core: Inherit the iter module

1 files changed, 0 insertions, 3090 deletions

diff --git a/src/libstd/iter.rs b/src/libstd/iter.rs
deleted file mode 100644
index 7dc1252fc77..00000000000
--- a/src/libstd/iter.rs
+++ /dev/null
@@ -1,3090 +0,0 @@
-// Copyright 2013-2014 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.
-
-/*!
-
-Composable external iterators
-
-# The `Iterator` trait
-
-This module defines Rust's core iteration trait. The `Iterator` trait has one
-unimplemented method, `next`. All other methods are derived through default
-methods to perform operations such as `zip`, `chain`, `enumerate`, and `fold`.
-
-The goal of this module is to unify iteration across all containers in Rust.
-An iterator can be considered as a state machine which is used to track which
-element will be yielded next.
-
-There are various extensions also defined in this module to assist with various
-types of iteration, such as the `DoubleEndedIterator` for iterating in reverse,
-the `FromIterator` trait for creating a container from an iterator, and much
-more.
-
-## Rust's `for` loop
-
-The special syntax used by rust's `for` loop is based around the `Iterator`
-trait defined in this module. For loops can be viewed as a syntactical expansion
-into a `loop`, for example, the `for` loop in this example is essentially
-translated to the `loop` below.
-
-```rust
-let values = ~[1, 2, 3];
-
-// "Syntactical sugar" taking advantage of an iterator
-for &x in values.iter() {
-    println!("{}", x);
-}
-
-// Rough translation of the iteration without a `for` iterator.
-let mut it = values.iter();
-loop {
-    match it.next() {
-        Some(&x) => {
-            println!("{}", x);
-        }
-        None => { break }
-    }
-}
-```
-
-This `for` loop syntax can be applied to any iterator over any type.
-
-## Iteration protocol and more
-
-More detailed information about iterators can be found in the [container
-guide](http://static.rust-lang.org/doc/master/guide-container.html) with
-the rest of the rust manuals.
-
-*/
-
-use cmp;
-use num::{Zero, One, CheckedAdd, CheckedSub, Saturating, ToPrimitive, Int};
-use option::{Option, Some, None};
-use ops::{Add, Mul, Sub};
-use cmp::{Eq, Ord, TotalOrd};
-use clone::Clone;
-use uint;
-use mem;
-
-/// Conversion from an `Iterator`
-pub trait FromIterator<A> {
-    /// Build a container with elements from an external iterator.
-    fn from_iter<T: Iterator<A>>(iterator: T) -> Self;
-}
-
-/// A type growable from an `Iterator` implementation
-pub trait Extendable<A>: FromIterator<A> {
-    /// Extend a container with the elements yielded by an iterator
-    fn extend<T: Iterator<A>>(&mut self, iterator: T);
-}
-
-/// An interface for dealing with "external iterators". These types of iterators
-/// can be resumed at any time as all state is stored internally as opposed to
-/// being located on the call stack.
-///
-/// The Iterator protocol states that an iterator yields a (potentially-empty,
-/// potentially-infinite) sequence of values, and returns `None` to signal that
-/// it's finished. The Iterator protocol does not define behavior after `None`
-/// is returned. A concrete Iterator implementation may choose to behave however
-/// it wishes, either by returning `None` infinitely, or by doing something
-/// else.
-pub trait Iterator<A> {
-    /// Advance the iterator and return the next value. Return `None` when the end is reached.
-    fn next(&mut self) -> Option<A>;
-
-    /// Return a lower bound and upper bound on the remaining length of the iterator.
-    ///
-    /// The common use case for the estimate is pre-allocating space to store the results.
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) { (0, None) }
-
-    /// Chain this iterator with another, returning a new iterator which will
-    /// finish iterating over the current iterator, and then it will iterate
-    /// over the other specified iterator.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [0];
-    /// let b = [1];
-    /// let mut it = a.iter().chain(b.iter());
-    /// assert_eq!(it.next().unwrap(), &0);
-    /// assert_eq!(it.next().unwrap(), &1);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn chain<U: Iterator<A>>(self, other: U) -> Chain<Self, U> {
-        Chain{a: self, b: other, flag: false}
-    }
-
-    /// Creates an iterator which iterates over both this and the specified
-    /// iterators simultaneously, yielding the two elements as pairs. When
-    /// either iterator returns None, all further invocations of next() will
-    /// return None.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [0];
-    /// let b = [1];
-    /// let mut it = a.iter().zip(b.iter());
-    /// assert_eq!(it.next().unwrap(), (&0, &1));
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn zip<B, U: Iterator<B>>(self, other: U) -> Zip<Self, U> {
-        Zip{a: self, b: other}
-    }
-
-    /// Creates a new iterator which will apply the specified function to each
-    /// element returned by the first, yielding the mapped element instead.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2];
-    /// let mut it = a.iter().map(|&x| 2 * x);
-    /// assert_eq!(it.next().unwrap(), 2);
-    /// assert_eq!(it.next().unwrap(), 4);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn map<'r, B>(self, f: |A|: 'r -> B) -> Map<'r, A, B, Self> {
-        Map{iter: self, f: f}
-    }
-
-    /// Creates an iterator which applies the predicate to each element returned
-    /// by this iterator. Only elements which have the predicate evaluate to
-    /// `true` will be yielded.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2];
-    /// let mut it = a.iter().filter(|&x| *x > 1);
-    /// assert_eq!(it.next().unwrap(), &2);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn filter<'r>(self, predicate: |&A|: 'r -> bool) -> Filter<'r, A, Self> {
-        Filter{iter: self, predicate: predicate}
-    }
-
-    /// Creates an iterator which both filters and maps elements.
-    /// If the specified function returns None, the element is skipped.
-    /// Otherwise the option is unwrapped and the new value is yielded.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2];
-    /// let mut it = a.iter().filter_map(|&x| if x > 1 {Some(2 * x)} else {None});
-    /// assert_eq!(it.next().unwrap(), 4);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn filter_map<'r, B>(self, f: |A|: 'r -> Option<B>) -> FilterMap<'r, A, B, Self> {
-        FilterMap { iter: self, f: f }
-    }
-
-    /// Creates an iterator which yields a pair of the value returned by this
-    /// iterator plus the current index of iteration.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [100, 200];
-    /// let mut it = a.iter().enumerate();
-    /// assert_eq!(it.next().unwrap(), (0, &100));
-    /// assert_eq!(it.next().unwrap(), (1, &200));
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn enumerate(self) -> Enumerate<Self> {
-        Enumerate{iter: self, count: 0}
-    }
-
-
-    /// Creates an iterator that has a `.peek()` method
-    /// that returns an optional reference to the next element.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let xs = [100, 200, 300];
-    /// let mut it = xs.iter().map(|x| *x).peekable();
-    /// assert_eq!(it.peek().unwrap(), &100);
-    /// assert_eq!(it.next().unwrap(), 100);
-    /// assert_eq!(it.next().unwrap(), 200);
-    /// assert_eq!(it.peek().unwrap(), &300);
-    /// assert_eq!(it.peek().unwrap(), &300);
-    /// assert_eq!(it.next().unwrap(), 300);
-    /// assert!(it.peek().is_none());
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn peekable(self) -> Peekable<A, Self> {
-        Peekable{iter: self, peeked: None}
-    }
-
-    /// Creates an iterator which invokes the predicate on elements until it
-    /// returns false. Once the predicate returns false, all further elements are
-    /// yielded.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 2, 1];
-    /// let mut it = a.iter().skip_while(|&a| *a < 3);
-    /// assert_eq!(it.next().unwrap(), &3);
-    /// assert_eq!(it.next().unwrap(), &2);
-    /// assert_eq!(it.next().unwrap(), &1);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn skip_while<'r>(self, predicate: |&A|: 'r -> bool) -> SkipWhile<'r, A, Self> {
-        SkipWhile{iter: self, flag: false, predicate: predicate}
-    }
-
-    /// Creates an iterator which yields elements so long as the predicate
-    /// returns true. After the predicate returns false for the first time, no
-    /// further elements will be yielded.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 2, 1];
-    /// let mut it = a.iter().take_while(|&a| *a < 3);
-    /// assert_eq!(it.next().unwrap(), &1);
-    /// assert_eq!(it.next().unwrap(), &2);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn take_while<'r>(self, predicate: |&A|: 'r -> bool) -> TakeWhile<'r, A, Self> {
-        TakeWhile{iter: self, flag: false, predicate: predicate}
-    }
-
-    /// Creates an iterator which skips the first `n` elements of this iterator,
-    /// and then it yields all further items.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// let mut it = a.iter().skip(3);
-    /// assert_eq!(it.next().unwrap(), &4);
-    /// assert_eq!(it.next().unwrap(), &5);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn skip(self, n: uint) -> Skip<Self> {
-        Skip{iter: self, n: n}
-    }
-
-    /// Creates an iterator which yields the first `n` elements of this
-    /// iterator, and then it will always return None.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// let mut it = a.iter().take(3);
-    /// assert_eq!(it.next().unwrap(), &1);
-    /// assert_eq!(it.next().unwrap(), &2);
-    /// assert_eq!(it.next().unwrap(), &3);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn take(self, n: uint) -> Take<Self> {
-        Take{iter: self, n: n}
-    }
-
-    /// Creates a new iterator which behaves in a similar fashion to fold.
-    /// There is a state which is passed between each iteration and can be
-    /// mutated as necessary. The yielded values from the closure are yielded
-    /// from the Scan instance when not None.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// let mut it = a.iter().scan(1, |fac, &x| {
-    ///   *fac = *fac * x;
-    ///   Some(*fac)
-    /// });
-    /// assert_eq!(it.next().unwrap(), 1);
-    /// assert_eq!(it.next().unwrap(), 2);
-    /// assert_eq!(it.next().unwrap(), 6);
-    /// assert_eq!(it.next().unwrap(), 24);
-    /// assert_eq!(it.next().unwrap(), 120);
-    /// assert!(it.next().is_none());
-    /// ```
-    #[inline]
-    fn scan<'r, St, B>(self, initial_state: St, f: |&mut St, A|: 'r -> Option<B>)
-        -> Scan<'r, A, B, Self, St> {
-        Scan{iter: self, f: f, state: initial_state}
-    }
-
-    /// Creates an iterator that maps each element to an iterator,
-    /// and yields the elements of the produced iterators
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// use std::iter::count;
-    ///
-    /// let xs = [2u, 3];
-    /// let ys = [0u, 1, 0, 1, 2];
-    /// let mut it = xs.iter().flat_map(|&x| count(0u, 1).take(x));
-    /// // Check that `it` has the same elements as `ys`
-    /// let mut i = 0;
-    /// for x in it {
-    ///     assert_eq!(x, ys[i]);
-    ///     i += 1;
-    /// }
-    /// ```
-    #[inline]
-    fn flat_map<'r, B, U: Iterator<B>>(self, f: |A|: 'r -> U)
-        -> FlatMap<'r, A, Self, U> {
-        FlatMap{iter: self, f: f, frontiter: None, backiter: None }
-    }
-
-    /// Creates an iterator that yields `None` forever after the underlying
-    /// iterator yields `None`. Random-access iterator behavior is not
-    /// affected, only single and double-ended iterator behavior.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// fn process<U: Iterator<int>>(it: U) -> int {
-    ///     let mut it = it.fuse();
-    ///     let mut sum = 0;
-    ///     for x in it {
-    ///         if x > 5 {
-    ///             continue;
-    ///         }
-    ///         sum += x;
-    ///     }
-    ///     // did we exhaust the iterator?
