rustler-bindings

name	rustler-bindings
description	Rustler conventions for building Elixir NIFs from a Rust core: nif macros, tagged {:ok,_}/{:error,_} tuples, dirty schedulers, ResourceArc state, NifStruct derives, and mix compile. Load when generating or reviewing Rustler Elixir NIF bindings for a Rust library.

• Use #[rustler::nif] for Elixir NIF functions. Use #[module = "Elixir.ModuleName"] for module naming.
• Return tagged tuples: {:ok, value} / {:error, reason}. Use Rustler encoders/decoders for type mapping.
• Use rustler::Error for NIF error handling. Map Rust errors to descriptive Elixir error tuples.
• Keep NIF functions fast (<1ms) to avoid scheduler issues. Use #[rustler::nif(schedule = "DirtyCpu")] for long operations.
• Build with mix compile (Rustler compiler). Test from Elixir using ExUnit.
• Use ResourceArc<T> for sharing Rust state across NIF calls. Implement Drop for cleanup.
• Use #[derive(NifStruct)] and #[derive(NifUnitEnum)] for Elixir-compatible types.
• Keep Elixir NIF wrapper thin — business logic in Rust, Elixir provides functional API.
• Handle binary data with Binary and OwnedBinary types.
• Anti-patterns: no panics in NIFs (crashes the BEAM VM), no blocking the scheduler, no I/O in NIFs.