Struct Cell

pub struct Cell<A> {
    pub impl_: Cell<A>,
}

Represents a value of type A that changes over time.

In other Functional Reactive Programming (FRP) systems this is also called a behavior, property, or a signal. A Cell should be used for modeling any pieces of mutable state in an FRP application.

Fields

impl_: Cell<A>

Implementations

impl<A: Clone + Send + 'static> Cell<A>

pub fn new(sodium_ctx: &SodiumCtx, value: A) -> Cell<A>

Create a Cell with a constant value.

pub fn sample(&self) -> A

Sample the Cell’s current value.

Cell::sample may be used in the functions passed to primitives that apply them to Streams, including Stream::map, Stream::snapshot, Stream::filter, and Stream::merge.

When called within a function passed to Stream::map using sample is equivalent to snapshotting this Cell with that Stream.

pub fn sample_lazy(&self) -> Lazy<A>

Sample the Cell’s current value lazily.

When it is necessary to use sample while implementing more general abstractions, sample_lazy should be preferred in case a CellLoop is passed rather than a Cell.

See Cell::sample for more details.

pub fn updates(&self) -> Stream<A>

Return a Stream that gives the updates/steps for a Cell.

Important

This is an operational primitive, which isn’t part of the main Sodium API. It breaks the property of non-detectability of cell updates/steps. The rule with this primitive is that you should only use it in functions that don’t allow the caller to detect the Cell updates.

pub fn value(&self) -> Stream<A>

Return a Stream that is guaranteed to fire at least once.

When value is called, the returned Stream will fire once in the current transaction with the current value of this Cell and thereafter behaves like Cell::updates.

Important

This is an operational primitive, which isn’t part of the main Sodium API. It breaks the property of non-detectability of cell updates/steps. The rule with this primitive is that you should only use it in functions that don’t allow the caller to detect the Cell updates.

pub fn map<B: Clone + Send + 'static, FN: IsLambda1<A, B> + Send + Sync + 'static>( &self, f: FN, ) -> Cell<B>

Transform the Cells value with the supplied function.

The returned Cell always reflects the value produced by the function applied to the input Cells value. The given function must be referentially transparent.

pub fn lift2<B: Clone + Send + 'static, C: Clone + Send + 'static, FN: IsLambda2<A, B, C> + Send + 'static>( &self, cb: &Cell<B>, f: FN, ) -> Cell<C>

Lift a binary function into cells so the returned Cell always reflects the specified function applied to the input cells’ values.

pub fn lift3<B: Clone + Send + 'static, C: Clone + Send + 'static, D: Clone + Send + 'static, FN: IsLambda3<A, B, C, D> + Send + 'static>( &self, cb: &Cell<B>, cc: &Cell<C>, f: FN, ) -> Cell<D>

Lift a ternary function into cells so the returned Cell always reflects the specified function applied to the input cells’ values.

pub fn lift4<B: Clone + Send + 'static, C: Clone + Send + 'static, D: Clone + Send + 'static, E: Clone + Send + 'static, FN: IsLambda4<A, B, C, D, E> + Send + 'static>( &self, cb: &Cell<B>, cc: &Cell<C>, cd: &Cell<D>, f: FN, ) -> Cell<E>

Lift a quaternary function into cells so the returned Cell always reflects the specified function applied to the input cells’ values.

pub fn lift5<B: Clone + Send + 'static, C: Clone + Send + 'static, D: Clone + Send + 'static, E: Clone + Send + 'static, F: Clone + Send + 'static, FN: IsLambda5<A, B, C, D, E, F> + Send + 'static>( &self, cb: &Cell<B>, cc: &Cell<C>, cd: &Cell<D>, ce: &Cell<E>, f: FN, ) -> Cell<F>

Lift a five-argument function into cells so the returned Cell always reflects the specified function applied to the input cells’ values.

pub fn lift6<B: Clone + Send + 'static, C: Clone + Send + 'static, D: Clone + Send + 'static, E: Clone + Send + 'static, F: Clone + Send + 'static, G: Clone + Send + 'static, FN: IsLambda6<A, B, C, D, E, F, G> + Send + 'static>( &self, cb: &Cell<B>, cc: &Cell<C>, cd: &Cell<D>, ce: &Cell<E>, cf: &Cell<F>, f: FN, ) -> Cell<G>

Lift a six argument function into cells so the returned Cell always reflects the specified function applied to the input cells’ values.

pub fn switch_s(csa: &Cell<Stream<A>>) -> Stream<A>

Unwrap a Stream in a Cell to give a time-varying stream implementation.

pub fn switch_c(cca: &Cell<Cell<A>>) -> Cell<A>

Unwrap a Cell in another Cell to give a time-varying cell implementation.

pub fn listen_weak<K: FnMut(&A) + Send + Sync + 'static>( &self, k: K, ) -> Listener

A variant of listen that will deregister the listener automatically if the listener is garbage-collected.

pub fn listen<K: IsLambda1<A, ()> + Send + Sync + 'static>( &self, k: K, ) -> Listener

Listen for updates to the value of this Cell.

This is the observer pattern. The returned Listener has an unlisten method to cause the listener to be removed.

This is an operational mechanism for interfacing between the world of I/O and FRP.

Trait Implementations

impl<A> Clone for Cell<A>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.