-    ///     if it.next().is_none() {
-    ///         sum += 1000;
-    ///     }
-    ///     sum
-    /// }
-    /// let x = ~[1,2,3,7,8,9];
-    /// assert_eq!(process(x.move_iter()), 1006);
-    /// ```
-    #[inline]
-    fn fuse(self) -> Fuse<Self> {
-        Fuse{iter: self, done: false}
-    }
-
-    /// Creates an iterator that calls a function with a reference to each
-    /// element before yielding it. This is often useful for debugging an
-    /// iterator pipeline.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// use std::iter::AdditiveIterator;
-    ///
-    /// let xs = [1u, 4, 2, 3, 8, 9, 6];
-    /// let sum = xs.iter()
-    ///             .map(|&x| x)
-    ///             .inspect(|&x| println!("filtering {}", x))
-    ///             .filter(|&x| x % 2 == 0)
-    ///             .inspect(|&x| println!("{} made it through", x))
-    ///             .sum();
-    /// println!("{}", sum);
-    /// ```
-    #[inline]
-    fn inspect<'r>(self, f: |&A|: 'r) -> Inspect<'r, A, Self> {
-        Inspect{iter: self, f: f}
-    }
-
-    /// Creates a wrapper around a mutable reference to the iterator.
-    ///
-    /// This is useful to allow applying iterator adaptors while still
-    /// retaining ownership of the original iterator value.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let mut xs = range(0, 10);
-    /// // sum the first five values
-    /// let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
-    /// assert!(partial_sum == 10);
-    /// // xs.next() is now `5`
-    /// assert!(xs.next() == Some(5));
-    /// ```
-    fn by_ref<'r>(&'r mut self) -> ByRef<'r, Self> {
-        ByRef{iter: self}
-    }
-
-    /// Apply a function to each element, or stop iterating if the
-    /// function returns `false`.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// range(0, 5).advance(|x| {print!("{} ", x); true});
-    /// ```
-    #[inline]
-    fn advance(&mut self, f: |A| -> bool) -> bool {
-        loop {
-            match self.next() {
-                Some(x) => {
-                    if !f(x) { return false; }
-                }
-                None => { return true; }
-            }
-        }
-    }
-
-    /// Loops through the entire iterator, collecting all of the elements into
-    /// a container implementing `FromIterator`.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// let b: ~[int] = a.iter().map(|&x| x).collect();
-    /// assert!(a == b);
-    /// ```
-    #[inline]
-    fn collect<B: FromIterator<A>>(&mut self) -> B {
-        FromIterator::from_iter(self.by_ref())
-    }
-
-    /// Loops through `n` iterations, returning the `n`th element of the
-    /// iterator.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// let mut it = a.iter();
-    /// assert!(it.nth(2).unwrap() == &3);
-    /// assert!(it.nth(2) == None);
-    /// ```
-    #[inline]
-    fn nth(&mut self, mut n: uint) -> Option<A> {
-        loop {
-            match self.next() {
-                Some(x) => if n == 0 { return Some(x) },
-                None => return None
-            }
-            n -= 1;
-        }
-    }
-
-    /// Loops through the entire iterator, returning the last element of the
-    /// iterator.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// assert!(a.iter().last().unwrap() == &5);
-    /// ```
-    #[inline]
-    fn last(&mut self) -> Option<A> {
-        let mut last = None;
-        for x in *self { last = Some(x); }
-        last
-    }
-
-    /// Performs a fold operation over the entire iterator, returning the
-    /// eventual state at the end of the iteration.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// assert!(a.iter().fold(0, |a, &b| a + b) == 15);
-    /// ```
-    #[inline]
-    fn fold<B>(&mut self, init: B, f: |B, A| -> B) -> B {
-        let mut accum = init;
-        loop {
-            match self.next() {
-                Some(x) => { accum = f(accum, x); }
-                None    => { break; }
-            }
-        }
-        accum
-    }
-
-    /// Counts the number of elements in this iterator.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// let mut it = a.iter();
-    /// assert!(it.len() == 5);
-    /// assert!(it.len() == 0);
-    /// ```
-    #[inline]
-    fn len(&mut self) -> uint {
-        self.fold(0, |cnt, _x| cnt + 1)
-    }
-
-    /// Tests whether the predicate holds true for all elements in the iterator.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// assert!(a.iter().all(|x| *x > 0));
-    /// assert!(!a.iter().all(|x| *x > 2));
-    /// ```
-    #[inline]
-    fn all(&mut self, f: |A| -> bool) -> bool {
-        for x in *self { if !f(x) { return false; } }
-        true
-    }
-
-    /// Tests whether any element of an iterator satisfies the specified
-    /// predicate.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// let mut it = a.iter();
-    /// assert!(it.any(|x| *x == 3));
-    /// assert!(!it.any(|x| *x == 3));
-    /// ```
-    #[inline]
-    fn any(&mut self, f: |A| -> bool) -> bool {
-        for x in *self { if f(x) { return true; } }
-        false
-    }
-
-    /// Return the first element satisfying the specified predicate
-    #[inline]
-    fn find(&mut self, predicate: |&A| -> bool) -> Option<A> {
-        for x in *self {
-            if predicate(&x) { return Some(x) }
-        }
-        None
-    }
-
-    /// Return the index of the first element satisfying the specified predicate
-    #[inline]
-    fn position(&mut self, predicate: |A| -> bool) -> Option<uint> {
-        let mut i = 0;
-        for x in *self {
-            if predicate(x) {
-                return Some(i);
-            }
-            i += 1;
-        }
-        None
-    }
-
-    /// Count the number of elements satisfying the specified predicate
-    #[inline]
-    fn count(&mut self, predicate: |A| -> bool) -> uint {
-        let mut i = 0;
-        for x in *self {
-            if predicate(x) { i += 1 }
-        }
-        i
-    }
-
-    /// Return the element that gives the maximum value from the
-    /// specified function.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let xs = [-3i, 0, 1, 5, -10];
-    /// assert_eq!(*xs.iter().max_by(|x| x.abs()).unwrap(), -10);
-    /// ```
-    #[inline]
-    fn max_by<B: TotalOrd>(&mut self, f: |&A| -> B) -> Option<A> {
-        self.fold(None, |max: Option<(A, B)>, x| {
-            let x_val = f(&x);
-            match max {
-                None             => Some((x, x_val)),
-                Some((y, y_val)) => if x_val > y_val {
-                    Some((x, x_val))
-                } else {
-                    Some((y, y_val))
-                }
-            }
-        }).map(|(x, _)| x)
-    }
-
-    /// Return the element that gives the minimum value from the
-    /// specified function.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let xs = [-3i, 0, 1, 5, -10];
-    /// assert_eq!(*xs.iter().min_by(|x| x.abs()).unwrap(), 0);
-    /// ```
-    #[inline]
-    fn min_by<B: TotalOrd>(&mut self, f: |&A| -> B) -> Option<A> {
-        self.fold(None, |min: Option<(A, B)>, x| {
-            let x_val = f(&x);
-            match min {
-                None             => Some((x, x_val)),
-                Some((y, y_val)) => if x_val < y_val {
-                    Some((x, x_val))
-                } else {
-                    Some((y, y_val))
-                }
-            }
-        }).map(|(x, _)| x)
-    }
-}
-
-/// A range iterator able to yield elements from both ends
-pub trait DoubleEndedIterator<A>: Iterator<A> {
-    /// Yield an element from the end of the range, returning `None` if the range is empty.
-    fn next_back(&mut self) -> Option<A>;
-
-    /// Change the direction of the iterator
-    ///
-    /// The flipped iterator swaps the ends on an iterator that can already
-    /// be iterated from the front and from the back.
-    ///
-    ///
-    /// If the iterator also implements RandomAccessIterator, the flipped
-    /// iterator is also random access, with the indices starting at the back
-    /// of the original iterator.
-    ///
-    /// Note: Random access with flipped indices still only applies to the first
-    /// `uint::MAX` elements of the original iterator.
-    #[inline]
-    fn rev(self) -> Rev<Self> {
-        Rev{iter: self}
-    }
-}
-
-/// A double-ended iterator yielding mutable references
-pub trait MutableDoubleEndedIterator {
-    // FIXME: #5898: should be called `reverse`
-    /// Use an iterator to reverse a container in-place
-    fn reverse_(&mut self);
-}
-
-impl<'a, A, T: DoubleEndedIterator<&'a mut A>> MutableDoubleEndedIterator for T {
-    // FIXME: #5898: should be called `reverse`
-    /// Use an iterator to reverse a container in-place
-    fn reverse_(&mut self) {
-        loop {
-            match (self.next(), self.next_back()) {
-                (Some(x), Some(y)) => mem::swap(x, y),
-                _ => break
-            }
-        }
-    }
-}
-
-
-/// An object implementing random access indexing by `uint`
-///
-/// A `RandomAccessIterator` should be either infinite or a `DoubleEndedIterator`.
-pub trait RandomAccessIterator<A>: Iterator<A> {
-    /// Return the number of indexable elements. At most `std::uint::MAX`
-    /// elements are indexable, even if the iterator represents a longer range.
-    fn indexable(&self) -> uint;
-
-    /// Return an element at an index
-    fn idx(&mut self, index: uint) -> Option<A>;
-}
-
-/// An iterator that knows its exact length
-///
-/// This trait is a helper for iterators like the vector iterator, so that
-/// it can support double-ended enumeration.
-///
-/// `Iterator::size_hint` *must* return the exact size of the iterator.
-/// Note that the size must fit in `uint`.
-pub trait ExactSize<A> : DoubleEndedIterator<A> {
-    /// Return the index of the last element satisfying the specified predicate
-    ///
-    /// If no element matches, None is returned.
-    #[inline]
-    fn rposition(&mut self, predicate: |A| -> bool) -> Option<uint> {
-        let (lower, upper) = self.size_hint();
-        assert!(upper == Some(lower));
-        let mut i = lower;
-        loop {
-            match self.next_back() {
-                None => break,
-                Some(x) => {
-                    i = match i.checked_sub(&1) {
-                        Some(x) => x,
-                        None => fail!("rposition: incorrect ExactSize")
-                    };
-                    if predicate(x) {
-                        return Some(i)
-                    }
-                }
-            }
-        }
-        None
-    }
-}
-
-// All adaptors that preserve the size of the wrapped iterator are fine
-// Adaptors that may overflow in `size_hint` are not, i.e. `Chain`.
-impl<A, T: ExactSize<A>> ExactSize<(uint, A)> for Enumerate<T> {}
-impl<'a, A, T: ExactSize<A>> ExactSize<A> for Inspect<'a, A, T> {}
-impl<A, T: ExactSize<A>> ExactSize<A> for Rev<T> {}
-impl<'a, A, B, T: ExactSize<A>> ExactSize<B> for Map<'a, A, B, T> {}
-impl<A, B, T: ExactSize<A>, U: ExactSize<B>> ExactSize<(A, B)> for Zip<T, U> {}
-
-/// An double-ended iterator with the direction inverted
-#[deriving(Clone)]
-pub struct Rev<T> {
-    iter: T
-}
-
-impl<A, T: DoubleEndedIterator<A>> Iterator<A> for Rev<T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> { self.iter.next_back() }
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
-}
-
-impl<A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for Rev<T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> { self.iter.next() }
-}
-
-impl<A, T: DoubleEndedIterator<A> + RandomAccessIterator<A>> RandomAccessIterator<A>
-    for Rev<T> {
-    #[inline]
-    fn indexable(&self) -> uint { self.iter.indexable() }
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<A> {
-        let amt = self.indexable();
-        self.iter.idx(amt - index - 1)
-    }
-}
-
-/// A mutable reference to an iterator
-pub struct ByRef<'a, T> {
-    iter: &'a mut T
-}
-
-impl<'a, A, T: Iterator<A>> Iterator<A> for ByRef<'a, T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> { self.iter.next() }
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
-}
-
-impl<'a, A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for ByRef<'a, T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> { self.iter.next_back() }
-}
-
-/// A trait for iterators over elements which can be added together
-pub trait AdditiveIterator<A> {
-    /// Iterates over the entire iterator, summing up all the elements
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// use std::iter::AdditiveIterator;
-    ///
-    /// let a = [1, 2, 3, 4, 5];
-    /// let mut it = a.iter().map(|&x| x);
-    /// assert!(it.sum() == 15);
-    /// ```
-    fn sum(&mut self) -> A;
-}
-
-impl<A: Add<A, A> + Zero, T: Iterator<A>> AdditiveIterator<A> for T {
-    #[inline]
-    fn sum(&mut self) -> A {
-        let zero: A = Zero::zero();
-        self.fold(zero, |s, x| s + x)
-    }
-}
-
-/// A trait for iterators over elements whose elements can be multiplied
-/// together.
