1: Design a bytecode. 2: Write a compiler. 3: Write an interpreter.
It seems like it would be simpler to not bother with 1 and 3 and instead use machine code as the bytecode. A side benefit is that programs will run faster.
I think it is easy to generate machine code for x86_64, ARM64 and risvc64, as long as you don't mind it being 3x larger and slower than an optimizing compiler would generate. It ought to be easy because it is possible to only target the common subset of features these architectures support.
I made a start, https://github.com/abainbridge/mortar, but haven't got much past being able to compile and run a Fibonacci sequence generator. I have no experience with language design or compiler implementation. I was somewhat gobsmacked when the fib generator ran 380x faster than an almost identical looking Python program.
Any comments or suggestions, including, "that's a bad idea, you will fail because of XYZ", or, "save yourself the effort, here's one I wrote earlier..."?
The description of uxn and varvara are also small and might need only two pages (I did not write it).
I also remember reading in a book that someone made a game on Atari in 2 kilobytes, and described how they could make it fit (by making the map symmetric, etc), which was rejected because they had 4 kilobyte cartridges by then. (The article in this submission also links to a different game that (probably) someone else made in 2 kilobytes, but this time with JavaScript and HTML. Atari and uxn/varvara are much simpler systems than HTML/JavaScript, though.)
Of course, Hal was a genius.
The very first J interpreter prototype fit on a single printed page and consisted of only about 1,000 to 1,200 bytes of C source code. This legendary piece of code, later famously dubbed the "Incunabulum" (meaning cradle or early stage) of the J programming language, spanned exactly 122 lines of extremely dense text. Iverson soon showed this one-page prototype to Roger Hui. Hui later recalled that his first reaction to the code was utter confusion—it looked like nothing he had ever seen before ("Is this even C?").
Take this lisp ;-)
just my 2 ct
The other part for me is working within tight constraints. A couple of years back I made an Operating System that fits a bootloader (I was low-key hoping to find in the list :P) Not really golfing but surely a good exercise in playing within constraints.
If anybody wants to take a look https://github.com/shikaan/osle
Constructing Language Processors for Little Languages by Randy Kaplan - https://www.amazon.com/dp/0471597538?lv=shuf&channelId=500&p...
Also, JimTCL.
Thanks for sharing.