisp-aware editor, a good compiler, a structure editor and other tools, many Scheme extensions such as engines and OOP, text windows, graphics, and a lot more. The product came with an extensive manual, a thick book in a massive 3-ring binder I read cover to cover more than once. A paper on the implementation of PC Scheme sheds light on how good the system is given the platform constraints. Using PC Scheme now lets me put into focus what it taught me about Lisp and Lisp systems: the convenience and productivity of Lisp-aware editors; interactive development and exploratory programming; and a rich Lisp environment with a vast toolbox of libraries and facilities — this is your grandfather's batteries included language. Three decades after PC Scheme a similar combination of features, facilities, and classic aesthetics drew me to Medley Interlisp, my current daily driver for Lisp development. #Lisp #MSDOS #retrocomputing a href="https://remark.as/p/journal.paoloamoroso.com/rediscovering-the-origins-of-my-lisp-journey"Discuss.../a Email | Reply @amoroso@fosstodon.org !--emailsub--]]>