Enum UdValue 

pub enum UdValue {
    Nil,
    Boolean(bool),
    Integer(i64),
    Number(f64),
    Str(String),
    Function(CFunction),
    UserdataRef(*const dyn Any),
    UserdataOwned(Box<dyn UserDataTrait>),
}

Intermediate value type for userdata field/method returns.

Since LuaValue requires GC-allocated strings, trait methods return UdValue which the VM converts to proper LuaValue (interning strings as needed).

Variants

Nil

Boolean(bool)

Integer(i64)

Number(f64)

Str(String)

A Rust string — will be interned by the VM when converting to LuaValue

Function(CFunction)

A light C function — used for returning methods from get_field

UserdataRef(*const dyn Any)

Borrowed reference to another userdata’s inner value (as operand in arithmetic/comparison). Valid only during the trait method call. Use UdValue::as_userdata_ref to safely downcast.

UserdataOwned(Box<dyn UserDataTrait>)

Owned userdata value (as return from arithmetic trait methods). The VM allocates this as a new GC-managed userdata.

Implementations

impl UdValue

pub fn is_nil(&self) -> bool

pub fn as_userdata_ref<T: 'static>(&self) -> Option<&T>

Try to downcast a UserdataRef operand to a concrete type.

Returns Some(&T) if the operand is a userdata of type T. This is the primary way to access the other operand in arithmetic trait methods when both operands are userdata.

Safety

The returned reference borrows from the GC-managed userdata on the Lua stack. It is valid for the duration of the trait method call.

Example (generated by derive macro)

fn lua_add(&self, other: &UdValue) -> Option<UdValue> {
    if let Some(o) = other.as_userdata_ref::<Vec2>() {
        Some(UdValue::from_userdata(Vec2 { x: self.x + o.x, y: self.y + o.y }))
    } else {
        None
    }
}

pub fn from_userdata<T: UserDataTrait>(value: T) -> Self

Wrap a value that implements UserDataTrait into an owned UdValue.

Use this as the return value from arithmetic trait methods when the result is a new userdata (e.g., Vec2 + Vec2 → Vec2).

impl UdValue

pub fn to_bool(&self) -> bool

Extract as bool. Follows Lua truthiness: nil and false are false, everything else is true.

pub fn to_integer(&self) -> Option<i64>

Extract as i64 (with optional float→int coercion).

pub fn to_number(&self) -> Option<f64>

Extract as f64 (with optional int→float coercion).

pub fn to_str(&self) -> Option<&str>

Extract as string reference.

Trait Implementations

impl Clone for UdValue

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for UdValue

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

Formats the value using the given formatter.

impl Display for UdValue

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

Formats the value using the given formatter.

impl From<&str> for UdValue

fn from(s: &str) -> Self

Converts to this type from the input type.

impl<T: Into<UdValue>> From<Option<T>> for UdValue

fn from(opt: Option<T>) -> Self

Converts to this type from the input type.

impl From<String> for UdValue

fn from(s: String) -> Self

Converts to this type from the input type.

impl From<bool> for UdValue

fn from(b: bool) -> Self

Converts to this type from the input type.

impl From<f32> for UdValue

fn from(n: f32) -> Self

Converts to this type from the input type.

impl From<f64> for UdValue

fn from(n: f64) -> Self

Converts to this type from the input type.

impl From<i32> for UdValue

fn from(i: i32) -> Self

Converts to this type from the input type.

impl From<i64> for UdValue

fn from(i: i64) -> Self

Converts to this type from the input type.