nif-scaffold

name	nif-scaffold
description	Generate Rustler NIF boilerplate for a new native module. Creates Cargo.toml, lib.rs, and Elixir wrapper module.
user-invocable	true
allowed-tools	Read, Write, Edit, Bash, Glob
argument-hint	<app-name> <nif-name>

NIF Scaffold Generator

Create a new Rust NIF module for app $0 named $1.

Steps

1. Validate arguments:

   • $0 must be an existing umbrella app (eth_core, eth_crypto, eth_net, eth_storage, eth_rpc)
   • $1 should be snake_case (the NIF crate name)

2. Read the app's mix.exs to understand current dependencies and compilers

3. Create the Rust NIF structure:

   apps/$0/native/$1/
   ├── Cargo.toml
   └── src/
       └── lib.rs
   

4. Cargo.toml template:

   • [package] with name = "$1", edition = "2021"
   • [lib] with crate-type = ["cdylib"]
   • [dependencies] with rustler = "0.34"
   • Add domain-specific deps based on NIF purpose

5. lib.rs template:

   • #[rustler::nif] example function
   • rustler::init! macro
   • Comments for DirtyCpu scheduling pattern

6. Create Elixir wrapper module at apps/$0/lib/$0/$1.ex:

   • use Rustler, otp_app: :$0, crate: "$1"
   • Placeholder NIF functions with :erlang.nif_error/1
   • @moduledoc and @spec for each function

7. Update apps/$0/mix.exs:

   • Add :rustler to deps if not present
   • Add rustler_crates config
   • Add :rustler to compilers list

8. Verify the scaffold compiles: cd apps/$0 && mix compile