@caputchin/replay-wasm

Generic host glue for a Caputchin headless WASM replay artifact. A game whose sim compiles to WASM (the strongest determinism path - the same .wasm runs in the browser and on the server) uses this kit to turn the module into the one conforming run(seed, config, trace) the platform replays.

It pairs with the caputchin-replay-rs authoring crate (which emits the cap_alloc / cap_run C-ABI this kit marshals into) and the @caputchin/replay-contract types.

What it provides

• runWithModule(module, seed, configInts, trace) - instantiate a precompiled WebAssembly.Module, marshal the seed / config / trace across the cap_alloc / cap_run linear-memory C-ABI, and read back the Verdict. A game's run is typically one line over this.
• inflateWasm(...) - decode a gzip + base64 INLINE wasm payload. A replayable artifact often inlines its .wasm (the replay isolate forbids runtime byte-compilation and network fetch), and this inflates it for instantiation.
• toBytes(...) - the byte-marshalling helper the above share.
• Re-exports the contract types (Seed, Verdict, RunFn) for one import site.

Usage

import { runWithModule } from '@caputchin/replay-wasm';
import type { RunFn } from '@caputchin/replay-contract';
import wasmModule from './sim.wasm'; // precompiled module (loader/build provides it)

export const run: RunFn = (seed, config, trace) =>
  runWithModule(wasmModule, seed, configToInts(config), trace);

The WASM module must export the cap_alloc / cap_run C-ABI (the caputchin-replay-rs crate generates it from a deterministic Rust sim).