28 lines
783 B
Rust
28 lines
783 B
Rust
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![feature(unboxed_closures)]
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#![feature(core)]
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struct Fun<F>(F);
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impl<F, T> FnOnce<(T,)> for Fun<F> where F: Fn(T) -> T {
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type Output = T;
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extern "rust-call" fn call_once(self, (t,): (T,)) -> T {
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(self.0)(t)
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}
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}
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fn main() {
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let fun = Fun(|i: isize| i * 2);
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println!("{}", fun(3));
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}
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