Struct boa::builtins::function::Captures

pub struct Captures(_);

Wrapper for Box<dyn NativeObject + Clone> that allows passing additional captures through a Copy closure.

Any type implementing Trace + Any + Debug + Clone can be used as a capture context, so you can pass e.g. a String, a tuple or even a full struct.

You can downcast to any type and handle the fail case as you like with downcast_ref and downcast_mut, or you can use try_downcast_ref and try_downcast_mut to automatically throw a TypeError if the downcast fails.

Implementations

impl Captures

pub fn downcast_ref<T>(&self) -> Option<&T> where
    T: NativeObject + Clone, 

Downcasts Captures to the specified type, returning a reference to the downcasted type if successful or None otherwise.

pub fn downcast_mut<T>(&mut self) -> Option<&mut T> where
    T: NativeObject + Clone, 

Mutably downcasts Captures to the specified type, returning a mutable reference to the downcasted type if successful or None otherwise.

pub fn try_downcast_ref<T>(&self, context: &mut Context) -> JsResult<&T> where
    T: NativeObject + Clone, 

Downcasts Captures to the specified type, returning a reference to the downcasted type if successful or a TypeError otherwise.

pub fn try_downcast_mut<T>(&mut self, context: &mut Context) -> JsResult<&mut T> where
    T: NativeObject + Clone, 

Downcasts Captures to the specified type, returning a reference to the downcasted type if successful or a TypeError otherwise.

Trait Implementations

impl Clone for Captures

fn clone(&self) -> Captures

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Captures

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

Formats the value using the given formatter.

impl Drop for Captures

fn drop(&mut self)

Executes the destructor for this type.

impl Finalize for Captures

fn finalize(&self)

impl Trace for Captures

unsafe fn trace(&self)

Marks all contained Gcs.

unsafe fn root(&self)

Increments the root-count of all contained Gcs.

unsafe fn unroot(&self)

Decrements the root-count of all contained Gcs.

fn finalize_glue(&self)

Runs Finalize::finalize() on this object and all contained subobjects