Struct PhantomVar 

pub struct PhantomVar<T>(/* private fields */)
where
    T: GodotType + Var;

A zero-sized type for creating a property without a backing field, accessible only through custom getter/setter functions.

This must be used in a struct deriving GodotClass and requires that the field has an explicit #[var] attribute with a custom getter, and optionally a custom setter. Both getter and setter operate on the specified type T.

(Note that write-only properties, with a setter but not a getter, are not currently supported. Godot doesn’t fully support them either, silently returning null instead of an error if the property is being read.)

Example

Suppose you have a field text whose value you want to keep as a Rust String rather than a Godot GString, accepting the performance penalty for conversions whenever the property is accessed from Godot:

#[derive(GodotClass)]
#[class(init)]
struct Banner {
    #[var(get = get_text, set = set_text)]
    text: PhantomVar<GString>,

    text_string: String,
}

#[godot_api]
impl Banner {
    #[func]
    fn get_text(&self) -> GString {
        GString::from(&self.text_string)
    }

    #[func]
    fn set_text(&mut self, text: GString) {
        self.text_string = String::from(&text);
    }
}

This field can now be accessed from GDScript as banner.text.

Trait Implementations

impl<T> Clone for PhantomVar<T>

where T: GodotType + Var,

fn clone(&self) -> PhantomVar<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Debug for PhantomVar<T>

where T: GodotType + Var,

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

Formats the value using the given formatter.

impl<T> Default for PhantomVar<T>

where T: GodotType + Var,

fn default() -> PhantomVar<T>

Returns the “default value” for a type.

impl<T> Export for PhantomVar<T>

where T: GodotType + Var + Export,

fn export_hint() -> PropertyHintInfo

The export info to use for an exported field of this type, if no other export info is specified.

impl<T> GodotConvert for PhantomVar<T>

where T: GodotType + Var,

type Via = T

The type through which Self is represented in Godot.

impl<T> Hash for PhantomVar<T>

where T: GodotType + Var,

fn hash<H>(&self, _state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T> Ord for PhantomVar<T>

where T: GodotType + Var,

fn cmp(&self, _other: &PhantomVar<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<T> PartialEq for PhantomVar<T>

where T: GodotType + Var,

fn eq(&self, _other: &PhantomVar<T>) -> 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<T> PartialOrd for PhantomVar<T>

where T: GodotType + Var,

fn partial_cmp(&self, other: &PhantomVar<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T> Var for PhantomVar<T>

where T: GodotType + Var,

fn get_property(&self) -> <PhantomVar<T> as GodotConvert>::Via

fn set_property(&mut self, _value: <PhantomVar<T> as GodotConvert>::Via)

fn var_hint() -> PropertyHintInfo

Specific property hints, only override if they deviate from GodotType::property_info, e.g. for enums/newtypes.

impl<T> Copy for PhantomVar<T>

where T: GodotType + Var,

impl<T> Eq for PhantomVar<T>

where T: GodotType + Var,

impl<T> Send for PhantomVar<T>

where T: GodotType + Var,

impl<T> Sync for PhantomVar<T>

where T: GodotType + Var,