40 lines
819 B
Rust
40 lines
819 B
Rust
// Go's defer in Rust, with a little twist!
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struct Defer<F: Fn()> {
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f: F,
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}
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impl<F: Fn()> Drop for Defer<F> {
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fn drop(&mut self) {
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(self.f)()
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}
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}
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// Only added this for Go-syntax familiarity ;-)
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fn defer<F: Fn()>(f: F) -> Defer<F> {
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Defer { f }
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}
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// Changed your mind about the defer?
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// (Note: This leaks the closure! Don't actually do this!)
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fn undefer<F: Fn()>(token: Defer<F>) {
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use std::mem;
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mem::forget(token);
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}
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fn main() {
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let mut i = 1;
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// Calling it "token" ... could be something else. The lifetime of this
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// controls when the action is run.
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let token = defer(move || println!("Value is: {}", i));
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i += 1;
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println!("Value is: {}", i);
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// Oh, now I changed my mind about the previous defer:
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undefer(token);
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}
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// Prints:
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// Value is: 2
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