Very cool and I like the idea of a "meta-assembler." The most-recent version of flatassembler (fasm 2) is built with fasmg which is also a "meta-assembler" of sorts, in that it also doesn't directly support a specific instruction set and instead is a very powerful macro assembler. I'm keen to check out functionality overlaps between the two implementations.

https://board.flatassembler.net/topic.php?t=19389

https://flatassembler.net/download.php

At first I thought it was useless: "but each ISA will still end up having different effective syntax because the underlying macro systems will not be designed the same".

But then I reread it and realised I was not paying attention to the usecase. It's about making it easy to write assemblers. So this isn't for your Arms and RISC-Vs it's for your random niche microcontrollers where the vendor-provided toolchain kinda sucks.

Seems cool!

I've experienced a couple of under-documented assemblers in my time. In neither case did this turn out to be that much of a problem in practice, but I guess I just don't write that much assembly.

Super fun site!

Did you get inspiration from other assemblers or macro processors?

You have it running on a TRS-80, how does that work? I had no idea Rust could target a TRS-80.

I am getting hints of Forth, Lisp and TCL.

How would you go about laying out structs in memory?

I am sure you considered an internal DSL, what caused you go with something stand alone?

Any thoughts on adding a constraint solver, like Z3 and allowing end users to set constraints on things like the size of a jump.

I could see taking this an growing it into a compiler by making macro(macro(macros txt)))

Is there an internal IR?

Projects for inspiration

https://github.com/mattbierner/Template-Assembly

Specifying representations of machine instructions https://dl.acm.org/doi/pdf/10.1145/256167.256225

https://www.semanticscholar.org/paper/Specifying-representat...

Typed Assembly Language (TAL) https://www.cs.cornell.edu/talc/

And you haven't come across it, you are in for a treat https://en.wikipedia.org/wiki/META_II has spawned a whole trove of clones

https://en.wikipedia.org/wiki/OMeta

https://github.com/DalekBaldwin/clometa

I'm reminded of a 2016 [talk][1] where Rob Pike describes the common-denominator assembly language that the Go compiler generates. Then that assembly is translated into machine-specific code via table lookups. See the 11 minute mark.

[1]: https://www.youtube.com/watch?v=KINIAgRpkDA

Reminds me of TDASM from the turn of the century: https://web.archive.org/web/20230906054935/http://www.pengui...

I remember there were a few other meta-assemblers I came across in the 80s-90s, so this is definitely not "unchartered territory", but it's good to see another one show up.

Of course, in the other direction there are meta-disassemblers used for analysis in tools like Ghidra.