-pub trait MultiplicativeIterator<A> {
-    /// Iterates over the entire iterator, multiplying all the elements
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// use std::iter::{count, MultiplicativeIterator};
-    ///
-    /// fn factorial(n: uint) -> uint {
-    ///     count(1u, 1).take_while(|&i| i <= n).product()
-    /// }
-    /// assert!(factorial(0) == 1);
-    /// assert!(factorial(1) == 1);
-    /// assert!(factorial(5) == 120);
-    /// ```
-    fn product(&mut self) -> A;
-}
-
-impl<A: Mul<A, A> + One, T: Iterator<A>> MultiplicativeIterator<A> for T {
-    #[inline]
-    fn product(&mut self) -> A {
-        let one: A = One::one();
-        self.fold(one, |p, x| p * x)
-    }
-}
-
-/// A trait for iterators over elements which can be compared to one another.
-/// The type of each element must ascribe to the `Ord` trait.
-pub trait OrdIterator<A> {
-    /// Consumes the entire iterator to return the maximum element.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// assert!(a.iter().max().unwrap() == &5);
-    /// ```
-    fn max(&mut self) -> Option<A>;
-
-    /// Consumes the entire iterator to return the minimum element.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// let a = [1, 2, 3, 4, 5];
-    /// assert!(a.iter().min().unwrap() == &1);
-    /// ```
-    fn min(&mut self) -> Option<A>;
-
-    /// `min_max` finds the minimum and maximum elements in the iterator.
-    ///
-    /// The return type `MinMaxResult` is an enum of three variants:
-    /// - `NoElements` if the iterator is empty.
-    /// - `OneElement(x)` if the iterator has exactly one element.
-    /// - `MinMax(x, y)` is returned otherwise, where `x <= y`. Two values are equal if and only if
-    /// there is more than one element in the iterator and all elements are equal.
-    ///
-    /// On an iterator of length `n`, `min_max` does `1.5 * n` comparisons,
-    /// and so faster than calling `min` and `max separately which does `2 * n` comparisons.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// use std::iter::{NoElements, OneElement, MinMax};
-    ///
-    /// let v: [int, ..0] = [];
-    /// assert_eq!(v.iter().min_max(), NoElements);
-    ///
-    /// let v = [1i];
-    /// assert!(v.iter().min_max() == OneElement(&1));
-    ///
-    /// let v = [1i, 2, 3, 4, 5];
-    /// assert!(v.iter().min_max() == MinMax(&1, &5));
-    ///
-    /// let v = [1i, 2, 3, 4, 5, 6];
-    /// assert!(v.iter().min_max() == MinMax(&1, &6));
-    ///
-    /// let v = [1i, 1, 1, 1];
-    /// assert!(v.iter().min_max() == MinMax(&1, &1));
-    /// ```
-    fn min_max(&mut self) -> MinMaxResult<A>;
-}
-
-impl<A: TotalOrd, T: Iterator<A>> OrdIterator<A> for T {
-    #[inline]
-    fn max(&mut self) -> Option<A> {
-        self.fold(None, |max, x| {
-            match max {
-                None    => Some(x),
-                Some(y) => Some(cmp::max(x, y))
-            }
-        })
-    }
-
-    #[inline]
-    fn min(&mut self) -> Option<A> {
-        self.fold(None, |min, x| {
-            match min {
-                None    => Some(x),
-                Some(y) => Some(cmp::min(x, y))
-            }
-        })
-    }
-
-    fn min_max(&mut self) -> MinMaxResult<A> {
-        let (mut min, mut max) = match self.next() {
-            None => return NoElements,
-            Some(x) => {
-                match self.next() {
-                    None => return OneElement(x),
-                    Some(y) => if x < y {(x, y)} else {(y,x)}
-                }
-            }
-        };
-
-        loop {
-            // `first` and `second` are the two next elements we want to look at.
-            // We first compare `first` and `second` (#1). The smaller one is then compared to
-            // current minimum (#2). The larger one is compared to current maximum (#3). This
-            // way we do 3 comparisons for 2 elements.
-            let first = match self.next() {
-                None => break,
-                Some(x) => x
-            };
-            let second = match self.next() {
-                None => {
-                    if first < min {
-                        min = first;
-                    } else if first > max {
-                        max = first;
-                    }
-                    break;
-                }
-                Some(x) => x
-            };
-            if first < second {
-                if first < min {min = first;}
-                if max < second {max = second;}
-            } else {
-                if second < min {min = second;}
-                if max < first {max = first;}
-            }
-        }
-
-        MinMax(min, max)
-    }
-}
-
-/// `MinMaxResult` is an enum returned by `min_max`. See `OrdIterator::min_max` for more detail.
-#[deriving(Clone, Eq, Show)]
-pub enum MinMaxResult<T> {
-    /// Empty iterator
-    NoElements,
-
-    /// Iterator with one element, so the minimum and maximum are the same
-    OneElement(T),
-
-    /// More than one element in the iterator, the first element is not larger than the second
-    MinMax(T, T)
-}
-
-impl<T: Clone> MinMaxResult<T> {
-    /// `into_option` creates an `Option` of type `(T,T)`. The returned `Option` has variant
-    /// `None` if and only if the `MinMaxResult` has variant `NoElements`. Otherwise variant
-    /// `Some(x,y)` is returned where `x <= y`. If `MinMaxResult` has variant `OneElement(x)`,
-    /// performing this operation will make one clone of `x`.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// use std::iter::{NoElements, OneElement, MinMax, MinMaxResult};
-    ///
-    /// let r: MinMaxResult<int> = NoElements;
-    /// assert_eq!(r.into_option(), None)
-    ///
-    /// let r = OneElement(1);
-    /// assert_eq!(r.into_option(), Some((1,1)));
-    ///
-    /// let r = MinMax(1,2);
-    /// assert_eq!(r.into_option(), Some((1,2)));
-    /// ```
-    pub fn into_option(self) -> Option<(T,T)> {
-        match self {
-            NoElements => None,
-            OneElement(x) => Some((x.clone(), x)),
-            MinMax(x, y) => Some((x, y))
-        }
-    }
-}
-
-/// A trait for iterators that are cloneable.
-pub trait CloneableIterator {
-    /// Repeats an iterator endlessly
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// use std::iter::{CloneableIterator, count};
-    ///
-    /// let a = count(1,1).take(1);
-    /// let mut cy = a.cycle();
-    /// assert_eq!(cy.next(), Some(1));
-    /// assert_eq!(cy.next(), Some(1));
-    /// ```
-    fn cycle(self) -> Cycle<Self>;
-}
-
-impl<A, T: Clone + Iterator<A>> CloneableIterator for T {
-    #[inline]
-    fn cycle(self) -> Cycle<T> {
-        Cycle{orig: self.clone(), iter: self}
-    }
-}
-
-/// An iterator that repeats endlessly
-#[deriving(Clone)]
-pub struct Cycle<T> {
-    orig: T,
-    iter: T,
-}
-
-impl<A, T: Clone + Iterator<A>> Iterator<A> for Cycle<T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        match self.iter.next() {
-            None => { self.iter = self.orig.clone(); self.iter.next() }
-            y => y
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        // the cycle iterator is either empty or infinite
-        match self.orig.size_hint() {
-            sz @ (0, Some(0)) => sz,
-            (0, _) => (0, None),
-            _ => (uint::MAX, None)
-        }
-    }
-}
-
-impl<A, T: Clone + RandomAccessIterator<A>> RandomAccessIterator<A> for Cycle<T> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        if self.orig.indexable() > 0 {
-            uint::MAX
-        } else {
-            0
-        }
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<A> {
-        let liter = self.iter.indexable();
-        let lorig = self.orig.indexable();
-        if lorig == 0 {
-            None
-        } else if index < liter {
-            self.iter.idx(index)
-        } else {
-            self.orig.idx((index - liter) % lorig)
-        }
-    }
-}
-
-/// An iterator which strings two iterators together
-#[deriving(Clone)]
-pub struct Chain<T, U> {
-    a: T,
-    b: U,
-    flag: bool
-}
-
-impl<A, T: Iterator<A>, U: Iterator<A>> Iterator<A> for Chain<T, U> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if self.flag {
-            self.b.next()
-        } else {
-            match self.a.next() {
-                Some(x) => return Some(x),
-                _ => ()
-            }
-            self.flag = true;
-            self.b.next()
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (a_lower, a_upper) = self.a.size_hint();
-        let (b_lower, b_upper) = self.b.size_hint();
-
-        let lower = a_lower.saturating_add(b_lower);
-
-        let upper = match (a_upper, b_upper) {
-            (Some(x), Some(y)) => x.checked_add(&y),
-            _ => None
-        };
-
-        (lower, upper)
-    }
-}
-
-impl<A, T: DoubleEndedIterator<A>, U: DoubleEndedIterator<A>> DoubleEndedIterator<A>
-for Chain<T, U> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> {
-        match self.b.next_back() {
-            Some(x) => Some(x),
-            None => self.a.next_back()
-        }
-    }
-}
-
-impl<A, T: RandomAccessIterator<A>, U: RandomAccessIterator<A>> RandomAccessIterator<A>
-for Chain<T, U> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        let (a, b) = (self.a.indexable(), self.b.indexable());
-        a.saturating_add(b)
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<A> {
-        let len = self.a.indexable();
-        if index < len {
-            self.a.idx(index)
-        } else {
-            self.b.idx(index - len)
-        }
-    }
-}
-
-/// An iterator which iterates two other iterators simultaneously
-#[deriving(Clone)]
-pub struct Zip<T, U> {
-    a: T,
-    b: U
-}
-
-impl<A, B, T: Iterator<A>, U: Iterator<B>> Iterator<(A, B)> for Zip<T, U> {
-    #[inline]
-    fn next(&mut self) -> Option<(A, B)> {
-        match self.a.next() {
-            None => None,
-            Some(x) => match self.b.next() {
-                None => None,
-                Some(y) => Some((x, y))
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (a_lower, a_upper) = self.a.size_hint();
-        let (b_lower, b_upper) = self.b.size_hint();
-
-        let lower = cmp::min(a_lower, b_lower);
-
-        let upper = match (a_upper, b_upper) {
-            (Some(x), Some(y)) => Some(cmp::min(x,y)),
-            (Some(x), None) => Some(x),
-            (None, Some(y)) => Some(y),
-            (None, None) => None
-        };
-
-        (lower, upper)
-    }
-}
-
-impl<A, B, T: ExactSize<A>, U: ExactSize<B>> DoubleEndedIterator<(A, B)>
-for Zip<T, U> {
-    #[inline]
-    fn next_back(&mut self) -> Option<(A, B)> {
-        let (a_sz, a_upper) = self.a.size_hint();
-        let (b_sz, b_upper) = self.b.size_hint();
-        assert!(a_upper == Some(a_sz));
-        assert!(b_upper == Some(b_sz));
-        if a_sz < b_sz {
-            for _ in range(0, b_sz - a_sz) { self.b.next_back(); }
-        } else if a_sz > b_sz {
-            for _ in range(0, a_sz - b_sz) { self.a.next_back(); }
-        }
-        let (a_sz, _) = self.a.size_hint();
