443 lines
12 KiB
Rust
443 lines
12 KiB
Rust
// Copyright 2013 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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//! Operations on boolean values (`bool` type)
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//!
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//! A quick summary:
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//!
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//! ## Trait implementations for `bool`
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//!
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//! Implementations of the following traits:
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//!
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//! * `FromStr`
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//! * `ToStr`
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//! * `Not`
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//! * `Ord`
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//! * `TotalOrd`
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//! * `Eq`
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//! * `Default`
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//! * `Zero`
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//!
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//! ## Various functions to compare `bool`s
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//!
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//! All of the standard comparison functions one would expect: `and`, `eq`, `or`,
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//! and more.
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//!
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//! Also, a few conversion functions: `to_bit` and `to_str`.
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use option::{None, Option, Some};
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use from_str::FromStr;
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use to_str::ToStr;
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use num::FromPrimitive;
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#[cfg(not(test))] use cmp::{Eq, Ord, TotalOrd, Ordering};
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#[cfg(not(test))] use ops::{Not, BitAnd, BitOr, BitXor};
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#[cfg(not(test))] use default::Default;
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#[cfg(not(test))] use num::Zero;
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/////////////////////////////////////////////////////////////////////////////
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// Freestanding functions
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/////////////////////////////////////////////////////////////////////////////
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/// Iterates over all truth values, passing them to the given block.
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///
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/// There are no guarantees about the order values will be given.
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///
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/// # Examples
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///
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/// ```
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/// std::bool::all_values(|x: bool| {
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/// println(x.to_str());
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/// })
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/// ```
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#[inline]
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pub fn all_values(blk: |v: bool|) {
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blk(true);
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blk(false);
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}
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/////////////////////////////////////////////////////////////////////////////
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// Methods on `bool`
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/////////////////////////////////////////////////////////////////////////////
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/// Extension methods on a `bool`
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pub trait Bool {
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/// Conjunction of two boolean values.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(true.and(true), true);
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/// assert_eq!(true.and(false), false);
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/// assert_eq!(false.and(true), false);
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/// assert_eq!(false.and(false), false);
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/// ```
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fn and(self, b: bool) -> bool;
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/// Disjunction of two boolean values.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(true.or(true), true);
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/// assert_eq!(true.or(false), true);
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/// assert_eq!(false.or(true), true);
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/// assert_eq!(false.or(false), false);
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/// ```
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fn or(self, b: bool) -> bool;
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/// An 'exclusive or' of two boolean values.
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///
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/// 'exclusive or' is identical to `or(and(a, not(b)), and(not(a), b))`.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(true.xor(true), false);
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/// assert_eq!(true.xor(false), true);
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/// assert_eq!(false.xor(true), true);
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/// assert_eq!(false.xor(false), false);
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/// ```
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fn xor(self, b: bool) -> bool;
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/// Implication between two boolean values.
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///
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/// Implication is often phrased as 'if a then b.'
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///
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/// 'if a then b' is equivalent to `!a || b`.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(true.implies(true), true);
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/// assert_eq!(true.implies(false), false);
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/// assert_eq!(false.implies(true), true);
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/// assert_eq!(false.implies(false), true);
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/// ```
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fn implies(self, b: bool) -> bool;
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/// Convert a `bool` to a `u8`.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(true.to_bit::<u8>(), 1u8);
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/// assert_eq!(false.to_bit::<u8>(), 0u8);
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/// ```
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fn to_bit<N: FromPrimitive>(self) -> N;
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}
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impl Bool for bool {
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#[inline]
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fn and(self, b: bool) -> bool { self && b }
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#[inline]
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fn or(self, b: bool) -> bool { self || b }
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#[inline]
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fn xor(self, b: bool) -> bool { self ^ b }
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#[inline]
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fn implies(self, b: bool) -> bool { !self || b }
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#[inline]
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fn to_bit<N: FromPrimitive>(self) -> N {
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if self { FromPrimitive::from_u8(1).unwrap() }
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else { FromPrimitive::from_u8(0).unwrap() }
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}
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}
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/////////////////////////////////////////////////////////////////////////////
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// Trait impls on `bool`
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/////////////////////////////////////////////////////////////////////////////
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impl FromStr for bool {
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/// Parse a `bool` from a string.
