third VS foth

My first programming languages were x86 assembly and Forth. My Dad was into Forth, and I learned programming from him. I wrote several x86 Forth systems for DOS as a teenager, culminating in a somewhat-polished ANS compatible one I called "Third": https://github.com/benhoyt/third -- it's kind of amazing being able to have a fully bootstrapped Forth compiler (including an assembler) in a couple thousand lines of code.

Just the other day I transcribed an old article I had co-written for the Forth Dimensions magazine. I still like the ideas in Forth, but the stack manipulation quickly gets tedious and is very hard to read. Just look at the code examples in https://benhoyt.com/writings/forth-lookup-tables/ -- especially Search-Table. Yikes! Yes, naming things is hard, but apparently not naming them is even harder.

I just finished transcribing this from the scanned PDF, and thought it might be interesting to others. It certainly took me back! I was really into Forth as a teenager, and wrote several of my own Forth compilers [1]. It's a unique and interesting language, though most Forthers spend too much time writing their own compilers and being language zealots instead of getting things done. It's hard to believe anyone could think the Search-Table code in "Figure Five" is sane. There's more stack-effect tracking than code!

[1] For example, "Third", a 16-bit self-hosting Forth compiler for DOS: https://github.com/benhoyt/third

My dad, who was a minister by day and Forth hacker by night, got me into programming when I was a teenager, and Forth and x86 assembly were my first languages. I wrote a small self-hosting Forth compiler for 8086 DOS (https://github.com/benhoyt/third), a tiny 32-bit Forth operating system for the 386 (I guess you'd call it "bare metal" today). Incidentally, my brother used my Third compiler at his work for a few years to write test scripts for embedded systems.

I still love the simplicity of Forth, and the fact that you can get a full Forth system going in a few KB on a new microcontroller. I learned the basics of assemblers, bootstrapped compilers (though not parsers, because Forth doesn't need a "real" parser), recursion, how to implement control structures, various kinds of bytecode (called "threaded code" in the Forth world), linked lists, hash tables, and so on. I also dislike 3rd party dependencies to this day (Forth has a pretty extreme not-invented here culture).

I was really intrigued by Factor when it came out (https://factorcode.org/), as a modern incarnation of Forth, but I never really used it. By that point I had a "real" programming job and was doing absurd things like writing CGI scripts in C, until I discovered Python in the early 2000's. I stuck with Python for many years and really liked it, though more recently I've moved to Go.

I learned a lot by playing with Forth as a teenager, and I'm really grateful for the language. It was an amazing way to start programming.

I hacked up a simple forth-like system in golang, by following the overview posted in this hackernews comment-chain:

https://news.ycombinator.com/item?id=13082825

The result is here:

https://github.com/skx/foth

It's not real, but it was a pretty fun experiment regardless.

Here's one of the many forks that brings it up to 64-bit:

https://github.com/matematikaadit/jombloforth

If you like forth there's an awesome series of comments here on hacker news on building a simple variant in a few simple steps:

https://news.ycombinator.com/item?id=13082825

I took that, and built a simple forth-like system, in golang following the original recipe and breaking it down into simple steps for learning-purposes:

https://github.com/skx/foth

I'll always vote up submissions referencing anything FORTH related. For me FORTH is as much fun as lisp appears to be for others. I've never really done much with it, but I always like the simplicity and the ability to reason about it.

Sure FORTH has problems of its own, but it's always nice to use. I've hacked up a couple of simple FORTH-like systems over the years, most recently this one which was inspired by a thread on this site:

https://github.com/skx/foth

A lot of people go through guides of writing a lisp, I'd love to urge people to try writing a simple FORTH interpreter instead, or even something somewhat related such as TCL.

There's even a recipe posted in a couple of comments here:

https://news.ycombinator.com/item?id=13082825

I followed that guide to implement a simple FORTH-like system in golang:

https://github.com/skx/foth

As I was following the implementation recipe I broke it down into "educational steps". Although it isn't a true FORTH it is pretty easy to understand and useful enough to embed inside other applications.

Now and again I consider doing it again, but using a real return-stack to remove the hardcoded control-flow words from the interpreter, but I never quite find the time.

I actually hacked up a simple forth-like system, after reading a brief howto here on hackernews:

https://github.com/skx/foth/

Here's the thread which has the barebones overview which inspired me:

https://news.ycombinator.com/item?id=13082825

I could have taken it further, but the implementation there is not "real" in the sense that there is no real return-stack, so you can't implement IF-statements using the lower-level primitives.

That said it is a good starting point, and I had some fun doing it. I'd guesstimate it is more of a single weekend project though, rather than longer.