-        let (b_sz, _) = self.b.size_hint();
-        assert!(a_sz == b_sz);
-        match (self.a.next_back(), self.b.next_back()) {
-            (Some(x), Some(y)) => Some((x, y)),
-            _ => None
-        }
-    }
-}
-
-impl<A, B, T: RandomAccessIterator<A>, U: RandomAccessIterator<B>>
-RandomAccessIterator<(A, B)> for Zip<T, U> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        cmp::min(self.a.indexable(), self.b.indexable())
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<(A, B)> {
-        match self.a.idx(index) {
-            None => None,
-            Some(x) => match self.b.idx(index) {
-                None => None,
-                Some(y) => Some((x, y))
-            }
-        }
-    }
-}
-
-/// An iterator which maps the values of `iter` with `f`
-pub struct Map<'a, A, B, T> {
-    iter: T,
-    f: |A|: 'a -> B
-}
-
-impl<'a, A, B, T> Map<'a, A, B, T> {
-    #[inline]
-    fn do_map(&mut self, elt: Option<A>) -> Option<B> {
-        match elt {
-            Some(a) => Some((self.f)(a)),
-            _ => None
-        }
-    }
-}
-
-impl<'a, A, B, T: Iterator<A>> Iterator<B> for Map<'a, A, B, T> {
-    #[inline]
-    fn next(&mut self) -> Option<B> {
-        let next = self.iter.next();
-        self.do_map(next)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        self.iter.size_hint()
-    }
-}
-
-impl<'a, A, B, T: DoubleEndedIterator<A>> DoubleEndedIterator<B> for Map<'a, A, B, T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<B> {
-        let next = self.iter.next_back();
-        self.do_map(next)
-    }
-}
-
-impl<'a, A, B, T: RandomAccessIterator<A>> RandomAccessIterator<B> for Map<'a, A, B, T> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        self.iter.indexable()
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<B> {
-        let elt = self.iter.idx(index);
-        self.do_map(elt)
-    }
-}
-
-/// An iterator which filters the elements of `iter` with `predicate`
-pub struct Filter<'a, A, T> {
-    iter: T,
-    predicate: |&A|: 'a -> bool
-}
-
-impl<'a, A, T: Iterator<A>> Iterator<A> for Filter<'a, A, T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        for x in self.iter {
-            if (self.predicate)(&x) {
-                return Some(x);
-            } else {
-                continue
-            }
-        }
-        None
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the predicate
-    }
-}
-
-impl<'a, A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for Filter<'a, A, T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> {
-        loop {
-            match self.iter.next_back() {
-                None => return None,
-                Some(x) => {
-                    if (self.predicate)(&x) {
-                        return Some(x);
-                    } else {
-                        continue
-                    }
-                }
-            }
-        }
-    }
-}
-
-/// An iterator which uses `f` to both filter and map elements from `iter`
-pub struct FilterMap<'a, A, B, T> {
-    iter: T,
-    f: |A|: 'a -> Option<B>
-}
-
-impl<'a, A, B, T: Iterator<A>> Iterator<B> for FilterMap<'a, A, B, T> {
-    #[inline]
-    fn next(&mut self) -> Option<B> {
-        for x in self.iter {
-            match (self.f)(x) {
-                Some(y) => return Some(y),
-                None => ()
-            }
-        }
-        None
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the predicate
-    }
-}
-
-impl<'a, A, B, T: DoubleEndedIterator<A>> DoubleEndedIterator<B>
-for FilterMap<'a, A, B, T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<B> {
-        loop {
-            match self.iter.next_back() {
-                None => return None,
-                Some(x) => {
-                    match (self.f)(x) {
-                        Some(y) => return Some(y),
-                        None => ()
-                    }
-                }
-            }
-        }
-    }
-}
-
-/// An iterator which yields the current count and the element during iteration
-#[deriving(Clone)]
-pub struct Enumerate<T> {
-    iter: T,
-    count: uint
-}
-
-impl<A, T: Iterator<A>> Iterator<(uint, A)> for Enumerate<T> {
-    #[inline]
-    fn next(&mut self) -> Option<(uint, A)> {
-        match self.iter.next() {
-            Some(a) => {
-                let ret = Some((self.count, a));
-                self.count += 1;
-                ret
-            }
-            _ => None
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        self.iter.size_hint()
-    }
-}
-
-impl<A, T: ExactSize<A>> DoubleEndedIterator<(uint, A)> for Enumerate<T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<(uint, A)> {
-        match self.iter.next_back() {
-            Some(a) => {
-                let (lower, upper) = self.iter.size_hint();
-                assert!(upper == Some(lower));
-                Some((self.count + lower, a))
-            }
-            _ => None
-        }
-    }
-}
-
-impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<(uint, A)> for Enumerate<T> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        self.iter.indexable()
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<(uint, A)> {
-        match self.iter.idx(index) {
-            Some(a) => Some((self.count + index, a)),
-            _ => None,
-        }
-    }
-}
-
-/// An iterator with a `peek()` that returns an optional reference to the next element.
-pub struct Peekable<A, T> {
-    iter: T,
-    peeked: Option<A>,
-}
-
-impl<A, T: Iterator<A>> Iterator<A> for Peekable<A, T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if self.peeked.is_some() { self.peeked.take() }
-        else { self.iter.next() }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (lo, hi) = self.iter.size_hint();
-        if self.peeked.is_some() {
-            let lo = lo.saturating_add(1);
-            let hi = match hi {
-                Some(x) => x.checked_add(&1),
-                None => None
-            };
-            (lo, hi)
-        } else {
-            (lo, hi)
-        }
-    }
-}
-
-impl<'a, A, T: Iterator<A>> Peekable<A, T> {
-    /// Return a reference to the next element of the iterator with out advancing it,
-    /// or None if the iterator is exhausted.
-    #[inline]
-    pub fn peek(&'a mut self) -> Option<&'a A> {
-        if self.peeked.is_none() {
-            self.peeked = self.iter.next();
-        }
-        match self.peeked {
-            Some(ref value) => Some(value),
-            None => None,
-        }
-    }
-
-    /// Check whether peekable iterator is empty or not.
-    #[inline]
-    pub fn is_empty(&mut self) -> bool {
-        self.peek().is_none()
-    }
-}
-
-/// An iterator which rejects elements while `predicate` is true
-pub struct SkipWhile<'a, A, T> {
-    iter: T,
-    flag: bool,
-    predicate: |&A|: 'a -> bool
-}
-
-impl<'a, A, T: Iterator<A>> Iterator<A> for SkipWhile<'a, A, T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        let mut next = self.iter.next();
-        if self.flag {
-            next
-        } else {
-            loop {
-                match next {
-                    Some(x) => {
-                        if (self.predicate)(&x) {
-                            next = self.iter.next();
-                            continue
-                        } else {
-                            self.flag = true;
-                            return Some(x)
-                        }
-                    }
-                    None => return None
-                }
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the predicate
-    }
-}
-
-/// An iterator which only accepts elements while `predicate` is true
-pub struct TakeWhile<'a, A, T> {
-    iter: T,
-    flag: bool,
-    predicate: |&A|: 'a -> bool
-}
-
-impl<'a, A, T: Iterator<A>> Iterator<A> for TakeWhile<'a, A, T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if self.flag {
-            None
-        } else {
-            match self.iter.next() {
-                Some(x) => {
-                    if (self.predicate)(&x) {
-                        Some(x)
-                    } else {
-                        self.flag = true;
-                        None
-                    }
-                }
-                None => None
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the predicate
-    }
-}
-
-/// An iterator which skips over `n` elements of `iter`.
-#[deriving(Clone)]
-pub struct Skip<T> {
-    iter: T,
-    n: uint
-}
-
-impl<A, T: Iterator<A>> Iterator<A> for Skip<T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        let mut next = self.iter.next();
-        if self.n == 0 {
-            next
-        } else {
-            let mut n = self.n;
-            while n > 0 {
-                n -= 1;
-                match next {
-                    Some(_) => {
-                        next = self.iter.next();
-                        continue
-                    }
-                    None => {
-                        self.n = 0;
-                        return None
-                    }
-                }
-            }
-            self.n = 0;
-            next
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (lower, upper) = self.iter.size_hint();
-
-        let lower = lower.saturating_sub(self.n);
-
-        let upper = match upper {
-            Some(x) => Some(x.saturating_sub(self.n)),
-            None => None
-        };
-
-        (lower, upper)
-    }
-}
-
-impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<A> for Skip<T> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        self.iter.indexable().saturating_sub(self.n)
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<A> {
-        if index >= self.indexable() {
-            None
-        } else {
-            self.iter.idx(index + self.n)
-        }
-    }
-}
-
-/// An iterator which only iterates over the first `n` iterations of `iter`.
-#[deriving(Clone)]
-pub struct Take<T> {
-    iter: T,
-    n: uint
-}
-
-impl<A, T: Iterator<A>> Iterator<A> for Take<T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if self.n != 0 {
-            self.n -= 1;
-            self.iter.next()
-        } else {
-            None
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (lower, upper) = self.iter.size_hint();
-
-        let lower = cmp::min(lower, self.n);
-
-        let upper = match upper {
-            Some(x) if x < self.n => Some(x),
-            _ => Some(self.n)
-        };
-
-        (lower, upper)
-    }
-}
-
-impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<A> for Take<T> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        cmp::min(self.iter.indexable(), self.n)
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<A> {
-        if index >= self.n {
-            None
-        } else {
-            self.iter.idx(index)
-        }
-    }
-}
-
-
-/// An iterator to maintain state while iterating another iterator
-pub struct Scan<'a, A, B, T, St> {
-    iter: T,
-    f: |&mut St, A|: 'a -> Option<B>,
-
-    /// The current internal state to be passed to the closure next.