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///
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/// Yields an `Option<bool>`, because `s` may or may not actually be parseable.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(from_str::<bool>("true"), Some(true));
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/// assert_eq!(from_str::<bool>("false"), Some(false));
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/// assert_eq!(from_str::<bool>("not even a boolean"), None);
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/// ```
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#[inline]
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fn from_str(s: &str) -> Option<bool> {
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match s {
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"true" => Some(true),
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"false" => Some(false),
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_ => None,
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}
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}
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}
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impl ToStr for bool {
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/// Convert a `bool` to a string.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(true.to_str(), ~"true");
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/// assert_eq!(false.to_str(), ~"false");
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/// ```
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#[inline]
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fn to_str(&self) -> ~str {
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if *self { ~"true" } else { ~"false" }
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}
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}
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#[cfg(not(test))]
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impl Not<bool> for bool {
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/// The logical complement of a boolean value.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(!true, false);
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/// assert_eq!(!false, true);
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/// ```
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#[inline]
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fn not(&self) -> bool { !*self }
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}
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#[cfg(not(test))]
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impl BitAnd<bool, bool> for bool {
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/// Conjunction of two boolean values.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(false.bitand(&false), false);
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/// assert_eq!(true.bitand(&false), false);
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/// assert_eq!(false.bitand(&true), false);
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/// assert_eq!(true.bitand(&true), true);
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///
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/// assert_eq!(false & false, false);
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/// assert_eq!(true & false, false);
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/// assert_eq!(false & true, false);
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/// assert_eq!(true & true, true);
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/// ```
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#[inline]
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fn bitand(&self, b: &bool) -> bool { *self & *b }
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}
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#[cfg(not(test))]
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impl BitOr<bool, bool> for bool {
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/// Disjunction of two boolean values.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(false.bitor(&false), false);
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/// assert_eq!(true.bitor(&false), true);
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/// assert_eq!(false.bitor(&true), true);
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/// assert_eq!(true.bitor(&true), true);
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///
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/// assert_eq!(false | false, false);
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/// assert_eq!(true | false, true);
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/// assert_eq!(false | true, true);
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/// assert_eq!(true | true, true);
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/// ```
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#[inline]
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fn bitor(&self, b: &bool) -> bool { *self | *b }
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}
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#[cfg(not(test))]
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impl BitXor<bool, bool> for bool {
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/// An 'exclusive or' of two boolean values.
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///
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/// 'exclusive or' is identical to `or(and(a, not(b)), and(not(a), b))`.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(false.bitxor(&false), false);
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/// assert_eq!(true.bitxor(&false), true);
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/// assert_eq!(false.bitxor(&true), true);
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/// assert_eq!(true.bitxor(&true), false);
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///
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/// assert_eq!(false ^ false, false);
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/// assert_eq!(true ^ false, true);
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/// assert_eq!(false ^ true, true);
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/// assert_eq!(true ^ true, false);
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/// ```
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#[inline]
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fn bitxor(&self, b: &bool) -> bool { *self ^ *b }
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}
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#[cfg(not(test))]
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impl Ord for bool {
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#[inline]
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fn lt(&self, other: &bool) -> bool { self.to_bit::<u8>() < other.to_bit() }
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}
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#[cfg(not(test))]
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impl TotalOrd for bool {
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#[inline]
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fn cmp(&self, other: &bool) -> Ordering { self.to_bit::<u8>().cmp(&other.to_bit()) }
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}
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/// Equality between two boolean values.
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///
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/// Two booleans are equal if they have the same value.
