Struct ThunkObject 

pub struct ThunkObject { /* private fields */ }

A memoizing call-by-need thunk: evaluated at most once, then cached.

Used by NeedPolicy: the first successful force records the value for all later forces; a failed force leaves the thunk pending so it can be retried.

Implementations

impl ThunkObject

pub fn new(input: Expr, env: Env) -> Self

Creates a pending thunk capturing input and the environment env.

Trait Implementations

impl Object for ThunkObject

fn display(&self, _cx: &mut Cx) -> Result<String>

Render the object as a human-readable display string.

fn as_any(&self) -> &dyn Any

Expose the object for Rust downcasting.

fn header(&self) -> &ObjectHeader

Identity and trust header for the object; defaults to the shared anonymous header.

fn op(&self, _key: &OpKey) -> Option<&dyn Op>

Resolve the operation registered under key, if any.

fn claims( &self, _cx: &mut Cx, _pattern: &ClaimPattern, _sink: &mut dyn ClaimSink, ) -> Result<()>

Emit the object’s claims matching pattern into sink.

fn snapshot(&self, _cx: &mut Cx) -> Result<Option<Datum>>

Optional content-addressable snapshot of the object’s state.

impl ObjectCompat for ThunkObject

fn class(&self, cx: &mut Cx) -> Result<Value>

Class object this value belongs to; defaults to nil.

fn as_expr(&self, cx: &mut Cx) -> Result<Expr>

Expression form of the object; defaults to an opaque extension node.

fn as_thunk(&self) -> Option<&dyn Thunk>

Thunk view, if the object is a deferred computation.

fn as_callable(&self) -> Option<&dyn Callable>

Callable view, if the object can be invoked.

fn as_class(&self) -> Option<&dyn Class>

Class view, if the object is a class.

fn as_shape(&self) -> Option<&dyn Shape>

Shape view, if the object is a shape.

fn as_object_encoder(&self) -> Option<&dyn ObjectEncode>

Object-encoder view, if the object encodes other objects.

fn as_read_constructor(&self) -> Option<&dyn ReadConstructor>

Read-constructor view, if the object decodes data forms.

fn as_number_domain(&self) -> Option<&dyn NumberDomain>

Number-domain view, if the object is a number domain.

fn as_number_value(&self) -> Option<&dyn NumberValue>

Number-value view, if the object is a domain number.

fn as_eval_fabric(&self) -> Option<&dyn EvalFabric>

Eval-fabric view, if the object is a distributed eval surface.

fn as_stream(&self) -> Option<&dyn Stream>

Stream view, if the object is a stream.

fn as_sequence(&self) -> Option<&dyn Sequence>

Sequence view, if the object is a sequence.

fn as_list(&self) -> Option<&dyn ListValue>

List view, if the object is a list value.

fn as_table_impl(&self) -> Option<&dyn Table>

Table-implementation view, if the object is a table.

fn as_dir(&self) -> Option<&dyn Dir>

Directory view, if the object is a directory.

fn truth(&self, _cx: &mut Cx) -> Result<bool>

Truthiness of the object; defaults to true.

fn publish_shape_satisfaction_claims( &self, _cx: &mut Cx, _shape: &Ref, ) -> Result<bool>

Publish claims asserting that the object satisfies shape; returns whether any were published.

fn as_table(&self, cx: &mut Cx) -> Result<Value>

Project the object into a table value; the default exposes its display.

impl Thunk for ThunkObject

fn force(&self, cx: &mut Cx, _demand: Demand) -> Result<Value>

Forces the delayed computation, returning its value.