Forth: The programming language that writes itself

What were the most common mistakes you saw people new to Forth making? Being afraid of global variables is one of them, I infer.

FORTH was an alternative language for small systems. From the viewpoint of a BASIC programmer in 1981 the obvious difference between BASIC and all the other languages which that you could write your own functions to add "words" to the language. FORTH, like Lisp, lets you not only write functions but create new control structures based on "words" having both a compile-time and run-time meaning.

FORTH's answer to line numbers in BASIC was that it provided direct access to blocks (usually 1024 bytes) on the disk with a screen editor (just about a screenful on a 40x25) You could type your code into blocks and later load them into the interpreter. Circa 1986 I wrote a FORTH for the TRS-80 Color Computer running the OS-9 operating system and instead of using blocks it had POSIX-style I/O functions.

FORTH was faster than BASIC and better for systems work, but BASIC was dominant. Probably the best way to use FORTH was to take advantage of it's flexibility to create a DSL that you write your applications in.

1. Hardware enthusiasts who specifically love the Amiga's original hardware, its peripherals, and the early post-Commodore direction (PowerPC accelerators), and/or modding all of the above. These sort of people used WarpOS back in the day and probably use MorphOS or AmigaOS 4 today. The question is whether, for these people, modern single-board computers "count" as Amigas or not.

2. Nostalgic enthusiasts of the system that the Amiga was, who are happy with a real Amiga, or with an emulated one, or an emulated one running on some board in a box shaped like an Amiga. Possibly with a non-Amiga UI to boot some classic games. These enthusiasts may enjoy fake floppy drive sounds that remind them of booting disks in their youth.

3. Software enthusiasts of the Amiga's OS, and the directions it took that were different from its contemporaries, and the software ecosystem that came from it. These people have a longer user-startup than startup-sequence. They probably have most of Aminet downloaded. These people might be interested in other alternative OSes, e.g. QNX or BeOS. If they're still using Amiga hardware, or emulators, they'd be interested in AmigaOS 3.5/3.9 and 3.1.4/3.2. This can also include AROS and the work to get it running on native hardware, not just m68k but also x86 and arm... but it's unlikely that it will ever support as broad a range of hardware that Linux does, which limits how many people would want to use it, because it's unlikely to be able to drive a random modern laptop.

4. The reverse of 3, Amiga users that were big UNIX fans, e.g. Fred Fish, the sort of people who ran GeekGadgets and replaced their AmigaShell with pdksh. They probably just moved wholesale to Linux and didn't look back.

There are probably other categories, but I think the one you're looking for is 5: enthusiasts of the Amiga's look and feel, but not its broader OS or its software. If they did care about that, they'd be in groups 2 and 3, and emulators or alternative AmigaOSes would satisfy them most.

I can't say why there aren't many alternative desktops for Linux. Probably because it takes a lot of resources to build a full desktop environment for linux - a Window Manager, or even just an existing Window Manager theme is not enough. A file browser is not enough. Ultimately it takes the applications themselves to play along, which only works when have the clout to make people write software in your style (e.g. KDE, GNOME, Windows, macOS, Android, etc.).

The only alternative UI taken from retro machines to Linux, that I can think of, is ROX Desktop (https://en.wikipedia.org/wiki/ROX_Desktop) with its ROX-Filer... and even that doesn't look entirely like RISC OS, which you could be running instead of Linux.

That is only possible for a very limited subset of lambda terms. For example, it's not possible for the one-point basis

    A = λx λy λz. x z (y (λw. z))

https://factorcode.org

The latest release of 0.100 was September 2024, and we are getting close to a new release which we hope to do end of the year or so.

https://github.com/factor/factor

The cross-platform UI that Factor has works on macOS, Windows, and Linux. On Linux, it unfortunately still uses a GTK2-GLext project for the OpenGL widget that we render into, but modern GTK3/4 has a Gtk.GlArea that we need to switch to using which will improve the compatibility on Wayland. However, it works fine with even the latest Ubuntu 25.10 release.

And of course, you could use other libraries easily, such as Raylib:

https://re.factorcode.org/2025/05/raylib.html