Function scope 

pub fn scope<T>(f: impl FnOnce() -> T) -> (ScopeHandle, T)

Runs f inside a new ownership scope and returns its result along with a handle to the scope.

Effects (and nested scopes) created while f executes are owned by the scope: they stay alive without their handles being held, and they are disposed together when the scope is disposed.

A scope created inside another owner (an effect’s run, or an enclosing scope) is kept alive by that owner — even if every ScopeHandle clone is dropped — and is disposed with it. An unowned scope is disposed when the last clone of its handle is dropped; call leak to keep it alive for the remainder of the program.

Examples

use std::cell::RefCell;
use std::rc::Rc;

use adaptite::{on_cleanup, scope};

let torn_down = Rc::new(RefCell::new(false));

let (handle, greeting) = scope({
    let torn_down = Rc::clone(&torn_down);
    move || {
        // Effects created here would be owned by the scope and disposed with it.
        on_cleanup(move || *torn_down.borrow_mut() = true);
        "hello"
    }
});

assert_eq!(greeting, "hello");
assert!(!handle.is_disposed());

handle.dispose();
assert!(*torn_down.borrow());