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45 lines
685 B
Markdown
45 lines
685 B
Markdown
---
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date: 2020-09-23
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id: 8353cf5c-2d2d-480a-b957-0e90da847e1c
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title: Rust Closures
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---
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# Syntax
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## Long
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``` rust
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fn main() {
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let double_closure = |num: u32| -> u32 { 2 * num };
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println!("2 times 3 = {}", double_closure(3));
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}
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```
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## Abbreviated
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``` rust
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fn main() {
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let double_closure = |num| 2 * num;
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println!("2 times 3 = {}", double_closure(3));
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}
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```
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# Closure variable scope
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Unlike [Rust functions](20200827170931-functions_macros) Closures can
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capture their environment and access variables from the scope in which
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they're defined:
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``` rust
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fn main() {
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let x = 4;
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let equal_to_x = |z| z == x;
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let y = 4;
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assert!(equal_to_x(y));
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}
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```
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