Auto merge of #23293 - tbu-:pr_additive_multiplicative, r=alexcrichton
Previously it could not be implemented for types outside `libcore/iter.rs` due to coherence issues.
This commit is contained in:
commit
dd6c4a8f15
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@ -85,7 +85,6 @@ use core::clone::Clone;
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use core::cmp::Ordering::{self, Greater, Less};
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use core::cmp::{self, Ord, PartialEq};
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use core::iter::Iterator;
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use core::iter::MultiplicativeIterator;
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use core::marker::Sized;
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use core::mem::size_of;
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use core::mem;
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@ -1182,7 +1181,7 @@ impl Iterator for ElementSwaps {
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#[inline]
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fn size_hint(&self) -> (usize, Option<usize>) {
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// For a vector of size n, there are exactly n! permutations.
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let n = (2..self.sdir.len() + 1).product();
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let n: usize = (2..self.sdir.len() + 1).product();
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(n - self.swaps_made, Some(n - self.swaps_made))
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}
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}
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@ -53,7 +53,6 @@ use self::RecompositionState::*;
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use self::DecompositionType::*;
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use core::clone::Clone;
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use core::iter::AdditiveIterator;
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use core::iter::{Iterator, Extend};
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use core::option::Option::{self, Some, None};
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use core::result::Result;
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@ -116,7 +115,7 @@ impl<S: AsRef<str>> SliceConcatExt<str, String> for [S] {
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// this is wrong without the guarantee that `self` is non-empty
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// `len` calculation may overflow but push_str but will check boundaries
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let len = sep.len() * (self.len() - 1)
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+ self.iter().map(|s| s.as_ref().len()).sum();
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+ self.iter().map(|s| s.as_ref().len()).sum::<usize>();
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let mut result = String::with_capacity(len);
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let mut first = true;
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@ -9,7 +9,6 @@
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// except according to those terms.
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use std::cmp::Ordering::{Equal, Greater, Less};
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use std::iter::AdditiveIterator;
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use std::str::{Utf8Error, from_utf8};
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#[test]
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@ -65,7 +65,7 @@ use default::Default;
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use marker;
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use mem;
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use num::{Int, Zero, One};
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use ops::{self, Add, Sub, FnMut, RangeFrom};
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use ops::{self, Add, Sub, FnMut, Mul, RangeFrom};
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use option::Option::{self, Some, None};
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use marker::Sized;
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use usize;
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@ -489,10 +489,9 @@ pub trait Iterator {
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///
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/// ```
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/// # #![feature(core)]
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/// use std::iter::AdditiveIterator;
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///
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/// let a = [1, 4, 2, 3, 8, 9, 6];
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/// let sum = a.iter()
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/// let sum: i32 = a.iter()
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/// .map(|x| *x)
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/// .inspect(|&x| println!("filtering {}", x))
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/// .filter(|&x| x % 2 == 0)
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@ -1022,6 +1021,47 @@ pub trait Iterator {
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}
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}
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}
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/// Iterates over the entire iterator, summing up all the elements
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///
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/// # Examples
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///
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/// ```
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/// # #![feature(core)]
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///
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/// let a = [1, 2, 3, 4, 5];
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/// let mut it = a.iter().cloned();
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/// assert!(it.sum::<i32>() == 15);
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/// ```
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#[unstable(feature="core")]
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fn sum<S=<Self as Iterator>::Item>(self) -> S where
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S: Add<Self::Item, Output=S> + Zero,
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Self: Sized,
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{
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self.fold(Zero::zero(), |s, e| s + e)
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}
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/// Iterates over the entire iterator, multiplying all the elements
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///
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/// # Examples
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///
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/// ```
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/// # #![feature(core)]
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///
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/// fn factorial(n: u32) -> u32 {
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/// (1..).take_while(|&i| i <= n).product()
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/// }
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/// assert!(factorial(0) == 1);
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/// assert!(factorial(1) == 1);
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/// assert!(factorial(5) == 120);
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/// ```
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#[unstable(feature="core")]
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fn product<P=<Self as Iterator>::Item>(self) -> P where
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P: Mul<Self::Item, Output=P> + One,
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Self: Sized,
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{
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self.fold(One::one(), |p, e| p * e)
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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@ -1222,95 +1262,6 @@ impl<I> RandomAccessIterator for Rev<I>
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}
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}
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/// A trait for iterators over elements which can be added together
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#[unstable(feature = "core",
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reason = "needs to be re-evaluated as part of numerics reform")]
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pub trait AdditiveIterator<A> {
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/// Iterates over the entire iterator, summing up all the elements
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///
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/// # Examples
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///
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/// ```
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/// # #![feature(core)]
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/// use std::iter::AdditiveIterator;
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///
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/// let a = [1, 2, 3, 4, 5];
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/// let mut it = a.iter().cloned();
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/// assert!(it.sum() == 15);
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/// ```
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fn sum(self) -> A;
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}
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macro_rules! impl_additive {
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($A:ty, $init:expr) => {
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#[unstable(feature = "core", reason = "trait is experimental")]
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impl<T: Iterator<Item=$A>> AdditiveIterator<$A> for T {
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#[inline]
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fn sum(self) -> $A {
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self.fold($init, |acc, x| acc + x)
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}
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}
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};
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}
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impl_additive! { i8, 0 }
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impl_additive! { i16, 0 }
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impl_additive! { i32, 0 }
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impl_additive! { i64, 0 }
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impl_additive! { isize, 0 }
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impl_additive! { u8, 0 }
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impl_additive! { u16, 0 }
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impl_additive! { u32, 0 }
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impl_additive! { u64, 0 }
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impl_additive! { usize, 0 }
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impl_additive! { f32, 0.0 }
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impl_additive! { f64, 0.0 }
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/// A trait for iterators over elements which can be multiplied together.
