Compiling Prolog to Forth [pdf]

Very interesting stuff. Apparently this is the implementation: https://github.com/dicpeynado/prolog-in-forth

Thinking about the amount of thought and energy that went into this, back in 1987 -- mostly preinternet, pre-AI. Damn.

I feel really lucky that we get to build on things like this.

Forth is so interesting.

I've been doing a lot of Forth lately; it's a kind of weird language, and it makes your brain think in a way that is very different than basically any other language out there. It allows you to work at effectively any of level of code, and allows you to easily "lift" low level code into high level.

I've been on/off developing a Forth for the NES. It mostly works, but it's still pretty buggy and I'm still learning how the PPU works so graphics will often get corrupted for things that are non-trivial, but even despite that, I was flabbergasted at how easy it was to get a Forth built for it, and even the decent performance I've been able to get when I compile it.

I don't know that I have much desire to write Forth on modern hardware, but I am still glad I learned it just so I can work at a lower level in a high-ish level language, and I do think that "learning to think in Forth" is a skill that is something most developers should do.

I assisted a graduate student a long time ago in his implementation of the Warren Machine for compiling Prolog. At its core it was essentially a threaded interpreter.