Struct VariantConstructor 

pub struct VariantConstructor { /* private fields */ }

A callable builder for one ADT variant.

Calling a constructor checks each argument against the variant’s field Shapes and produces a TaggedValue. It is also a runtime Object (callable, table-reflectable) so it can be installed as a value.

Implementations

impl VariantConstructor

pub fn new(adt: Symbol, variant: VariantDeclaration) -> Self

Builds a constructor for variant within ADT adt.

pub fn adt(&self) -> &Symbol

Returns the owning ADT name symbol.

pub fn variant(&self) -> &Symbol

Returns the variant tag symbol.

pub fn fields(&self) -> &[PatternField]

Returns the variant fields in declaration order.

pub fn variant_shape(&self) -> VariantShape

Returns the kernel VariantShape that matches this variant.

pub fn shape(&self) -> Arc<dyn Shape>

Returns the variant matcher as a boxed kernel Shape.

pub fn construct(&self, cx: &mut Cx, fields: Vec<Value>) -> Result<Value>

Builds a TaggedValue from the supplied field values.

Errors

Returns an error if the arity is wrong or a field Shape rejects its value.

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

Wraps the constructor itself as a callable runtime Value.

Trait Implementations

impl Callable for VariantConstructor

fn call(&self, cx: &mut Cx, args: Args) -> Result<Value>

Invoke the callable with already-evaluated, checked Args.

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

Optional shape describing the accepted argument list, for browsing.

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

Optional shape describing the call result, for browsing.

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

Invoke the callable on raw, unevaluated argument expressions.

impl Clone for VariantConstructor

fn clone(&self) -> VariantConstructor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Object for VariantConstructor

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 VariantConstructor

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

Callable view, if the object can be invoked.

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

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

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

Class object this value belongs to; defaults to nil.

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.