Guidebook Rust 02 Project

A complete, shippable Rust mod — full event + hook coverage — mirroring examples/Rust/greg_example/. Drop-in, no companion needed.

The project: examples/Rust/greg_example/

Cargo.toml (cdylib greg_rust_example) + src/greg.rs (bindings copy) + src/lib.rs:

extern "C" fn on_coins_changed(_event_id: u32, data: u64) {
    greg::log_info(&format!("[rust_example] coins changed: {data}"));
}

extern "C" fn on_any_hook(hook: *const c_char, trigger: *const c_char, json: *const c_char) {
    let (h, t, j) = greg::decode_hook(hook, trigger, json);
    greg::log_info(&format!("[rust_example] hook {h} via {t}: {j}"));
}

// in greg_mod_init, after greg::init(api):
greg::subscribe_event(greg::events::PLAYER_COIN_UPDATED, on_coins_changed);
greg::subscribe_event(greg::events::GAME_SAVED, on_game_saved);
greg::subscribe_event(greg::events::SERVER_STATUS_CHANGED, on_server_status);
greg::subscribe_event(greg::events::RACK_POSITION_QUERIED, on_rack_position);
greg::subscribe_event(greg::events::RACK_POSITION_USED, on_rack_used);
greg::subscribe_event(greg::events::CABLE_CREATED, on_cable_created);
greg::on_hook("greg.PLAYER.CoinChanged", on_any_hook);

The full example additionally covers XP, rack-freed, scene load, and shutdown logging — read it as the reference for every subscription shape (typed events take (u32, u64); hooks take (hook, trigger, json)).

Verify: build → UserLibs/Rust/rust_example.dll → restart → Rust Plugin loaded: rust_example → change money (coin lines), save the game (save line), place hardware (rack/cable lines). No companion mod required.

Reading game state (not just events)

let money = greg::get_player_money();
let (servers, broken) = (greg::get_server_count(), greg::get_broken_server_count());
let (x, y, z, _ry) = greg::get_player_position();
if greg::get_free_technician_count() > 0 {
    greg::dispatch_repair_server();
}
greg::notify("Rust says hi.");

Writes (set_player_money, set_time_scale, trigger_save, …) work the same way — still local-only: Rust never touches networking or saves directly.

Config flags

let verbose = greg::config_get_bool("rust_example", "verbose", false);
greg::config_set_bool("rust_example", "verbose", true);

Only bool exists on table v1; int/float/string helpers exist in greg.rs but are inert until the bridge binds them — check before relying on them.

Troubleshooting

Symptom	Cause	Fix
does not export core functions	Missing greg_mod_info/greg_mod_init (name mangling)	#[no_mangle] pub extern "C", crate-type = ["cdylib"]
Crash on first subscribe/hook	Hand-rolled table with wrong field order	Use greg.rs unmodified — layout asserts guard it
api_version mismatch confusion	Example reports table version, not framework version	Report greg::TABLE_VERSION; pin framework VERSION in your README
No events arriving	Wrong event ID	Use greg::events::* (mirrors EventIds), never magic numbers
Game stutters	Work in greg_mod_update	Move to event callbacks; update stays near-empty

Checkpoint: DLL loads, all eight subscriptions log, state reads work, update is empty, no errors.