Struct Cell 

pub struct Cell { /* private fields */ }

A shared, mutable cell holding a single Value.

The cell is the base mutation handle: a cloneable, reference-counted slot whose set requires standard_mutate_capability. Reads are always allowed; writes fail closed without the capability.

Examples

use std::sync::Arc;
use sim_kernel::{Cx, DefaultFactory, NoopEvalPolicy};
use sim_lib_mutation::{Cell, standard_mutate_capability};

let mut cx = Cx::new(Arc::new(NoopEvalPolicy), Arc::new(DefaultFactory));
let old = cx.factory().string("old".to_owned()).unwrap();
let cell = Cell::new(old);

// Writing fails closed until the mutate capability is granted.
let new = cx.factory().string("new".to_owned()).unwrap();
assert!(cell.set(&mut cx, new).is_err());

cx.grant(standard_mutate_capability());
let new = cx.factory().string("new".to_owned()).unwrap();
cell.set(&mut cx, new).unwrap();

Implementations

impl Cell

pub fn new(value: Value) -> Self

Create a cell initialized to value.

pub fn get(&self) -> Result<Value>

Return a clone of the current value. Reads need no capability.

pub fn set(&self, cx: &mut Cx, value: Value) -> Result<()>

Overwrite the cell with value, requiring standard_mutate_capability.

Trait Implementations

impl Clone for Cell

fn clone(&self) -> Cell

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Object for Cell

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<(), Error>

Emit the object’s claims matching pattern into sink.

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

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

impl ObjectCompat for Cell

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

Class object this value belongs to; defaults to nil.

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 + 'static)>

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_thunk(&self) -> Option<&dyn Thunk>

Thunk view, if the object is a deferred computation.

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

List view, if the object is a list value.

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

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

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

Directory view, if the object is a directory.

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

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

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

Truthiness of the object; defaults to true.

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

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

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

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