Serializable closures.
This library provides macros to wrap closures such that they can serialized and sent between other processes running the same binary.
rust
fn sum_of_squares(input: &[i32]) -> i32 {
input.dist_iter()
.map(Fn!(|&i| i * i))
.sum()
}
For example, if you have multiple forks of a process, or the same binary running on each of a cluster of machines, this library would help you to send closures between them.
This library aims to work in as simple and un-magical a way as possible. It
currently requires nightly Rust for the unboxed_closures and fn_traits
features (rust issue #29625).
Inferred, non-capturing closure:
rust
|a| a+1
rust
FnMut!(|a| a+1)
Annotated, non-capturing closure:
rust
|a: String| -> String { a.to_uppercase() }
rust
FnMut!(|a: String| -> String { a.to_uppercase() })
Inferred closure, capturing num:
rust
let mut num = 0;
|a| num += a
rust
let mut num = 0;
FnMut!([num] |a| *num += a)
Note: As this is a FnMut closure, num is a mutable reference, and must be
dereferenced to use.
move closure, capturing hello and world:
rust
let hello = String::from("hello");
let mut world = String::new();
move |name| {
world += (hello.to_uppercase() + name).as_str();
}
rust
let hello = String::from("hello");
let mut world = String::new();
FnMut!([hello, world] move |name| {
*world += (hello.to_uppercase() + name).as_str();
})
Note: world must be dereferenced to use.
As visible above, there are currently some minor limitations:
* The captured variables in FnMut and Fn closures are references, so need
to be dereferenced;
* Compiler errors are not as helpful as normal:
text
error[E0308]: mismatched types
...
= note: expected type `for<..> fn(&'r mut (..), (..))`
found type `[closure@<FnMut macros>:9:9: 10:44 my_var:_]`
means that my_var is a captured variable, but was not explicitly listed.
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