A helper macro to create closures which will clone its environment.
Add the following line to your Cargo.toml file:
toml
clonesure = "0.3.0"
When define parameters of a closure, use @var to clone a variable, use @mut var to clone a mutable variable.
Cloned variables must be in front of closure parameters.
E.g.:
rust
cc!(|@a, @mut b, c| a + b + c)
will be translated to:
rust
{
let a = a.clone();
let mut b = b.clone();
move |c| a + b + c
}
```rust use clonesure::cc;
fn main() {
// cc will implicitly move its environment
let s1 = String::from("111");
let s2 = String::from("222");
asserteq!(
// implicitly move s1 into the closure
// brackets of the closure's body are optional
cc!(|| s1)(),
"111"
);
asserteq!(
// explicitly move s2 into the closure
cc!(move || s2)(),
"222"
);
// clone one var let s1 = String::from("111"); asserteq!( // clone s1 into the closure cc!(|@s1| s1)(), "111" ); asserteq!( s1, // the original s1 is still alive "111", );
// clone many vars let s1 = String::from("111"); let s2 = String::from("222"); assert_eq!(cc!(|@s1, @s2| s1 + &s2)(), "111222");
// clone var mut let s1 = String::from("111"); let s2 = String::from("222"); assert_eq!( cc!(|@mut s1, @s2| { s1 = s1 + &s2; s1 })(), "111222" );
// with closure params // cloned vars must be in front of closure params let s1 = String::from("111"); let s2 = String::from("222"); let s3 = String::from("333"); assert_eq!( cc!(|@mut s1, @s2, s3| { s1 = s1 + &s2 + s3; s1 })(&s3), "111222333" );
// param type, param pattern, return type let s1 = String::from("111"); let s2 = String::from("222"); let s3 = String::from("333"); let s4 = 444; assert_eq!( cc!(|@mut s1, @s2, s3: String, &s4| -> String { s1 = s1 + &s2 + &s3; format!("{}{}", s1, s4) })(s3, &s4), "111222333444" ); } ```