Scope

Struct Scope 

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pub struct Scope<'scope, 'env: 'scope> { /* private fields */ }
Expand description

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.

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

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pub fn create_function<F, A, R>(&'scope self, func: F) -> Result<Function>
where F: Fn(&Lua, A) -> Result<R> + '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.

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pub fn create_function_mut<F, A, R>(&'scope self, func: F) -> Result<Function>
where F: FnMut(&Lua, A) -> Result<R> + '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.

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

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

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

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

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

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

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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)));

Auto Trait Implementations§

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impl<'scope, 'env> !Freeze for Scope<'scope, 'env>

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impl<'scope, 'env> !RefUnwindSafe for Scope<'scope, 'env>

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impl<'scope, 'env> !Send for Scope<'scope, 'env>

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impl<'scope, 'env> !Sync for Scope<'scope, 'env>

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

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impl<'scope, 'env> !UnwindSafe for Scope<'scope, 'env>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.