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#[unstable(feature = "core",
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reason = "needs to be re-evaluated as part of numerics reform")]
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pub trait MultiplicativeIterator<A> {
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/// Iterates over the entire iterator, multiplying all the elements
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///
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/// # Examples
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///
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/// ```
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/// # #![feature(core)]
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/// use std::iter::MultiplicativeIterator;
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///
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/// fn factorial(n: usize) -> usize {
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/// (1..).take_while(|&i| i <= n).product()
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/// }
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/// assert!(factorial(0) == 1);
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/// assert!(factorial(1) == 1);
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/// assert!(factorial(5) == 120);
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/// ```
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fn product(self) -> A;
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}
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macro_rules! impl_multiplicative {
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($A:ty, $init:expr) => {
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#[unstable(feature = "core", reason = "trait is experimental")]
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impl<T: Iterator<Item=$A>> MultiplicativeIterator<$A> for T {
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#[inline]
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fn product(self) -> $A {
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self.fold($init, |acc, x| acc * x)
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}
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}
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};
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}
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impl_multiplicative! { i8, 1 }
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impl_multiplicative! { i16, 1 }
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impl_multiplicative! { i32, 1 }
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impl_multiplicative! { i64, 1 }
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impl_multiplicative! { isize, 1 }
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impl_multiplicative! { u8, 1 }
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impl_multiplicative! { u16, 1 }
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impl_multiplicative! { u32, 1 }
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impl_multiplicative! { u64, 1 }
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impl_multiplicative! { usize, 1 }
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impl_multiplicative! { f32, 1.0 }
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impl_multiplicative! { f64, 1.0 }
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/// `MinMaxResult` is an enum returned by `min_max`. See `Iterator::min_max` for
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/// more detail.
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#[derive(Clone, PartialEq, Debug)]
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@ -86,6 +86,20 @@ macro_rules! zero_one_impl {
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}
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zero_one_impl! { u8 u16 u32 u64 usize i8 i16 i32 i64 isize }
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macro_rules! zero_one_impl_float {
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($($t:ty)*) => ($(
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impl Zero for $t {
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#[inline]
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fn zero() -> $t { 0.0 }
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}
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impl One for $t {
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#[inline]
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fn one() -> $t { 1.0 }
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}
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)*)
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}
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zero_one_impl_float! { f32 f64 }
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/// A built-in signed or unsigned integer.
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#[stable(feature = "rust1", since = "1.0.0")]
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#[deprecated(since = "1.0.0",
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@ -329,17 +329,17 @@ fn test_iterator_len() {
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#[test]
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fn test_iterator_sum() {
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let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
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assert_eq!(v[..4].iter().cloned().sum(), 6);
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assert_eq!(v.iter().cloned().sum(), 55);
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assert_eq!(v[..0].iter().cloned().sum(), 0);
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assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
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assert_eq!(v.iter().cloned().sum::<i32>(), 55);
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assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
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}
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#[test]
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fn test_iterator_product() {
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let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
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assert_eq!(v[..4].iter().cloned().product(), 0);
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assert_eq!(v[1..5].iter().cloned().product(), 24);
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assert_eq!(v[..0].iter().cloned().product(), 1);
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assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
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assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
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assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
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}
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#[test]
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@ -26,7 +26,7 @@ use middle::ty::*;
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use middle::ty;
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use std::cmp::Ordering;
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use std::fmt;
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use std::iter::{range_inclusive, AdditiveIterator, FromIterator, IntoIterator, repeat};
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use std::iter::{range_inclusive, FromIterator, IntoIterator, repeat};
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use std::slice;
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use syntax::ast::{self, DUMMY_NODE_ID, NodeId, Pat};
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use syntax::ast_util;
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@ -76,7 +76,7 @@ impl<'a> fmt::Debug for Matrix<'a> {
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pretty_printed_matrix.iter().map(|row| row[col].len()).max().unwrap_or(0)
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}).collect();
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let total_width = column_widths.iter().cloned().sum() + column_count * 3 + 1;
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let total_width = column_widths.iter().cloned().sum::<usize>() + column_count * 3 + 1;
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let br = repeat('+').take(total_width).collect::<String>();
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try!(write!(f, "{}\n", br));
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for row in pretty_printed_matrix {
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@ -220,7 +220,6 @@ use util::ppaux::{Repr, vec_map_to_string};
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use std;
