Repository navigation
Closure-level inline constants #3687
Description
I propose to add closure-level inline constants. For example the following code
let closeure_uuid = Uuid::new_v4();
let lambda = || {
println!("Execution UUID {}",Uuid::new_v4());
println!("Closure UUID {}",closeure_uuid);
};
lambda ();
lambda ();
It could be rewritten as
let lambda = || {
println!("Execution UUID {}",Uuid::new_v4());
println!("Closure UUID {}",cc{Uuid::new_v4())});
};
lambda ();
lambda ();
with a new cc keyword similar to constant. This would have similar advantages as inline_const rust-lang/rust#104087. Use cases:
Finer control on what is getting moved inside the lambda. For example
cc{very_larnge_vector.iter().min()}
or
cc{struct.field.other_filed}
More ergonomic dealing with ref counting. Example:
cc{button.clone()}.enable();
Those expressions should be executed when the closure is created and dropped when the closure is dropped.
Activity
workingjubilee commentedon Sep 24, 2024
I don't understand the proposal tbh, is this just an abbreviated syntax for
const {}?kennytm commentedon Sep 24, 2024
this is like one of the capturing alternatives proposed in #3680 (comment).
as explained in #3680 (comment) it is very hard to grasp the scope/lifetime of the
cc {}'ed expression for newcomers.workingjubilee commentedon Sep 24, 2024
ah, I see. thank you.