We revived Poplog — natively on Apple Silicon, Raspberry Pi 5, and RISC-V

We just published one of our most ambitious open-source efforts yet: a native revival of Poplog.

Poplog is a piece of AI history — the University of Sussex’s multi-language development environment, built around fast incremental compilers for four interactive languages (Pop-11, Prolog, Common Lisp, Standard ML) that share one virtual machine and one saved image and interoperate freely. It taught a generation of AI and cognitive science, then quietly fell off the modern platform map. We brought it back to the silicon people actually run in 2026 — and then took it further than the original ever went.

The work stands on W. Hebisch’s Poplog sources, with a great deal of history reconstructed by hand from the Internet Archive and scattered corners of the web. It was carried out with Claude as a pair-porting partner — down into the assembler, the frame contracts, and the instruction-cache bugs.

Three new native ports

Poplog emits real machine code, so each port is a code generator, not a recompile:

• Apple Silicon / macOS (arm64) — a native Mach-O port, self-hosting, all four languages, C↔Pop callbacks, ad-hoc signed with no entitlements.
• Raspberry Pi 5 / AArch64 Linux — validated on the Pi 5, written to the generic armv8-a baseline so it travels to other ARM64 boards.
• RISC-V / riscv64 Linux — a native RV64GC port, self-hosting on a StarFive VisionFive (dual SiFive U74), validation suite 14/14.

Four new things on top of the port

• A fifth language — Forth. A first-class Poplog subsystem where colon definitions compile to native machine code through the incremental compiler (not threaded interpretation). Testbench 21/21 on macOS arm64 and RISC-V.
• A real ELIZA. A faithful implementation of Weizenbaum’s original 1966 DOCTOR algorithm — keyword ranking, decomposition/reassembly, reflection, and memory — in Pop-11, validated against the original 1966 script.
• Experimental native graphics. An optional Dear ImGui backend — Metal + Cocoa on macOS, SDL3 + OpenGL3 on macOS or Linux (Wayland/X11/KMS, plus headless software rendering for CI) — with the classic rc_graphic turtle library ported on top so old Pop-11 graphics code runs unchanged.
• A published benchmark suite. Engine micro-benchmarks as the median of 30 runs with bootstrap confidence intervals, across five machines — Intel i7, Apple M2, Apple M5 Pro, Raspberry Pi 5, and the RISC-V VisionFive — with Python and Perl baselines.

We also wrote the porting knowledge down: a porting recipe, a guide to hosting a new language on the VM, the AArch64 frame contract, RISC-V notes, and forensic write-ups of individual codegen bugs — so the next architecture is a documented walk, not an archaeology dig.

The whole system builds and bootstraps from source via a self-contained Nix flake (nix build .#poplog). Source, ports, docs, and benchmarks on github.com/IoTone/poplog.