-    pub state: St,
-}
-
-impl<'a, A, B, T: Iterator<A>, St> Iterator<B> for Scan<'a, A, B, T, St> {
-    #[inline]
-    fn next(&mut self) -> Option<B> {
-        self.iter.next().and_then(|a| (self.f)(&mut self.state, a))
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the scan function
-    }
-}
-
-/// An iterator that maps each element to an iterator,
-/// and yields the elements of the produced iterators
-///
-pub struct FlatMap<'a, A, T, U> {
-    iter: T,
-    f: |A|: 'a -> U,
-    frontiter: Option<U>,
-    backiter: Option<U>,
-}
-
-impl<'a, A, T: Iterator<A>, B, U: Iterator<B>> Iterator<B> for FlatMap<'a, A, T, U> {
-    #[inline]
-    fn next(&mut self) -> Option<B> {
-        loop {
-            for inner in self.frontiter.mut_iter() {
-                for x in *inner {
-                    return Some(x)
-                }
-            }
-            match self.iter.next().map(|x| (self.f)(x)) {
-                None => return self.backiter.as_mut().and_then(|it| it.next()),
-                next => self.frontiter = next,
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (flo, fhi) = self.frontiter.as_ref().map_or((0, Some(0)), |it| it.size_hint());
-        let (blo, bhi) = self.backiter.as_ref().map_or((0, Some(0)), |it| it.size_hint());
-        let lo = flo.saturating_add(blo);
-        match (self.iter.size_hint(), fhi, bhi) {
-            ((0, Some(0)), Some(a), Some(b)) => (lo, a.checked_add(&b)),
-            _ => (lo, None)
-        }
-    }
-}
-
-impl<'a,
-     A, T: DoubleEndedIterator<A>,
-     B, U: DoubleEndedIterator<B>> DoubleEndedIterator<B>
-     for FlatMap<'a, A, T, U> {
-    #[inline]
-    fn next_back(&mut self) -> Option<B> {
-        loop {
-            for inner in self.backiter.mut_iter() {
-                match inner.next_back() {
-                    None => (),
-                    y => return y
-                }
-            }
-            match self.iter.next_back().map(|x| (self.f)(x)) {
-                None => return self.frontiter.as_mut().and_then(|it| it.next_back()),
-                next => self.backiter = next,
-            }
-        }
-    }
-}
-
-/// An iterator that yields `None` forever after the underlying iterator
-/// yields `None` once.
-#[deriving(Clone)]
-pub struct Fuse<T> {
-    iter: T,
-    done: bool
-}
-
-impl<A, T: Iterator<A>> Iterator<A> for Fuse<T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if self.done {
-            None
-        } else {
-            match self.iter.next() {
-                None => {
-                    self.done = true;
-                    None
-                }
-                x => x
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        if self.done {
-            (0, Some(0))
-        } else {
-            self.iter.size_hint()
-        }
-    }
-}
-
-impl<A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for Fuse<T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> {
-        if self.done {
-            None
-        } else {
-            match self.iter.next_back() {
-                None => {
-                    self.done = true;
-                    None
-                }
-                x => x
-            }
-        }
-    }
-}
-
-// Allow RandomAccessIterators to be fused without affecting random-access behavior
-impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<A> for Fuse<T> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        self.iter.indexable()
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<A> {
-        self.iter.idx(index)
-    }
-}
-
-impl<T> Fuse<T> {
-    /// Resets the fuse such that the next call to .next() or .next_back() will
-    /// call the underlying iterator again even if it previously returned None.
-    #[inline]
-    pub fn reset_fuse(&mut self) {
-        self.done = false
-    }
-}
-
-/// An iterator that calls a function with a reference to each
-/// element before yielding it.
-pub struct Inspect<'a, A, T> {
-    iter: T,
-    f: |&A|: 'a
-}
-
-impl<'a, A, T> Inspect<'a, A, T> {
-    #[inline]
-    fn do_inspect(&mut self, elt: Option<A>) -> Option<A> {
-        match elt {
-            Some(ref a) => (self.f)(a),
-            None => ()
-        }
-
-        elt
-    }
-}
-
-impl<'a, A, T: Iterator<A>> Iterator<A> for Inspect<'a, A, T> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        let next = self.iter.next();
-        self.do_inspect(next)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        self.iter.size_hint()
-    }
-}
-
-impl<'a, A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A>
-for Inspect<'a, A, T> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> {
-        let next = self.iter.next_back();
-        self.do_inspect(next)
-    }
-}
-
-impl<'a, A, T: RandomAccessIterator<A>> RandomAccessIterator<A>
-for Inspect<'a, A, T> {
-    #[inline]
-    fn indexable(&self) -> uint {
-        self.iter.indexable()
-    }
-
-    #[inline]
-    fn idx(&mut self, index: uint) -> Option<A> {
-        let element = self.iter.idx(index);
-        self.do_inspect(element)
-    }
-}
-
-/// An iterator which just modifies the contained state throughout iteration.
-pub struct Unfold<'a, A, St> {
-    f: |&mut St|: 'a -> Option<A>,
-    /// Internal state that will be yielded on the next iteration
-    pub state: St,
-}
-
-impl<'a, A, St> Unfold<'a, A, St> {
-    /// Creates a new iterator with the specified closure as the "iterator
-    /// function" and an initial state to eventually pass to the iterator
-    #[inline]
-    pub fn new<'a>(initial_state: St, f: |&mut St|: 'a -> Option<A>)
-               -> Unfold<'a, A, St> {
-        Unfold {
-            f: f,
-            state: initial_state
-        }
-    }
-}
-
-impl<'a, A, St> Iterator<A> for Unfold<'a, A, St> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        (self.f)(&mut self.state)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        // no possible known bounds at this point
-        (0, None)
-    }
-}
-
-/// An infinite iterator starting at `start` and advancing by `step` with each
-/// iteration
-#[deriving(Clone)]
-pub struct Counter<A> {
-    /// The current state the counter is at (next value to be yielded)
-    state: A,
-    /// The amount that this iterator is stepping by
-    step: A,
-}
-
-/// Creates a new counter with the specified start/step
-#[inline]
-pub fn count<A>(start: A, step: A) -> Counter<A> {
-    Counter{state: start, step: step}
-}
-
-impl<A: Add<A, A> + Clone> Iterator<A> for Counter<A> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        let result = self.state.clone();
-        self.state = self.state + self.step;
-        Some(result)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        (uint::MAX, None) // Too bad we can't specify an infinite lower bound
-    }
-}
-
-/// An iterator over the range [start, stop)
-#[deriving(Clone)]
-pub struct Range<A> {
-    state: A,
-    stop: A,
-    one: A
-}
-
-/// Return an iterator over the range [start, stop)
-#[inline]
-pub fn range<A: Add<A, A> + Ord + Clone + One>(start: A, stop: A) -> Range<A> {
-    Range{state: start, stop: stop, one: One::one()}
-}
-
-// FIXME: #10414: Unfortunate type bound
-impl<A: Add<A, A> + Ord + Clone + ToPrimitive> Iterator<A> for Range<A> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if self.state < self.stop {
-            let result = self.state.clone();
-            self.state = self.state + self.one;
-            Some(result)
-        } else {
-            None
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        // This first checks if the elements are representable as i64. If they aren't, try u64 (to
-        // handle cases like range(huge, huger)). We don't use uint/int because the difference of
-        // the i64/u64 might lie within their range.
-        let bound = match self.state.to_i64() {
-            Some(a) => {
-                let sz = self.stop.to_i64().map(|b| b.checked_sub(&a));
-                match sz {
-                    Some(Some(bound)) => bound.to_uint(),
-                    _ => None,
-                }
-            },
-            None => match self.state.to_u64() {
-                Some(a) => {
-                    let sz = self.stop.to_u64().map(|b| b.checked_sub(&a));
-                    match sz {
-                        Some(Some(bound)) => bound.to_uint(),
-                        _ => None
-                    }
-                },
-                None => None
-            }
-        };
-
-        match bound {
-            Some(b) => (b, Some(b)),
-            // Standard fallback for unbounded/unrepresentable bounds
-            None => (0, None)
-        }
-    }
-}
-
-/// `Int` is required to ensure the range will be the same regardless of
-/// the direction it is consumed.
-impl<A: Int + Ord + Clone + ToPrimitive> DoubleEndedIterator<A> for Range<A> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> {
-        if self.stop > self.state {
-            self.stop = self.stop - self.one;
-            Some(self.stop.clone())
-        } else {
-            None
-        }
-    }
-}
-
-/// An iterator over the range [start, stop]
-#[deriving(Clone)]
-pub struct RangeInclusive<A> {
-    range: Range<A>,
-    done: bool,
-}
-
-/// Return an iterator over the range [start, stop]
-#[inline]
-pub fn range_inclusive<A: Add<A, A> + Ord + Clone + One + ToPrimitive>(start: A, stop: A)
-    -> RangeInclusive<A> {
-    RangeInclusive{range: range(start, stop), done: false}
-}
-
-impl<A: Add<A, A> + Ord + Clone + ToPrimitive> Iterator<A> for RangeInclusive<A> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        match self.range.next() {
-            Some(x) => Some(x),
-            None => {
-                if !self.done && self.range.state == self.range.stop {
-                    self.done = true;
-                    Some(self.range.stop.clone())
-                } else {
-                    None
-                }
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) {
-        let (lo, hi) = self.range.size_hint();
-        if self.done {
-            (lo, hi)
-        } else {
-            let lo = lo.saturating_add(1);
-            let hi = match hi {
-                Some(x) => x.checked_add(&1),
-                None => None
-            };
-            (lo, hi)
-        }
-    }
-}
-
-impl<A: Sub<A, A> + Int + Ord + Clone + ToPrimitive> DoubleEndedIterator<A>
-    for RangeInclusive<A> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> {
-        if self.range.stop > self.range.state {
-            let result = self.range.stop.clone();
-            self.range.stop = self.range.stop - self.range.one;
-            Some(result)
-        } else if !self.done && self.range.state == self.range.stop {
-            self.done = true;
-            Some(self.range.stop.clone())
-        } else {
-            None
-        }
-    }
-}
-
-/// An iterator over the range [start, stop) by `step`. It handles overflow by stopping.
-#[deriving(Clone)]
-pub struct RangeStep<A> {
-    state: A,
-    stop: A,
-    step: A,
-    rev: bool,
-}
-
-/// Return an iterator over the range [start, stop) by `step`. It handles overflow by stopping.
-#[inline]
-pub fn range_step<A: CheckedAdd + Ord + Clone + Zero>(start: A, stop: A, step: A) -> RangeStep<A> {
-    let rev = step < Zero::zero();
-    RangeStep{state: start, stop: stop, step: step, rev: rev}
-}
-
-impl<A: CheckedAdd + Ord + Clone> Iterator<A> for RangeStep<A> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if (self.rev && self.state > self.stop) || (!self.rev && self.state < self.stop) {
-            let result = self.state.clone();
-            match self.state.checked_add(&self.step) {
-                Some(x) => self.state = x,
-                None => self.state = self.stop.clone()
-            }
-            Some(result)
-        } else {
-            None
-        }
-    }
-}
-
-/// An iterator over the range [start, stop] by `step`. It handles overflow by stopping.
-#[deriving(Clone)]
-pub struct RangeStepInclusive<A> {
-    state: A,
-    stop: A,
-    step: A,
-    rev: bool,
-    done: bool,
-}
-
-/// Return an iterator over the range [start, stop] by `step`. It handles overflow by stopping.
-#[inline]
-pub fn range_step_inclusive<A: CheckedAdd + Ord + Clone + Zero>(start: A, stop: A,
-                                                                step: A) -> RangeStepInclusive<A> {
-    let rev = step < Zero::zero();
-    RangeStepInclusive{state: start, stop: stop, step: step, rev: rev, done: false}
-}
-
-impl<A: CheckedAdd + Ord + Clone + Eq> Iterator<A> for RangeStepInclusive<A> {
-    #[inline]
-    fn next(&mut self) -> Option<A> {
-        if !self.done && ((self.rev && self.state >= self.stop) ||
-                          (!self.rev && self.state <= self.stop)) {
-            let result = self.state.clone();
-            match self.state.checked_add(&self.step) {
-                Some(x) => self.state = x,
-                None => self.done = true
-            }
-            Some(result)
-        } else {
-            None
-        }
-    }
-}
-
-/// An iterator that repeats an element endlessly
-#[deriving(Clone)]
-pub struct Repeat<A> {
-    element: A
-}
-
-impl<A: Clone> Repeat<A> {
-    /// Create a new `Repeat` that endlessly repeats the element `elt`.
