Struct ClosureSubscription 

pub struct ClosureSubscription<F>(pub F);

A functional adapter that turns a closure into a Subscription.

This struct allows users to define teardown/unsubscription logic using a simple closure, without needing to define a custom struct that implements the Subscription trait. It is particularly useful when working with the create operator, where you often need to return a cleanup action.

Why is this needed?

Rust’s orphan rules and type inference limitations prevent us from directly implementing Subscription for all FnOnce() closures globally. ClosureSubscription serves as an explicit wrapper to tell the compiler: “Treat this closure as a Subscription”.

Zero-Cost Abstraction

This is a newtype wrapper that compiles down to a direct function call. There is no runtime overhead compared to calling the closure directly.

Example

use std::convert::Infallible;

use rxrust::{prelude::*, subscription::ClosureSubscription};

Local::create::<(), Infallible, _, _>(|_emitter| {
  println!("Subscribed");

  // Return a closure wrapped in ClosureSubscription as the teardown logic
  ClosureSubscription(move || {
    println!("Unsubscribed - cleaning up resources");
  })
});

Tuple Fields

0: F

Trait Implementations

impl<F> Subscription for ClosureSubscription<F>

where F: FnOnce(),

fn unsubscribe(self)

Cancel the subscription (terminal operation, consumes self)

fn is_closed(&self) -> bool

Check if the subscription is closed (completed or unsubscribed)

fn unsubscribe_when_dropped(self) -> SubscriptionGuard<Self>

where Self: Sized,

Activates “RAII” behavior for this subscription. That means unsubscribe() will be called automatically as soon as the returned value goes out of scope.