Struct AnyUserData

pub struct AnyUserData(/* private fields */);

Handle to an internal Lua userdata for any type that implements UserData.

Similar to std::any::Any, this provides an interface for dynamic type checking via the is and borrow methods.

Note

This API should only be used when necessary. Implementing UserData already allows defining methods which check the type and acquire a borrow behind the scenes.

Implementations

impl AnyUserData

pub fn is<T>(&self) -> bool

where T: 'static,

Checks whether the type of this userdata is T.

pub fn borrow<T>(&self) -> Result<UserDataRef<T>, Error>

where T: 'static,

Borrow this userdata immutably if it is of type T.

Errors

Returns a UserDataBorrowError if the userdata is already mutably borrowed. Returns a DataTypeMismatch if the userdata is not of type T or if it’s scoped.

pub fn borrow_scoped<T, R>(&self, f: impl FnOnce(&T) -> R) -> Result<R, Error>

where T: 'static,

Borrow this userdata immutably if it is of type T, passing the borrowed value to the closure.

This method is the only way to borrow scoped userdata (created inside Lua::scope).

pub fn borrow_mut<T>(&self) -> Result<UserDataRefMut<T>, Error>

where T: 'static,

Borrow this userdata mutably if it is of type T.

Errors

Returns a UserDataBorrowMutError if the userdata cannot be mutably borrowed. Returns a UserDataTypeMismatch if the userdata is not of type T or if it’s scoped.

pub fn borrow_mut_scoped<T, R>( &self, f: impl FnOnce(&mut T) -> R, ) -> Result<R, Error>

where T: 'static,

Borrow this userdata mutably if it is of type T, passing the borrowed value to the closure.

This method is the only way to borrow scoped userdata (created inside Lua::scope).

pub fn take<T>(&self) -> Result<T, Error>

where T: 'static,

Takes the value out of this userdata.

Sets the special “destructed” metatable that prevents any further operations with this userdata.

Keeps associated user values unchanged (they will be collected by Lua’s GC).

pub fn destroy(&self) -> Result<(), Error>

Destroys this userdata.

This is similar to AnyUserData::take, but it doesn’t require a type.

This method works for non-scoped userdata only.

pub fn set_user_value(&self, v: impl IntoLua) -> Result<(), Error>

Sets an associated value to this AnyUserData.

The value may be any Lua value whatsoever, and can be retrieved with user_value.

This is the same as calling set_nth_user_value with n set to 1.

pub fn user_value<V>(&self) -> Result<V, Error>

where V: FromLua,

Returns an associated value set by set_user_value.

This is the same as calling nth_user_value with n set to 1.

pub fn set_nth_user_value(&self, n: usize, v: impl IntoLua) -> Result<(), Error>

Sets an associated nth value to this AnyUserData.

The value may be any Lua value whatsoever, and can be retrieved with nth_user_value. n starts from 1 and can be up to 65535.

This is supported for all Lua versions using a wrapping table.

pub fn nth_user_value<V>(&self, n: usize) -> Result<V, Error>

where V: FromLua,

Returns an associated nth value set by set_nth_user_value.

n starts from 1 and can be up to 65535.

This is supported for all Lua versions using a wrapping table.

pub fn set_named_user_value( &self, name: &str, v: impl IntoLua, ) -> Result<(), Error>

Sets an associated value to this AnyUserData by name.

The value can be retrieved with named_user_value.

pub fn named_user_value<V>(&self, name: &str) -> Result<V, Error>

where V: FromLua,

Returns an associated value by name set by set_named_user_value.

pub fn metatable(&self) -> Result<UserDataMetatable, Error>

Returns a metatable of this AnyUserData.

Returned UserDataMetatable object wraps the original metatable and provides safe access to its methods.

For T: 'static returned metatable is shared among all instances of type T.

pub fn to_pointer(&self) -> *const c_void

Converts this userdata to a generic C pointer.

There is no way to convert the pointer back to its original value.

Typically this function is used only for hashing and debug information.

impl AnyUserData

pub fn wrap<T>(data: T) -> impl IntoLua

where T: MaybeSend + 'static,

Wraps any Rust type, returning an opaque type that implements IntoLua trait.

This function uses Lua::create_any_userdata under the hood.

Trait Implementations

impl Clone for AnyUserData

fn clone(&self) -> AnyUserData

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AnyUserData

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl FromLua for AnyUserData

fn from_lua(value: Value, _: &Lua) -> Result<AnyUserData, Error>

Performs the conversion.

impl IntoLua for &AnyUserData

fn into_lua(self, _: &Lua) -> Result<Value, Error>

Performs the conversion.

impl IntoLua for AnyUserData

fn into_lua(self, _: &Lua) -> Result<Value, Error>

Performs the conversion.

impl ObjectLike for AnyUserData

fn get<V>(&self, key: impl IntoLua) -> Result<V, Error>

where V: FromLua,

Gets the value associated to key from the object, assuming it has __index metamethod.

fn set(&self, key: impl IntoLua, value: impl IntoLua) -> Result<(), Error>

Sets the value associated to key in the object, assuming it has __newindex metamethod.

fn call<R>(&self, args: impl IntoLuaMulti) -> Result<R, Error>

where R: FromLuaMulti,

Calls the object as a function assuming it has __call metamethod.

fn call_method<R>( &self, name: &str, args: impl IntoLuaMulti, ) -> Result<R, Error>

where R: FromLuaMulti,

Gets the function associated to key name from the object and calls it, passing the object itself along with args as function arguments.

fn call_function<R>( &self, name: &str, args: impl IntoLuaMulti, ) -> Result<R, Error>

where R: FromLuaMulti,

Gets the function associated to key name from the object and calls it, passing args as function arguments.

fn to_string(&self) -> Result<String, Error>

Converts the object to a string in a human-readable format.

impl PartialEq for AnyUserData

fn eq(&self, other: &AnyUserData) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for AnyUserData