| // 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 = "waiting for dust to settle on inclusive ranges", |
| issue = "30877")] |
| |
| //! 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) |
| } |
| } |