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///
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/// # Examples
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///
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/// ```rust
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/// assert_eq!(false.eq(&true), false);
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/// assert_eq!(false == false, true);
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/// assert_eq!(false != true, true);
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/// assert_eq!(false.ne(&false), false);
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/// ```
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#[cfg(not(test))]
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impl Eq for bool {
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#[inline]
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fn eq(&self, other: &bool) -> bool { (*self) == (*other) }
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}
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#[cfg(not(test))]
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impl Default for bool {
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fn default() -> bool { false }
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}
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#[cfg(not(test))]
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impl Zero for bool {
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fn zero() -> bool { false }
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fn is_zero(&self) -> bool { *self == false }
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}
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#[cfg(test)]
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mod tests {
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use prelude::*;
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use super::all_values;
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#[test]
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fn test_bool() {
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assert_eq!(false.eq(&true), false);
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assert_eq!(false == false, true);
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assert_eq!(false != true, true);
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assert_eq!(false.ne(&false), false);
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assert_eq!(false.bitand(&false), false);
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assert_eq!(true.bitand(&false), false);
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assert_eq!(false.bitand(&true), false);
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assert_eq!(true.bitand(&true), true);
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assert_eq!(false & false, false);
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assert_eq!(true & false, false);
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assert_eq!(false & true, false);
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assert_eq!(true & true, true);
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assert_eq!(false.bitor(&false), false);
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assert_eq!(true.bitor(&false), true);
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assert_eq!(false.bitor(&true), true);
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assert_eq!(true.bitor(&true), true);
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assert_eq!(false | false, false);
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assert_eq!(true | false, true);
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assert_eq!(false | true, true);
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assert_eq!(true | true, true);
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assert_eq!(false.bitxor(&false), false);
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assert_eq!(true.bitxor(&false), true);
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assert_eq!(false.bitxor(&true), true);
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assert_eq!(true.bitxor(&true), false);
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assert_eq!(false ^ false, false);
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assert_eq!(true ^ false, true);
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assert_eq!(false ^ true, true);
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assert_eq!(true ^ true, false);
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assert_eq!(!true, false);
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assert_eq!(!false, true);
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assert_eq!(true.to_str(), ~"true");
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assert_eq!(false.to_str(), ~"false");
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assert_eq!(from_str::<bool>("true"), Some(true));
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assert_eq!(from_str::<bool>("false"), Some(false));
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assert_eq!(from_str::<bool>("not even a boolean"), None);
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assert_eq!(true.and(true), true);
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assert_eq!(true.and(false), false);
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assert_eq!(false.and(true), false);
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assert_eq!(false.and(false), false);
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assert_eq!(true.or(true), true);
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assert_eq!(true.or(false), true);
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assert_eq!(false.or(true), true);
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assert_eq!(false.or(false), false);
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assert_eq!(true.xor(true), false);
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assert_eq!(true.xor(false), true);
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assert_eq!(false.xor(true), true);
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assert_eq!(false.xor(false), false);
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assert_eq!(true.implies(true), true);
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assert_eq!(true.implies(false), false);
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assert_eq!(false.implies(true), true);
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assert_eq!(false.implies(false), true);
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assert_eq!(true.to_bit::<u8>(), 1u8);
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assert_eq!(false.to_bit::<u8>(), 0u8);
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}
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#[test]
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fn test_bool_from_str() {
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all_values(|v| {
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assert!(Some(v) == FromStr::from_str(v.to_str()))
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});
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}
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#[test]
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fn test_bool_to_str() {
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assert_eq!(false.to_str(), ~"false");
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assert_eq!(true.to_str(), ~"true");
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}
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#[test]
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fn test_bool_to_bit() {
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all_values(|v| {
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assert_eq!(v.to_bit::<u8>(), if v { 1u8 } else { 0u8 });
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assert_eq!(v.to_bit::<uint>(), if v { 1u } else { 0u });
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assert_eq!(v.to_bit::<int>(), if v { 1i } else { 0i });
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});
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}
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#[test]
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fn test_bool_ord() {
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assert!(true > false);
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assert!(!(false > true));
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assert!(false < true);
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assert!(!(true < false));
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assert!(false <= false);
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assert!(false >= false);
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assert!(true <= true);
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assert!(true >= true);
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assert!(false <= true);
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assert!(!(false >= true));
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assert!(true >= false);
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assert!(!(true <= false));
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}
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#[test]
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fn test_bool_totalord() {
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assert_eq!(true.cmp(&true), Equal);
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assert_eq!(false.cmp(&false), Equal);
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assert_eq!(true.cmp(&false), Greater);
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assert_eq!(false.cmp(&true), Less);
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}
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}
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