Sand-Boxing – Block Access to External Data
Rhai is sand-boxed so a script can never read from outside its own environment.
Engine created non-
mut cannot mutate any state, including itself
(and therefore it is also re-entrant).
It is highly recommended that
Engine’s be created immutable as much as possible.
let mut engine = Engine::new(); // Use the fluent API to configure an 'Engine' engine.register_get("field", get_field) .register_set("field", set_field) .register_fn("do_work", action); // Then turn it into an immutable instance let engine = engine; // 'engine' is immutable...
How does a sand-boxed, immutable
Engine control the external environment?
This is necessary in order to use Rhai as a dynamic control layer over a Rust core system.
There are two general patterns, both involving wrapping the external system
in a shared, interior-mutated object (e.g.
Control Layer pattern.
Singleton Command Object pattern.