Star Trek: Alter Course

Purpose

A simulation is a system model that has to be played. This one is a single-player strategy game whose interesting constraint is that the world must behave the same way twice: the same inputs from the same state produce the same outcome.

It is built for the pleasure of building it, and it is a legitimate place to practise state modelling without a production consequence.

Operating model

The world is authoritative state, and every change to it goes through a named transition. Ship systems have explicit authority over what they can change, which keeps causality traceable when something unexpected happens twenty turns later.

Saves are versioned. A save written by an older build is migrated forward rather than rejected or silently misread.

Practices

Model is the world and ship representation — entities, state, and the rules that connect them.

Control is system authority: which subsystem may change which part of the world, and through what transition.

Recover is save migration, which is the same problem as a schema migration wearing a different costume.

Verify is determinism itself. A simulation that cannot reproduce a run cannot be debugged.

Architecture

Deterministic state transitions, an explicit world model, and versioned persistence. Randomness, where it exists, is seeded and part of the saved state rather than drawn fresh at read time.

The rejected shortcut was letting subsystems mutate world state directly for convenience. It works immediately and makes every later bug unattributable.

Evidence

The repository is public. Its LICENSE.md covers mixed rights, so it is described here as public source rather than open source, and the use terms need reading before reuse. It is a fan project: it is not sold, and no commercial availability is claimed or implied.