-    #[inline]
-    pub fn new(elt: A) -> Repeat<A> {
-        Repeat{element: elt}
-    }
-}
-
-impl<A: Clone> Iterator<A> for Repeat<A> {
-    #[inline]
-    fn next(&mut self) -> Option<A> { self.idx(0) }
-    #[inline]
-    fn size_hint(&self) -> (uint, Option<uint>) { (uint::MAX, None) }
-}
-
-impl<A: Clone> DoubleEndedIterator<A> for Repeat<A> {
-    #[inline]
-    fn next_back(&mut self) -> Option<A> { self.idx(0) }
-}
-
-impl<A: Clone> RandomAccessIterator<A> for Repeat<A> {
-    #[inline]
-    fn indexable(&self) -> uint { uint::MAX }
-    #[inline]
-    fn idx(&mut self, _: uint) -> Option<A> { Some(self.element.clone()) }
-}
-
-/// Functions for lexicographical ordering of sequences.
-///
-/// Lexicographical ordering through `<`, `<=`, `>=`, `>` requires
-/// that the elements implement both `Eq` and `Ord`.
-///
-/// If two sequences are equal up until the point where one ends,
-/// the shorter sequence compares less.
-pub mod order {
-    use cmp;
-    use cmp::{TotalEq, TotalOrd, Ord, Eq};
-    use option::{Some, None};
-    use super::Iterator;
-
-    /// Compare `a` and `b` for equality using `TotalEq`
-    pub fn equals<A: TotalEq, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return true,
-                (None, _) | (_, None) => return false,
-                (Some(x), Some(y)) => if x != y { return false },
-            }
-        }
-    }
-
-    /// Order `a` and `b` lexicographically using `TotalOrd`
-    pub fn cmp<A: TotalOrd, T: Iterator<A>>(mut a: T, mut b: T) -> cmp::Ordering {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return cmp::Equal,
-                (None, _   ) => return cmp::Less,
-                (_   , None) => return cmp::Greater,
-                (Some(x), Some(y)) => match x.cmp(&y) {
-                    cmp::Equal => (),
-                    non_eq => return non_eq,
-                },
-            }
-        }
-    }
-
-    /// Compare `a` and `b` for equality (Using partial equality, `Eq`)
-    pub fn eq<A: Eq, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return true,
-                (None, _) | (_, None) => return false,
-                (Some(x), Some(y)) => if !x.eq(&y) { return false },
-            }
-        }
-    }
-
-    /// Compare `a` and `b` for nonequality (Using partial equality, `Eq`)
-    pub fn ne<A: Eq, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return false,
-                (None, _) | (_, None) => return true,
-                (Some(x), Some(y)) => if x.ne(&y) { return true },
-            }
-        }
-    }
-
-    /// Return `a` < `b` lexicographically (Using partial order, `Ord`)
-    pub fn lt<A: Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return false,
-                (None, _   ) => return true,
-                (_   , None) => return false,
-                (Some(x), Some(y)) => if x.ne(&y) { return x.lt(&y) },
-            }
-        }
-    }
-
-    /// Return `a` <= `b` lexicographically (Using partial order, `Ord`)
-    pub fn le<A: Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return true,
-                (None, _   ) => return true,
-                (_   , None) => return false,
-                (Some(x), Some(y)) => if x.ne(&y) { return x.le(&y) },
-            }
-        }
-    }
-
-    /// Return `a` > `b` lexicographically (Using partial order, `Ord`)
-    pub fn gt<A: Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return false,
-                (None, _   ) => return false,
-                (_   , None) => return true,
-                (Some(x), Some(y)) => if x.ne(&y) { return x.gt(&y) },
-            }
-        }
-    }
-
-    /// Return `a` >= `b` lexicographically (Using partial order, `Ord`)
-    pub fn ge<A: Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
-        loop {
-            match (a.next(), b.next()) {
-                (None, None) => return true,
-                (None, _   ) => return false,
-                (_   , None) => return true,
-                (Some(x), Some(y)) => if x.ne(&y) { return x.ge(&y) },
-            }
-        }
-    }
-
-    #[test]
-    fn test_lt() {
-        use slice::ImmutableVector;
-
-        let empty: [int, ..0] = [];
-        let xs = [1,2,3];
-        let ys = [1,2,0];
-
-        assert!(!lt(xs.iter(), ys.iter()));
-        assert!(!le(xs.iter(), ys.iter()));
-        assert!( gt(xs.iter(), ys.iter()));
-        assert!( ge(xs.iter(), ys.iter()));
-
-        assert!( lt(ys.iter(), xs.iter()));
-        assert!( le(ys.iter(), xs.iter()));
-        assert!(!gt(ys.iter(), xs.iter()));
-        assert!(!ge(ys.iter(), xs.iter()));
-
-        assert!( lt(empty.iter(), xs.iter()));
-        assert!( le(empty.iter(), xs.iter()));
-        assert!(!gt(empty.iter(), xs.iter()));
-        assert!(!ge(empty.iter(), xs.iter()));
-
-        // Sequence with NaN
-        let u = [1.0, 2.0];
-        let v = [0.0/0.0, 3.0];
-
-        assert!(!lt(u.iter(), v.iter()));
-        assert!(!le(u.iter(), v.iter()));
-        assert!(!gt(u.iter(), v.iter()));
-        assert!(!ge(u.iter(), v.iter()));
-
-        let a = [0.0/0.0];
-        let b = [1.0];
-        let c = [2.0];
-
-        assert!(lt(a.iter(), b.iter()) == (a[0] <  b[0]));
-        assert!(le(a.iter(), b.iter()) == (a[0] <= b[0]));
-        assert!(gt(a.iter(), b.iter()) == (a[0] >  b[0]));
-        assert!(ge(a.iter(), b.iter()) == (a[0] >= b[0]));
-
-        assert!(lt(c.iter(), b.iter()) == (c[0] <  b[0]));
-        assert!(le(c.iter(), b.iter()) == (c[0] <= b[0]));
-        assert!(gt(c.iter(), b.iter()) == (c[0] >  b[0]));
-        assert!(ge(c.iter(), b.iter()) == (c[0] >= b[0]));
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use prelude::*;
-
-    use cmp;
-    use owned::Box;
-    use uint;
-    use num;
-
-    #[test]
-    fn test_counter_from_iter() {
-        let it = count(0, 5).take(10);
-        let xs: ~[int] = FromIterator::from_iter(it);
-        assert_eq!(xs, box [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
-    }
-
-    #[test]
-    fn test_iterator_chain() {
-        let xs = [0u, 1, 2, 3, 4, 5];
-        let ys = [30u, 40, 50, 60];
-        let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
-        let mut it = xs.iter().chain(ys.iter());
-        let mut i = 0;
-        for &x in it {
-            assert_eq!(x, expected[i]);
-            i += 1;
-        }
-        assert_eq!(i, expected.len());
-
-        let ys = count(30u, 10).take(4);
-        let mut it = xs.iter().map(|&x| x).chain(ys);
-        let mut i = 0;
-        for x in it {
-            assert_eq!(x, expected[i]);
-            i += 1;
-        }
-        assert_eq!(i, expected.len());
-    }
-
-    #[test]
-    fn test_filter_map() {
-        let mut it = count(0u, 1u).take(10)
-            .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
-        assert_eq!(it.collect::<~[uint]>(), box [0*0, 2*2, 4*4, 6*6, 8*8]);
-    }
-
-    #[test]
-    fn test_iterator_enumerate() {
-        let xs = [0u, 1, 2, 3, 4, 5];
-        let mut it = xs.iter().enumerate();
-        for (i, &x) in it {
-            assert_eq!(i, x);
-        }
-    }
-
-    #[test]
-    fn test_iterator_peekable() {
-        let xs = box [0u, 1, 2, 3, 4, 5];
-        let mut it = xs.iter().map(|&x|x).peekable();
-        assert_eq!(it.peek().unwrap(), &0);
-        assert_eq!(it.next().unwrap(), 0);
-        assert_eq!(it.next().unwrap(), 1);
-        assert_eq!(it.next().unwrap(), 2);
-        assert_eq!(it.peek().unwrap(), &3);
-        assert_eq!(it.peek().unwrap(), &3);
-        assert_eq!(it.next().unwrap(), 3);
-        assert_eq!(it.next().unwrap(), 4);
-        assert_eq!(it.peek().unwrap(), &5);
-        assert_eq!(it.next().unwrap(), 5);
-        assert!(it.peek().is_none());
-        assert!(it.next().is_none());
-    }
-
-    #[test]
-    fn test_iterator_take_while() {
-        let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19];
-        let ys = [0u, 1, 2, 3, 5, 13];
-        let mut it = xs.iter().take_while(|&x| *x < 15u);
-        let mut i = 0;
-        for &x in it {
-            assert_eq!(x, ys[i]);
-            i += 1;
-        }
-        assert_eq!(i, ys.len());
-    }
-
-    #[test]
-    fn test_iterator_skip_while() {
-        let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19];
-        let ys = [15, 16, 17, 19];
-        let mut it = xs.iter().skip_while(|&x| *x < 15u);
-        let mut i = 0;
-        for &x in it {
-            assert_eq!(x, ys[i]);
-            i += 1;
-        }
-        assert_eq!(i, ys.len());
-    }
-
-    #[test]
-    fn test_iterator_skip() {
-        let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
-        let ys = [13, 15, 16, 17, 19, 20, 30];
-        let mut it = xs.iter().skip(5);
-        let mut i = 0;
-        for &x in it {
-            assert_eq!(x, ys[i]);
-            i += 1;
-        }
-        assert_eq!(i, ys.len());
-    }
-
-    #[test]
-    fn test_iterator_take() {
-        let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19];
-        let ys = [0u, 1, 2, 3, 5];
-        let mut it = xs.iter().take(5);
-        let mut i = 0;
-        for &x in it {
-            assert_eq!(x, ys[i]);
-            i += 1;
-        }
-        assert_eq!(i, ys.len());
-    }
-
-    #[test]
-    fn test_iterator_scan() {
-        // test the type inference
-        fn add(old: &mut int, new: &uint) -> Option<f64> {
-            *old += *new as int;
-            Some(*old as f64)
-        }
-        let xs = [0u, 1, 2, 3, 4];
-        let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
-
-        let mut it = xs.iter().scan(0, add);
-        let mut i = 0;
-        for x in it {
-            assert_eq!(x, ys[i]);
-            i += 1;
-        }
-        assert_eq!(i, ys.len());
-    }
-
-    #[test]
-    fn test_iterator_flat_map() {
-        let xs = [0u, 3, 6];
-        let ys = [0u, 1, 2, 3, 4, 5, 6, 7, 8];
-        let mut it = xs.iter().flat_map(|&x| count(x, 1).take(3));
-        let mut i = 0;
-        for x in it {
-            assert_eq!(x, ys[i]);
-            i += 1;
-        }
-        assert_eq!(i, ys.len());
