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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![unstable(feature = "collections_range", reason = "was just added")]
//! Range syntax.
use core::option::Option::{self, None, Some};
use core::ops::{RangeFull, Range, RangeTo, RangeFrom};
/// **RangeArgument** is implemented by Rust's built-in range types, produced
/// by range syntax like `..`, `a..`, `..b` or `c..d`.
pub trait RangeArgument<T> {
/// Start index (inclusive)
///
/// Return start value if present, else `None`.
fn start(&self) -> Option<&T> { None }
/// End index (exclusive)
///
/// Return end value if present, else `None`.
fn end(&self) -> Option<&T> { None }
}
impl<T> RangeArgument<T> for RangeFull {}
impl<T> RangeArgument<T> for RangeFrom<T> {
fn start(&self) -> Option<&T> { Some(&self.start) }
}
impl<T> RangeArgument<T> for RangeTo<T> {
fn end(&self) -> Option<&T> { Some(&self.end) }
}
impl<T> RangeArgument<T> for Range<T> {
fn start(&self) -> Option<&T> { Some(&self.start) }
fn end(&self) -> Option<&T> { Some(&self.end) }
}
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