mlua-periphery 1.2.4

A Rust-native implementation of lua-periphery for mlua.
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use mlua::{Error, Lua, Table, UserData, UserDataMethods};

#[derive(Clone)]
struct Gpio {}

impl UserData for Gpio {
    fn add_methods<M: UserDataMethods<Self>>(methods: &mut M) {
        methods.add_method("close", handle);
        methods.add_method("poll", handle);
        methods.add_method("read", handle);
        methods.add_method("read_event", handle);
        methods.add_method("write", handle);
    }
}

pub fn preload(lua: &Lua) -> Result<(), Error> {
    // Configure module table
    let module = lua.create_table()?;

    // Configure module metatable
    let metatable = lua.create_table()?;
    metatable.raw_set(
        "__call",
        lua.create_function(|_lua, _args: mlua::MultiValue| Ok(Gpio {}))?,
    )?;
    module.set_metatable(Some(metatable))?;

    // Preload module
    let globals = lua.globals();
    let package: Table = globals.get("package")?;
    let loaded: Table = package.get("loaded")?;
    loaded.set("periphery.GPIO", module)?;

    Ok(())
}

fn handle(_lua: &Lua, _gpio: &Gpio, _args: mlua::MultiValue) -> Result<(), Error> {
    Err(Error::RuntimeError(
        "GPIO support is unavailable for this platform".to_string(),
    ))
}

#[cfg(test)]
mod tests {
    use mlua::Lua;
    use std::error::Error;

    #[test]
    fn preload() -> Result<(), Box<dyn Error>> {
        let lua = Lua::new();
        super::preload(&lua)?;
        lua.load("local GPIO = require('periphery.GPIO')").exec()?;
        Ok(())
    }
}