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use std::cmp::Ordering;
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use std::iter::AdditiveIterator;
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use std::rc::Rc;
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use syntax::ast;
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use syntax::ast::{DUMMY_NODE_ID, NodeId};
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@ -61,7 +61,7 @@ use rscope::{self, UnelidableRscope, RegionScope, ElidableRscope,
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use util::common::{ErrorReported, FN_OUTPUT_NAME};
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use util::ppaux::{self, Repr, UserString};
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use std::iter::{repeat, AdditiveIterator};
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use std::iter::repeat;
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use std::rc::Rc;
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use std::slice;
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use syntax::{abi, ast, ast_util};
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@ -517,7 +517,8 @@ fn find_implied_output_region(input_tys: &[Ty], input_pats: Vec<String>)
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lifetimes_for_params.push((input_pat, accumulator.len()));
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}
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let implied_output_region = if lifetimes_for_params.iter().map(|&(_, n)| n).sum() == 1 {
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let implied_output_region =
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if lifetimes_for_params.iter().map(|&(_, n)| n).sum::<usize>() == 1 {
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assert!(possible_implied_output_region.is_some());
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possible_implied_output_region
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} else {
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@ -15,8 +15,7 @@ use cmp::{Ordering, Eq, Ord, PartialEq, PartialOrd};
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use fmt;
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use hash;
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use old_io::Writer;
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use iter::{AdditiveIterator, Extend};
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use iter::{Iterator, Map};
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use iter::{Extend, Iterator, Map};
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use marker::Sized;
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use option::Option::{self, Some, None};
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use result::Result::{self, Ok, Err};
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@ -351,7 +350,7 @@ impl Path {
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Some(vec![SEP_BYTE])
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} else {
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let n = if is_abs { comps.len() } else { comps.len() - 1} +
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comps.iter().map(|v| v.len()).sum();
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comps.iter().map(|v| v.len()).sum::<usize>();
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let mut v = Vec::with_capacity(n);
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let mut it = comps.into_iter();
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if !is_abs {
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@ -20,8 +20,7 @@ use cmp::{Ordering, Eq, Ord, PartialEq, PartialOrd};
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use fmt;
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use hash;
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use old_io::Writer;
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use iter::{AdditiveIterator, Extend};
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use iter::{Iterator, Map, repeat};
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use iter::{Extend, Iterator, Map, repeat};
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use mem;
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use option::Option::{self, Some, None};
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use result::Result::{self, Ok, Err};
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@ -785,7 +784,7 @@ impl Path {
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let prefix_ = &s[..prefix_len(prefix)];
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let n = prefix_.len() +
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if is_abs { comps.len() } else { comps.len() - 1} +
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comps.iter().map(|v| v.len()).sum();
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comps.iter().map(|v| v.len()).sum::<usize>();
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let mut s = String::with_capacity(n);
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match prefix {
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Some(DiskPrefix) => {
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@ -20,7 +20,7 @@ use core::prelude::*;
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use core::char;
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use core::cmp;
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use core::iter::{Filter, AdditiveIterator};
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use core::iter::Filter;
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use core::mem;
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use core::slice;
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use core::str::Split;
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@ -13,7 +13,6 @@
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use std::io::prelude::*;
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use std::io::BufReader;
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use std::iter;
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use std::iter::AdditiveIterator;
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use std::path::{Path, PathBuf};
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pub struct BookItem {
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@ -151,7 +150,7 @@ pub fn parse_summary(input: &mut Read, src: &Path) -> Result<Book, Vec<String>>
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'\t' => 4,
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_ => unreachable!()
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}
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}).sum() / 4 + 1;
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}).sum::<usize>() / 4 + 1;
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if level > stack.len() + 1 {
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errors.push(format!("section '{}' is indented too deeply; \
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@ -43,7 +43,7 @@
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#![allow(non_snake_case)]
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#![feature(unboxed_closures, core, os)]
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use std::iter::{repeat, AdditiveIterator};
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use std::iter::repeat;
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use std::thread;
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use std::mem;
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use std::num::Float;
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@ -12,8 +12,7 @@
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#![feature(core)]
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use std::iter::AdditiveIterator;
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fn main() {
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let x: [u64; 3] = [1, 2, 3];
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assert_eq!(6, (0..3).map(|i| x[i]).sum());
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assert_eq!(6, (0..3).map(|i| x[i]).sum::<u64>());
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}
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@ -15,10 +15,8 @@
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#![feature(core)]
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use std::iter::AdditiveIterator;
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fn square_sum(v: &[i64]) -> i64 {
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let sum = v.iter().cloned().sum();
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let sum: i64 = v.iter().cloned().sum();
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sum * sum
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}
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