Crate rhai[−][src]

Expand description

Rhai - embedded scripting for Rust

Rhai is a tiny, simple and very fast embedded scripting language for Rust that gives you a safe and easy way to add scripting to your applications. It provides a familiar syntax based on JavaScript and Rust and a simple Rust interface. Here is a quick example.

First, the contents of my_script.rhai:

// Brute force factorial function
fn factorial(x) {
    if x == 1 { return 1; }
    x * factorial(x - 1)
}

// Calling an external function 'compute'
compute(factorial(10))

And the Rust part:

use rhai::{Engine, EvalAltResult, RegisterFn};

fn main() -> Result<(), Box<EvalAltResult>>
{
    // Define external function
    fn compute_something(x: i64) -> bool {
        (x % 40) == 0
    }

    // Create scripting engine
    let mut engine = Engine::new();

    // Register external function as 'compute'
    engine.register_fn("compute", compute_something);

    assert_eq!(
        // Evaluate the script, expects a 'bool' return
        engine.eval_file::<bool>("my_script.rhai".into())?,
        true
    );

    Ok(())
}

Optional features

Feature	Description
`unchecked`	Exclude arithmetic checking (such as overflows and division by zero). Beware that a bad script may panic the entire system!
`no_function`	Disable script-defined functions if not needed.
`no_module`	Disable loading external modules if not needed.
`no_index`	Disable arrays and indexing features if not needed.
`no_object`	Disable support for custom types and objects.
`no_float`	Disable floating-point numbers and math if not needed.
`no_optimize`	Disable the script optimizer.
`only_i32`	Set the system integer type to `i32` and disable all other integer types. `INT` is set to `i32`.
`only_i64`	Set the system integer type to `i64` and disable all other integer types. `INT` is set to `i64`.
`no_std`	Build for `no-std`. Notice that additional dependencies will be pulled in to replace `std` features.
`sync`	Restrict all values types to those that are `Send + Sync`. Under this feature, `Engine`, `Scope` and `AST` are all `Send + Sync`.
`internals`	Expose internal data structures (beware they may be volatile from version to version).