0d5bcb14ad
Many of the modifications putting in `Box::new` calls also include a pointer to Issue 22405, which tracks going back to `box <expr>` if possible in the future. (Still tried to use `Box<_>` where it sufficed; thus some tests still have `box_syntax` enabled, as they use a mix of `box` and `Box::new`.) Precursor for overloaded-`box` and placement-`in`; see Issue 22181.
35 lines
1.0 KiB
Rust
35 lines
1.0 KiB
Rust
// Copyright 2014 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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// ignore-pretty
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#![allow(unknown_features)]
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#![feature(unboxed_closures)]
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struct Parser<'a, I, O> {
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parse: Box<FnMut(I) -> Result<O, String> + 'a>
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}
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impl<'a, I: 'a, O: 'a> Parser<'a, I, O> {
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fn compose<K: 'a>(mut self, mut rhs: Parser<'a, O, K>) -> Parser<'a, I, K> {
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// FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
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Parser {
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parse: Box::new(move |x: I| {
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match (self.parse)(x) {
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Ok(r) => (rhs.parse)(r),
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Err(e) => Err(e)
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}
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})
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}
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}
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}
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fn main() {}
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