Cowgol is an experimental, Ada-inspired language for very small systems (6502, Z80, etc). It’s different because it’s intended to be self-hosted on these devices: the end goal is to be able to rebuild the entire compiler on an 8-bit micro.
Right now it’s in a state where you can build the cross-compiler on a PC, then use it to compile the compiler for a 6502 device, and then use that to (slowly) compile and run real programs on a 6502. It’s theoretically capable of compiling itself but need memory tuning first. (And, realistically, bugfixing.)
It’s currently targeted at a BBC Micro with Tube second processor, because that gives me a real operating system with file streams and 61kB of usable RAM, but there’s extremely basic (cross compilation only) support for the Commodore 64. (For ultra hackers only. Email me.)
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Check out the GitHub repository and build from source. (Alternatively, you can download a source snapshot from the latest release, but I suggect the GitHub repositories better because I don’t really intend to make formal releases often.) Build instructions as in the README.
We have documentation! Admittedly, not much of it.
Everything you want to know about Cowgol, the language; tl;dr: very strongly typed; Ada-like syntax; multiple return parameters; no recursion; nested functions.
An overview of Cowgol, the toolchain; tl;dr: eight-stage compiler pipeline; separate front-end and back-end; maximum RAM use: about 60kB; call graph analysis for efficient variable packing; suitable for other languages; written in pure Cowgol.
About the BBC Micro bootable floppy; tl;dr: crude, slow, not suitable for production use; requires a BBC Micro with 6502 Tube second processor although I recommend a BBC Master (mainly for the built-in editor); requires extreme patience as it takes eight minutes to compile a small program.
Cowgol is open source software available under the 2-clause BSD license. Simplified summary: do what you like with it, just don’t claim you wrote it.