-    }
-
-    #[test]
-    fn test_inspect() {
-        let xs = [1u, 2, 3, 4];
-        let mut n = 0;
-
-        let ys = xs.iter()
-                   .map(|&x| x)
-                   .inspect(|_| n += 1)
-                   .collect::<~[uint]>();
-
-        assert_eq!(n, xs.len());
-        assert_eq!(xs.as_slice(), ys.as_slice());
-    }
-
-    #[test]
-    fn test_unfoldr() {
-        fn count(st: &mut uint) -> Option<uint> {
-            if *st < 10 {
-                let ret = Some(*st);
-                *st += 1;
-                ret
-            } else {
-                None
-            }
-        }
-
-        let mut it = Unfold::new(0, count);
-        let mut i = 0;
-        for counted in it {
-            assert_eq!(counted, i);
-            i += 1;
-        }
-        assert_eq!(i, 10);
-    }
-
-    #[test]
-    fn test_cycle() {
-        let cycle_len = 3;
-        let it = count(0u, 1).take(cycle_len).cycle();
-        assert_eq!(it.size_hint(), (uint::MAX, None));
-        for (i, x) in it.take(100).enumerate() {
-            assert_eq!(i % cycle_len, x);
-        }
-
-        let mut it = count(0u, 1).take(0).cycle();
-        assert_eq!(it.size_hint(), (0, Some(0)));
-        assert_eq!(it.next(), None);
-    }
-
-    #[test]
-    fn test_iterator_nth() {
-        let v = &[0, 1, 2, 3, 4];
-        for i in range(0u, v.len()) {
-            assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
-        }
-    }
-
-    #[test]
-    fn test_iterator_last() {
-        let v = &[0, 1, 2, 3, 4];
-        assert_eq!(v.iter().last().unwrap(), &4);
-        assert_eq!(v.slice(0, 1).iter().last().unwrap(), &0);
-    }
-
-    #[test]
-    fn test_iterator_len() {
-        let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-        assert_eq!(v.slice(0, 4).iter().len(), 4);
-        assert_eq!(v.slice(0, 10).iter().len(), 10);
-        assert_eq!(v.slice(0, 0).iter().len(), 0);
-    }
-
-    #[test]
-    fn test_iterator_sum() {
-        let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-        assert_eq!(v.slice(0, 4).iter().map(|&x| x).sum(), 6);
-        assert_eq!(v.iter().map(|&x| x).sum(), 55);
-        assert_eq!(v.slice(0, 0).iter().map(|&x| x).sum(), 0);
-    }
-
-    #[test]
-    fn test_iterator_product() {
-        let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-        assert_eq!(v.slice(0, 4).iter().map(|&x| x).product(), 0);
-        assert_eq!(v.slice(1, 5).iter().map(|&x| x).product(), 24);
-        assert_eq!(v.slice(0, 0).iter().map(|&x| x).product(), 1);
-    }
-
-    #[test]
-    fn test_iterator_max() {
-        let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-        assert_eq!(v.slice(0, 4).iter().map(|&x| x).max(), Some(3));
-        assert_eq!(v.iter().map(|&x| x).max(), Some(10));
-        assert_eq!(v.slice(0, 0).iter().map(|&x| x).max(), None);
-    }
-
-    #[test]
-    fn test_iterator_min() {
-        let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-        assert_eq!(v.slice(0, 4).iter().map(|&x| x).min(), Some(0));
-        assert_eq!(v.iter().map(|&x| x).min(), Some(0));
-        assert_eq!(v.slice(0, 0).iter().map(|&x| x).min(), None);
-    }
-
-    #[test]
-    fn test_iterator_size_hint() {
-        let c = count(0, 1);
-        let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
-        let v2 = &[10, 11, 12];
-        let vi = v.iter();
-
-        assert_eq!(c.size_hint(), (uint::MAX, None));
-        assert_eq!(vi.size_hint(), (10, Some(10)));
-
-        assert_eq!(c.take(5).size_hint(), (5, Some(5)));
-        assert_eq!(c.skip(5).size_hint().val1(), None);
-        assert_eq!(c.take_while(|_| false).size_hint(), (0, None));
-        assert_eq!(c.skip_while(|_| false).size_hint(), (0, None));
-        assert_eq!(c.enumerate().size_hint(), (uint::MAX, None));
-        assert_eq!(c.chain(vi.map(|&i| i)).size_hint(), (uint::MAX, None));
-        assert_eq!(c.zip(vi).size_hint(), (10, Some(10)));
-        assert_eq!(c.scan(0, |_,_| Some(0)).size_hint(), (0, None));
-        assert_eq!(c.filter(|_| false).size_hint(), (0, None));
-        assert_eq!(c.map(|_| 0).size_hint(), (uint::MAX, None));
-        assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
-
-        assert_eq!(vi.take(5).size_hint(), (5, Some(5)));
-        assert_eq!(vi.take(12).size_hint(), (10, Some(10)));
-        assert_eq!(vi.skip(3).size_hint(), (7, Some(7)));
-        assert_eq!(vi.skip(12).size_hint(), (0, Some(0)));
-        assert_eq!(vi.take_while(|_| false).size_hint(), (0, Some(10)));
-        assert_eq!(vi.skip_while(|_| false).size_hint(), (0, Some(10)));
-        assert_eq!(vi.enumerate().size_hint(), (10, Some(10)));
-        assert_eq!(vi.chain(v2.iter()).size_hint(), (13, Some(13)));
-        assert_eq!(vi.zip(v2.iter()).size_hint(), (3, Some(3)));
-        assert_eq!(vi.scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
-        assert_eq!(vi.filter(|_| false).size_hint(), (0, Some(10)));
-        assert_eq!(vi.map(|i| i+1).size_hint(), (10, Some(10)));
-        assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
-    }
-
-    #[test]
-    fn test_collect() {
-        let a = box [1, 2, 3, 4, 5];
-        let b: ~[int] = a.iter().map(|&x| x).collect();
-        assert_eq!(a, b);
-    }
-
-    #[test]
-    fn test_all() {
-        let v: Box<&[int]> = box &[1, 2, 3, 4, 5];
-        assert!(v.iter().all(|&x| x < 10));
-        assert!(!v.iter().all(|&x| x % 2 == 0));
-        assert!(!v.iter().all(|&x| x > 100));
-        assert!(v.slice(0, 0).iter().all(|_| fail!()));
-    }
-
-    #[test]
-    fn test_any() {
-        let v: Box<&[int]> = box &[1, 2, 3, 4, 5];
-        assert!(v.iter().any(|&x| x < 10));
-        assert!(v.iter().any(|&x| x % 2 == 0));
-        assert!(!v.iter().any(|&x| x > 100));
-        assert!(!v.slice(0, 0).iter().any(|_| fail!()));
-    }
-
-    #[test]
-    fn test_find() {
-        let v: &[int] = &[1, 3, 9, 27, 103, 14, 11];
-        assert_eq!(*v.iter().find(|x| *x & 1 == 0).unwrap(), 14);
-        assert_eq!(*v.iter().find(|x| *x % 3 == 0).unwrap(), 3);
-        assert!(v.iter().find(|x| *x % 12 == 0).is_none());
-    }
-
-    #[test]
-    fn test_position() {
-        let v = &[1, 3, 9, 27, 103, 14, 11];
-        assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
-        assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
-        assert!(v.iter().position(|x| *x % 12 == 0).is_none());
-    }
-
-    #[test]
-    fn test_count() {
-        let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
-        assert_eq!(xs.iter().count(|x| *x == 2), 3);
-        assert_eq!(xs.iter().count(|x| *x == 5), 1);
-        assert_eq!(xs.iter().count(|x| *x == 95), 0);
-    }
-
-    #[test]
-    fn test_max_by() {
-        let xs: &[int] = &[-3, 0, 1, 5, -10];
-        assert_eq!(*xs.iter().max_by(|x| x.abs()).unwrap(), -10);
-    }
-
-    #[test]
-    fn test_min_by() {
-        let xs: &[int] = &[-3, 0, 1, 5, -10];
-        assert_eq!(*xs.iter().min_by(|x| x.abs()).unwrap(), 0);
-    }
-
-    #[test]
-    fn test_by_ref() {
-        let mut xs = range(0, 10);
-        // sum the first five values
-        let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
-        assert_eq!(partial_sum, 10);
-        assert_eq!(xs.next(), Some(5));
-    }
-
-    #[test]
-    fn test_rev() {
-        let xs = [2, 4, 6, 8, 10, 12, 14, 16];
-        let mut it = xs.iter();
-        it.next();
-        it.next();
-        assert_eq!(it.rev().map(|&x| x).collect::<~[int]>(), box [16, 14, 12, 10, 8, 6]);
-    }
-
-    #[test]
-    fn test_double_ended_map() {
-        let xs = [1, 2, 3, 4, 5, 6];
-        let mut it = xs.iter().map(|&x| x * -1);
-        assert_eq!(it.next(), Some(-1));
-        assert_eq!(it.next(), Some(-2));
-        assert_eq!(it.next_back(), Some(-6));
-        assert_eq!(it.next_back(), Some(-5));
-        assert_eq!(it.next(), Some(-3));
-        assert_eq!(it.next_back(), Some(-4));
-        assert_eq!(it.next(), None);
-    }
-
-    #[test]
-    fn test_double_ended_enumerate() {
-        let xs = [1, 2, 3, 4, 5, 6];
-        let mut it = xs.iter().map(|&x| x).enumerate();
-        assert_eq!(it.next(), Some((0, 1)));
-        assert_eq!(it.next(), Some((1, 2)));
-        assert_eq!(it.next_back(), Some((5, 6)));
-        assert_eq!(it.next_back(), Some((4, 5)));
-        assert_eq!(it.next_back(), Some((3, 4)));
-        assert_eq!(it.next_back(), Some((2, 3)));
-        assert_eq!(it.next(), None);
-    }
-
-    #[test]
-    fn test_double_ended_zip() {
-        let xs = [1, 2, 3, 4, 5, 6];
-        let ys = [1, 2, 3, 7];
-        let a = xs.iter().map(|&x| x);
-        let b = ys.iter().map(|&x| x);
-        let mut it = a.zip(b);
-        assert_eq!(it.next(), Some((1, 1)));
-        assert_eq!(it.next(), Some((2, 2)));
-        assert_eq!(it.next_back(), Some((4, 7)));
-        assert_eq!(it.next_back(), Some((3, 3)));
-        assert_eq!(it.next(), None);
-    }
-
-    #[test]
-    fn test_double_ended_filter() {
-        let xs = [1, 2, 3, 4, 5, 6];
-        let mut it = xs.iter().filter(|&x| *x & 1 == 0);
-        assert_eq!(it.next_back().unwrap(), &6);
-        assert_eq!(it.next_back().unwrap(), &4);
-        assert_eq!(it.next().unwrap(), &2);
-        assert_eq!(it.next_back(), None);
-    }
-
-    #[test]
-    fn test_double_ended_filter_map() {
-        let xs = [1, 2, 3, 4, 5, 6];
-        let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
-        assert_eq!(it.next_back().unwrap(), 12);
-        assert_eq!(it.next_back().unwrap(), 8);
-        assert_eq!(it.next().unwrap(), 4);
-        assert_eq!(it.next_back(), None);
-    }
-
-    #[test]
-    fn test_double_ended_chain() {
-        let xs = [1, 2, 3, 4, 5];
-        let ys = box [7, 9, 11];
-        let mut it = xs.iter().chain(ys.iter()).rev();
-        assert_eq!(it.next().unwrap(), &11)
-        assert_eq!(it.next().unwrap(), &9)
-        assert_eq!(it.next_back().unwrap(), &1)
-        assert_eq!(it.next_back().unwrap(), &2)
-        assert_eq!(it.next_back().unwrap(), &3)
