Calling Ruby from Rust

To call a function defined in Ruby

def on_update
end

We need to acquire RubyRuntime resource within a bevy system. Then we will be able to call call_fn on it, providing the name of the function to call, RubyScriptData that has been automatically attached to entity after an entity with script attached has been spawned and its script evaluated, the entity and optionally some arguments.

#![allow(unused)]
fn main() {
extern crate bevy;
extern crate bevy_scriptum;

use bevy::prelude::*;
use bevy_scriptum::prelude::*;
use bevy_scriptum::runtimes::ruby::prelude::*;

fn call_ruby_on_update_from_rust(
    mut scripted_entities: Query<(Entity, &mut RubyScriptData)>,
    scripting_runtime: ResMut<RubyRuntime>,
) {
    for (entity, mut script_data) in &mut scripted_entities {
        // calling function named `on_update` defined in Ruby script
        scripting_runtime
            .call_fn("on_update", &mut script_data, entity, ())
            .unwrap();
    }
}
}

We can also pass some arguments by providing a tuple or Vec as the last call_fn argument.

#![allow(unused)]
fn main() {
extern crate bevy;
extern crate bevy_scriptum;

use bevy::prelude::*;
use bevy_scriptum::prelude::*;
use bevy_scriptum::runtimes::ruby::prelude::*;

fn call_ruby_on_update_from_rust(
    mut scripted_entities: Query<(Entity, &mut RubyScriptData)>,
    scripting_runtime: ResMut<RubyRuntime>,
) {
    for (entity, mut script_data) in &mut scripted_entities {
        scripting_runtime
            .call_fn("on_update", &mut script_data, entity, (123, String::from("hello")))
            .unwrap();
    }
}
}

They will be passed to on_update Ruby function

def on_update(a, b)
    puts(a) # 123
    puts(b) # hello
end