Crate reflow_pack_macro 

#[reflow_pack] — wraps a user function fn(&mut PackHost) with the entrypoints the loader expects a pack to export.

Two ABIs, one source crate

Pack source crates produce two distinct binary shapes from the same Rust:

• Native cdylib (dlopen / LoadLibrary). Loader passes a *mut PackHostVtable through the standard C ABI; the pack’s register function fills it with template factories and returns a status.
• Browser wasm (WebAssembly.instantiate). The pack wasm imports a single JS callback (__reflow_pack_register_template), and exports a no-arg registration function the JS loader calls right after instantiation. The pack walks the user’s register function once, calling the JS import for each template, then stashes the factories in a process-static table keyed by an integer id. JS hands those ids back to __reflow_pack_create_actor(id) whenever the runtime needs a fresh actor instance.

Both ABIs route through the same user-written register function; the macro emits whichever entrypoints are appropriate for the target. See crates/reflow_pack_loader/src/lib.rs for the native loader and sdk/node/reflow.browser.mjs::loadPack for the browser one.

Attribute Macros

reflow_pack

Mark a function as the pack’s registration entrypoint.