-        assert_eq!(it.next_back().unwrap(), &4)
-        assert_eq!(it.next_back().unwrap(), &5)
-        assert_eq!(it.next_back().unwrap(), &7)
-        assert_eq!(it.next_back(), None)
-    }
-
-    #[test]
-    fn test_rposition() {
-        fn f(xy: &(int, char)) -> bool { let (_x, y) = *xy; y == 'b' }
-        fn g(xy: &(int, char)) -> bool { let (_x, y) = *xy; y == 'd' }
-        let v = box [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
-
-        assert_eq!(v.iter().rposition(f), Some(3u));
-        assert!(v.iter().rposition(g).is_none());
-    }
-
-    #[test]
-    #[should_fail]
-    fn test_rposition_fail() {
-        let v = [(box 0, @0), (box 0, @0), (box 0, @0), (box 0, @0)];
-        let mut i = 0;
-        v.iter().rposition(|_elt| {
-            if i == 2 {
-                fail!()
-            }
-            i += 1;
-            false
-        });
-    }
-
-
-    #[cfg(test)]
-    fn check_randacc_iter<A: Eq, T: Clone + RandomAccessIterator<A>>(a: T, len: uint)
-    {
-        let mut b = a.clone();
-        assert_eq!(len, b.indexable());
-        let mut n = 0;
-        for (i, elt) in a.enumerate() {
-            assert!(Some(elt) == b.idx(i));
-            n += 1;
-        }
-        assert_eq!(n, len);
-        assert!(None == b.idx(n));
-        // call recursively to check after picking off an element
-        if len > 0 {
-            b.next();
-            check_randacc_iter(b, len-1);
-        }
-    }
-
-
-    #[test]
-    fn test_double_ended_flat_map() {
-        let u = [0u,1];
-        let v = [5,6,7,8];
-        let mut it = u.iter().flat_map(|x| v.slice(*x, v.len()).iter());
-        assert_eq!(it.next_back().unwrap(), &8);
-        assert_eq!(it.next().unwrap(),      &5);
-        assert_eq!(it.next_back().unwrap(), &7);
-        assert_eq!(it.next_back().unwrap(), &6);
-        assert_eq!(it.next_back().unwrap(), &8);
-        assert_eq!(it.next().unwrap(),      &6);
-        assert_eq!(it.next_back().unwrap(), &7);
-        assert_eq!(it.next_back(), None);
-        assert_eq!(it.next(),      None);
-        assert_eq!(it.next_back(), None);
-    }
-
-    #[test]
-    fn test_random_access_chain() {
-        let xs = [1, 2, 3, 4, 5];
-        let ys = box [7, 9, 11];
-        let mut it = xs.iter().chain(ys.iter());
-        assert_eq!(it.idx(0).unwrap(), &1);
-        assert_eq!(it.idx(5).unwrap(), &7);
-        assert_eq!(it.idx(7).unwrap(), &11);
-        assert!(it.idx(8).is_none());
-
-        it.next();
-        it.next();
-        it.next_back();
-
-        assert_eq!(it.idx(0).unwrap(), &3);
-        assert_eq!(it.idx(4).unwrap(), &9);
-        assert!(it.idx(6).is_none());
-
-        check_randacc_iter(it, xs.len() + ys.len() - 3);
-    }
-
-    #[test]
-    fn test_random_access_enumerate() {
-        let xs = [1, 2, 3, 4, 5];
-        check_randacc_iter(xs.iter().enumerate(), xs.len());
-    }
-
-    #[test]
-    fn test_random_access_rev() {
-        let xs = [1, 2, 3, 4, 5];
-        check_randacc_iter(xs.iter().rev(), xs.len());
-        let mut it = xs.iter().rev();
-        it.next();
-        it.next_back();
-        it.next();
-        check_randacc_iter(it, xs.len() - 3);
-    }
-
-    #[test]
-    fn test_random_access_zip() {
-        let xs = [1, 2, 3, 4, 5];
-        let ys = [7, 9, 11];
-        check_randacc_iter(xs.iter().zip(ys.iter()), cmp::min(xs.len(), ys.len()));
-    }
-
-    #[test]
-    fn test_random_access_take() {
-        let xs = [1, 2, 3, 4, 5];
-        let empty: &[int] = [];
-        check_randacc_iter(xs.iter().take(3), 3);
-        check_randacc_iter(xs.iter().take(20), xs.len());
-        check_randacc_iter(xs.iter().take(0), 0);
-        check_randacc_iter(empty.iter().take(2), 0);
-    }
-
-    #[test]
-    fn test_random_access_skip() {
-        let xs = [1, 2, 3, 4, 5];
-        let empty: &[int] = [];
-        check_randacc_iter(xs.iter().skip(2), xs.len() - 2);
-        check_randacc_iter(empty.iter().skip(2), 0);
-    }
-
-    #[test]
-    fn test_random_access_inspect() {
-        let xs = [1, 2, 3, 4, 5];
-
-        // test .map and .inspect that don't implement Clone
-        let mut it = xs.iter().inspect(|_| {});
-        assert_eq!(xs.len(), it.indexable());
-        for (i, elt) in xs.iter().enumerate() {
-            assert_eq!(Some(elt), it.idx(i));
-        }
-
-    }
-
-    #[test]
-    fn test_random_access_map() {
-        let xs = [1, 2, 3, 4, 5];
-
-        let mut it = xs.iter().map(|x| *x);
-        assert_eq!(xs.len(), it.indexable());
-        for (i, elt) in xs.iter().enumerate() {
-            assert_eq!(Some(*elt), it.idx(i));
-        }
-    }
-
-    #[test]
-    fn test_random_access_cycle() {
-        let xs = [1, 2, 3, 4, 5];
-        let empty: &[int] = [];
-        check_randacc_iter(xs.iter().cycle().take(27), 27);
-        check_randacc_iter(empty.iter().cycle(), 0);
-    }
-
-    #[test]
-    fn test_double_ended_range() {
-        assert_eq!(range(11i, 14).rev().collect::<~[int]>(), box [13i, 12, 11]);
-        for _ in range(10i, 0).rev() {
-            fail!("unreachable");
-        }
-
-        assert_eq!(range(11u, 14).rev().collect::<~[uint]>(), box [13u, 12, 11]);
-        for _ in range(10u, 0).rev() {
-            fail!("unreachable");
-        }
-    }
-
-    #[test]
-    fn test_range() {
-        /// A mock type to check Range when ToPrimitive returns None
-        struct Foo;
-
-        impl ToPrimitive for Foo {
-            fn to_i64(&self) -> Option<i64> { None }
-            fn to_u64(&self) -> Option<u64> { None }
-        }
-
-        impl Add<Foo, Foo> for Foo {
-            fn add(&self, _: &Foo) -> Foo {
-                Foo
-            }
-        }
-
-        impl Eq for Foo {
-            fn eq(&self, _: &Foo) -> bool {
-                true
-            }
-        }
-
-        impl Ord for Foo {
-            fn lt(&self, _: &Foo) -> bool {
-                false
-            }
-        }
-
-        impl Clone for Foo {
-            fn clone(&self) -> Foo {
-                Foo
-            }
-        }
-
-        impl Mul<Foo, Foo> for Foo {
-            fn mul(&self, _: &Foo) -> Foo {
-                Foo
-            }
-        }
-
-        impl num::One for Foo {
-            fn one() -> Foo {
-                Foo
-            }
-        }
-
-        assert_eq!(range(0i, 5).collect::<~[int]>(), box [0i, 1, 2, 3, 4]);
-        assert_eq!(range(-10i, -1).collect::<~[int]>(), box [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
-        assert_eq!(range(0i, 5).rev().collect::<~[int]>(), box [4, 3, 2, 1, 0]);
-        assert_eq!(range(200, -5).collect::<~[int]>(), box []);
-        assert_eq!(range(200, -5).rev().collect::<~[int]>(), box []);
-        assert_eq!(range(200, 200).collect::<~[int]>(), box []);
-        assert_eq!(range(200, 200).rev().collect::<~[int]>(), box []);
-
-        assert_eq!(range(0i, 100).size_hint(), (100, Some(100)));
-        // this test is only meaningful when sizeof uint < sizeof u64
-        assert_eq!(range(uint::MAX - 1, uint::MAX).size_hint(), (1, Some(1)));
-        assert_eq!(range(-10i, -1).size_hint(), (9, Some(9)));
-        assert_eq!(range(Foo, Foo).size_hint(), (0, None));
-    }
-
-    #[test]
-    fn test_range_inclusive() {
-        assert_eq!(range_inclusive(0i, 5).collect::<~[int]>(), box [0i, 1, 2, 3, 4, 5]);
-        assert_eq!(range_inclusive(0i, 5).rev().collect::<~[int]>(), box [5i, 4, 3, 2, 1, 0]);
-        assert_eq!(range_inclusive(200, -5).collect::<~[int]>(), box []);
-        assert_eq!(range_inclusive(200, -5).rev().collect::<~[int]>(), box []);
-        assert_eq!(range_inclusive(200, 200).collect::<~[int]>(), box [200]);
-        assert_eq!(range_inclusive(200, 200).rev().collect::<~[int]>(), box [200]);
-    }
-
-    #[test]
-    fn test_range_step() {
-        assert_eq!(range_step(0i, 20, 5).collect::<~[int]>(), box [0, 5, 10, 15]);
-        assert_eq!(range_step(20i, 0, -5).collect::<~[int]>(), box [20, 15, 10, 5]);
-        assert_eq!(range_step(20i, 0, -6).collect::<~[int]>(), box [20, 14, 8, 2]);
-        assert_eq!(range_step(200u8, 255, 50).collect::<~[u8]>(), box [200u8, 250]);
-        assert_eq!(range_step(200, -5, 1).collect::<~[int]>(), box []);
-        assert_eq!(range_step(200, 200, 1).collect::<~[int]>(), box []);
-    }
-
-    #[test]
-    fn test_range_step_inclusive() {
-        assert_eq!(range_step_inclusive(0i, 20, 5).collect::<~[int]>(), box [0, 5, 10, 15, 20]);
-        assert_eq!(range_step_inclusive(20i, 0, -5).collect::<~[int]>(), box [20, 15, 10, 5, 0]);
-        assert_eq!(range_step_inclusive(20i, 0, -6).collect::<~[int]>(), box [20, 14, 8, 2]);
-        assert_eq!(range_step_inclusive(200u8, 255, 50).collect::<~[u8]>(), box [200u8, 250]);
-        assert_eq!(range_step_inclusive(200, -5, 1).collect::<~[int]>(), box []);
-        assert_eq!(range_step_inclusive(200, 200, 1).collect::<~[int]>(), box [200]);
-    }
-
-    #[test]
-    fn test_reverse() {
-        let mut ys = [1, 2, 3, 4, 5];
-        ys.mut_iter().reverse_();
-        assert!(ys == [5, 4, 3, 2, 1]);
-    }
-
-    #[test]
-    fn test_peekable_is_empty() {
-        let a = [1];
-        let mut it = a.iter().peekable();
-        assert!( !it.is_empty() );
-        it.next();
-        assert!( it.is_empty() );
-    }
-
-    #[test]
-    fn test_min_max() {
-        let v: [int, ..0] = [];
-        assert_eq!(v.iter().min_max(), NoElements);
-
-        let v = [1i];
-        assert!(v.iter().min_max() == OneElement(&1));
-
-        let v = [1i, 2, 3, 4, 5];
-        assert!(v.iter().min_max() == MinMax(&1, &5));
-
-        let v = [1i, 2, 3, 4, 5, 6];
-        assert!(v.iter().min_max() == MinMax(&1, &6));
-
-        let v = [1i, 1, 1, 1];
-        assert!(v.iter().min_max() == MinMax(&1, &1));
-    }
-
-    #[test]
-    fn test_MinMaxResult() {
-        let r: MinMaxResult<int> = NoElements;
-        assert_eq!(r.into_option(), None)
-
-        let r = OneElement(1);
-        assert_eq!(r.into_option(), Some((1,1)));
-
-        let r = MinMax(1,2);
-        assert_eq!(r.into_option(), Some((1,2)));
-    }
-}