Struct Scope 

pub struct Scope<'scope, 'env>
where
    'env: 'scope,
{
    lua: LuaGuard,
    destructors: Destructors<'env>,
    user_destructors: UserDestructors<'env>,
    _scope_invariant: PhantomData<&'scope mut &'scope ()>,
    _env_invariant: PhantomData<&'env mut &'env ()>,
}

Constructed by the Lua::scope method, allows temporarily creating Lua userdata and callbacks that are not required to be Send or 'static.

See Lua::scope for more details.

Fields

lua: LuaGuard

destructors: Destructors<'env>

user_destructors: UserDestructors<'env>

_scope_invariant: PhantomData<&'scope mut &'scope ()>

_env_invariant: PhantomData<&'env mut &'env ()>

Implementations

impl<'scope, 'env> Scope<'scope, 'env>

where 'env: 'scope,

pub fn create_function<F, A, R>( &'scope self, func: F, ) -> Result<Function, Error>

where F: Fn(&Lua, A) -> Result<R, Error> + 'scope, A: FromLuaMulti, R: IntoLuaMulti,

Wraps a Rust function or closure, creating a callable Lua function handle to it.

This is a version of Lua::create_function that creates a callback which expires on scope drop. See Lua::scope for more details.

pub fn create_function_mut<F, A, R>( &'scope self, func: F, ) -> Result<Function, Error>

where F: FnMut(&Lua, A) -> Result<R, Error> + 'scope, A: FromLuaMulti, R: IntoLuaMulti,

Wraps a Rust mutable closure, creating a callable Lua function handle to it.

This is a version of Lua::create_function_mut that creates a callback which expires on scope drop. See Lua::scope and Scope::create_function for more details.

pub fn create_userdata_ref<T>( &'scope self, data: &'env T, ) -> Result<AnyUserData, Error>

where T: UserData + 'static,

Creates a Lua userdata object from a reference to custom userdata type.

This is a version of Lua::create_userdata that creates a userdata which expires on scope drop, and does not require that the userdata type be Send. This method takes non-’static reference to the data. See Lua::scope for more details.

Userdata created with this method will not be able to be mutated from Lua.

pub fn create_userdata_ref_mut<T>( &'scope self, data: &'env mut T, ) -> Result<AnyUserData, Error>

where T: UserData + 'static,

Creates a Lua userdata object from a mutable reference to custom userdata type.

This is a version of Lua::create_userdata that creates a userdata which expires on scope drop, and does not require that the userdata type be Send. This method takes non-’static mutable reference to the data. See Lua::scope for more details.

pub fn create_any_userdata_ref<T>( &'scope self, data: &'env T, ) -> Result<AnyUserData, Error>

where T: 'static,

Creates a Lua userdata object from a reference to custom Rust type.

This is a version of Lua::create_any_userdata that creates a userdata which expires on scope drop, and does not require that the Rust type be Send. This method takes non-’static reference to the data. See Lua::scope for more details.

Userdata created with this method will not be able to be mutated from Lua.

pub fn create_any_userdata_ref_mut<T>( &'scope self, data: &'env mut T, ) -> Result<AnyUserData, Error>

where T: 'static,

Creates a Lua userdata object from a mutable reference to custom Rust type.

This is a version of Lua::create_any_userdata that creates a userdata which expires on scope drop, and does not require that the Rust type be Send. This method takes non-’static mutable reference to the data. See Lua::scope for more details.

pub fn create_userdata<T>(&'scope self, data: T) -> Result<AnyUserData, Error>

where T: UserData + 'env,

Creates a Lua userdata object from a custom userdata type.

This is a version of Lua::create_userdata that creates a userdata which expires on scope drop, and does not require that the userdata type be Send or 'static. See Lua::scope for more details.

The main limitation that comes from using non-’static userdata is that the produced userdata will no longer have a TypeId associated with it, because TypeId can only work for 'static types. This means that it is impossible, once the userdata is created, to get a reference to it back out of an AnyUserData handle. This also implies that the “function” type methods that can be added via UserDataMethods (the ones that accept AnyUserData as a first parameter) are vastly less useful. Also, there is no way to re-use a single metatable for multiple non-’static types, so there is a higher cost associated with creating the userdata metatable each time a new userdata is created.

pub fn create_any_userdata<T>( &'scope self, data: T, register: impl FnOnce(&mut UserDataRegistry<T>), ) -> Result<AnyUserData, Error>

where T: 'env,

Creates a Lua userdata object from a custom Rust type.

Since the Rust type is not required to be static and implement UserData trait, you need to provide a function to register fields or methods for the object.

See also Scope::create_userdata for more details about non-static limitations.

pub fn add_destructor(&'scope self, destructor: impl FnOnce() + 'env)

Adds a destructor function to be run when the scope ends.

This functionality is useful for cleaning up any resources after the scope ends.

Example

let lua = Lua::new();
let ud = lua.create_any_userdata(String::from("hello"))?;
lua.scope(|scope| {
    scope.add_destructor(|| {
        _ = ud.take::<String>();
    });
    // Run the code that uses `ud` here
   Ok(())
})?;
assert!(matches!(ud.borrow::<String>(), Err(Error::UserDataDestructed)));