46 lines
1.4 KiB
Rust
46 lines
1.4 KiB
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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#![unstable(feature = "collections_range", reason = "was just added")]
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//! Range syntax.
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use core::option::Option::{self, None, Some};
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use core::ops::{RangeFull, Range, RangeTo, RangeFrom};
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/// **RangeArgument** is implemented by Rust's built-in range types, produced
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/// by range syntax like `..`, `a..`, `..b` or `c..d`.
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pub trait RangeArgument<T> {
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/// Start index (inclusive)
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///
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/// Return start value if present, else `None`.
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fn start(&self) -> Option<&T> { None }
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/// End index (exclusive)
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///
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/// Return end value if present, else `None`.
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fn end(&self) -> Option<&T> { None }
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}
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impl<T> RangeArgument<T> for RangeFull {}
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impl<T> RangeArgument<T> for RangeFrom<T> {
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fn start(&self) -> Option<&T> { Some(&self.start) }
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}
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impl<T> RangeArgument<T> for RangeTo<T> {
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fn end(&self) -> Option<&T> { Some(&self.end) }
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}
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impl<T> RangeArgument<T> for Range<T> {
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fn start(&self) -> Option<&T> { Some(&self.start) }
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fn end(&self) -> Option<&T> { Some(&self.end) }
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}
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