Pop-11 and the Robot Army — a free book on Poplog as an agent's command post

We wrote a book: Pop-11 and the Robot Army — Poplog as the engine behind AI agents and the machines they command. Thirty-one pages, free, and dedicated to the public domain.

It exists because reviving Poplog produced a working system that almost nobody alive knows how to drive. The forty-year paper trail is excellent and mostly assumes you are already in a 1985 Sussex lecture theatre. This is the missing on-ramp.

The premise

You have a fleet. Scouts, sappers, medics, haulers — a few today, a few hundred later — each one reporting telemetry, each one waiting for orders. Above them sits an AI agent that reads the reports, decides, and issues the orders. That agent needs a tool that can hold the whole picture in one place, change its own behaviour while running, and never make the fleet wait on a build.

The book argues that three properties Poplog has had since the 1980s are exactly what an agent-driven command post wants:

• The compiler is a procedure in the running system. Defining a new behaviour — a new order, a new triage rule — costs about fifteen microseconds and produces native machine code. An agent can extend its own tooling mid-mission.
• The whole session is a value. The heap — the fleet registry, every compiled procedure, every rule learned so far — writes to a file in milliseconds and restores in a new process. A command post that survives a restart is a file copy.
• Five languages share it. Prolog holds the chain of command, Forth runs on the robot, ML types the sensor model, Lisp plans — and one ?- at the Pop-11 prompt reaches any of them.

Everything in it was run

This is the part we care most about. Every listing was executed against the source tree while the text was written, on Apple Silicon; the outputs printed in the book are the outputs that came back. The full programs live in examples/robotarmy/ and each runs from the repository root:

File	What it shows
fleet.p	A Robot Objectclass, a word-keyed registry, muster() on the open stack, and obey() — an order interpreter built on Pop-11’s list matcher
telemetry.p	One pass over a fleet log: level counts, units ranked by fault, slowest operation — using Poplog’s @-escaped regexps and default-valued properties
c2.p	The command post as an HTTP service in pure Pop-11: GET /fleet, GET /status?unit=r1, POST /order
chain.pl	The chain of command as Prolog relations — can_order/2, reports_to/2, obeys/2
patrol.fth	Robot control words in Poplog Forth, with an early leave
signed_orders.p	HMAC-signed orders through OpenSSL via a C shim — genuine, tampered, and replayed

What’s covered

Eight chapters and a cheat sheet: the two-level virtual machine and why a language hosted on it inherits every port for free; a quickstart; Pop-11 fundamentals including the list matcher and the quoting trap; running the fleet; the five front-ends and how to cross between them; hosting a language of your own on the VM in three tiers of effort; and the C interface — exload, exacc, and the shim discipline that makes a foreign call something a robot can trust.

There are honest numbers, too. The benchmark chapter puts Poplog against CPython on identical hardware and prints the row where Python wins — runtime compilation, because compile() produces bytecode while Poplog produces machine code.

Public domain

Text, listings, diagrams and the hand-drawn cover art are released under the Creative Commons CC0 1.0 Universal public domain dedication. Copy it, translate it, teach from it. The LaTeX source is in docs/book/ with SOURCE_DATE_EPOCH pinned, so a rebuild is byte-identical to the published PDF.

Read the book · Poplog source