auto merge of #13648 : gereeter/rust/removed-rev, r=alexcrichton

In the process, `Splits` got changed to be more like `CharSplits` in `str` to present the DEI interface.

Note that `treemap` still has a `rev_iter` function because it seems like it would be a significant interface change to expose a DEI - the iterator would have to gain an extra pointer, the completion checks would be more complicated, and it isn't easy to check that such an implementation is correct due to the use of unsafety to subvert the aliasing properties of `&mut`.

This fixes #9391.

Author: bors

src/doc/guide-container.md

@@ -120,12 +120,13 @@ differently.
 Containers implement iteration over the contained elements by returning an
 iterator object. For example, vector slices several iterators available:
 
-* `iter()` and `rev_iter()`, for immutable references to the elements
-* `mut_iter()` and `mut_rev_iter()`, for mutable references to the elements
-* `move_iter()` and `move_rev_iter()`, to move the elements out by-value
+* `iter()` for immutable references to the elements
+* `mut_iter()` for mutable references to the elements
+* `move_iter()` to move the elements out by-value
 
 A typical mutable container will implement at least `iter()`, `mut_iter()` and
-`move_iter()` along with the reverse variants if it maintains an order.
+`move_iter()`. If it maintains an order, the returned iterators will be
+`DoubleEndedIterator`s, which are described below.
 
 ### Freezing
 
@@ -265,7 +266,7 @@ Iterators offer generic conversion to containers with the `collect` adaptor:
 
 ~~~
 let xs = [0, 1, 1, 2, 3, 5, 8];
-let ys = xs.rev_iter().skip(1).map(|&x| x * 2).collect::<~[int]>();
+let ys = xs.iter().rev().skip(1).map(|&x| x * 2).collect::<~[int]>();
 assert_eq!(ys, ~[10, 6, 4, 2, 2, 0]);
 ~~~
 
@@ -358,9 +359,6 @@ for &x in it.rev() {
 }
 ~~~
 
-The `rev_iter` and `mut_rev_iter` methods on vectors just return an inverted
-version of the standard immutable and mutable vector iterators.
-
 The `chain`, `map`, `filter`, `filter_map` and `inspect` adaptors are
 `DoubleEndedIterator` implementations if the underlying iterators are.
 

src/libcollections/bitv.rs

@@ -425,6 +425,7 @@ impl Bitv {
     }
 
     #[inline]
+    #[deprecated = "replaced by .iter().rev()"]
     pub fn rev_iter<'a>(&'a self) -> Rev<Bits<'a>> {
         self.iter().rev()
     }

src/libcollections/dlist.rs

@@ -1,4 +1,4 @@
-// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -370,8 +370,8 @@ impl<T> DList<T> {
         Items{nelem: self.len(), head: &self.list_head, tail: self.list_tail}
     }
 
-    /// Provide a reverse iterator
     #[inline]
+    #[deprecated = "replaced by .iter().rev()"]
     pub fn rev_iter<'a>(&'a self) -> Rev<Items<'a, T>> {
         self.iter().rev()
     }
@@ -390,8 +390,9 @@ impl<T> DList<T> {
             list: self
         }
     }
-    /// Provide a reverse iterator with mutable references
+
     #[inline]
+    #[deprecated = "replaced by .mut_iter().rev()"]
     pub fn mut_rev_iter<'a>(&'a mut self) -> Rev<MutItems<'a, T>> {
         self.mut_iter().rev()
     }
@@ -403,8 +404,8 @@ impl<T> DList<T> {
         MoveItems{list: self}
     }
 
-    /// Consume the list into an iterator yielding elements by value, in reverse
     #[inline]
+    #[deprecated = "replaced by .move_iter().rev()"]
     pub fn move_rev_iter(self) -> Rev<MoveItems<T>> {
         self.move_iter().rev()
     }
@@ -849,13 +850,13 @@ mod tests {
     #[test]
     fn test_rev_iter() {
         let m = generate_test();
-        for (i, elt) in m.rev_iter().enumerate() {
+        for (i, elt) in m.iter().rev().enumerate() {
             assert_eq!((6 - i) as int, *elt);
         }
         let mut n = DList::new();
-        assert_eq!(n.rev_iter().next(), None);
+        assert_eq!(n.iter().rev().next(), None);
         n.push_front(4);
-        let mut it = n.rev_iter();
+        let mut it = n.iter().rev();
         assert_eq!(it.size_hint(), (1, Some(1)));
         assert_eq!(it.next().unwrap(), &4);
         assert_eq!(it.size_hint(), (0, Some(0)));
@@ -958,13 +959,13 @@ mod tests {
     #[test]
     fn test_mut_rev_iter() {
         let mut m = generate_test();
-        for (i, elt) in m.mut_rev_iter().enumerate() {
+        for (i, elt) in m.mut_iter().rev().enumerate() {
             assert_eq!((6-i) as int, *elt);
         }
         let mut n = DList::new();
-        assert!(n.mut_rev_iter().next().is_none());
+        assert!(n.mut_iter().rev().next().is_none());
         n.push_front(4);
-        let mut it = n.mut_rev_iter();
+        let mut it = n.mut_iter().rev();
         assert!(it.next().is_some());
         assert!(it.next().is_none());
     }
@@ -1164,15 +1165,15 @@ mod tests {
         let v = &[0, ..128];
         let m: DList<int> = v.iter().map(|&x|x).collect();
         b.iter(|| {
-            assert!(m.rev_iter().len() == 128);
+            assert!(m.iter().rev().len() == 128);
         })
     }
     #[bench]
     fn bench_iter_mut_rev(b: &mut test::Bencher) {
         let v = &[0, ..128];
         let mut m: DList<int> = v.iter().map(|&x|x).collect();
         b.iter(|| {
-            assert!(m.mut_rev_iter().len() == 128);
+            assert!(m.mut_iter().rev().len() == 128);
         })
     }
 }

src/libcollections/priority_queue.rs

@@ -1,4 +1,4 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// 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.
 //
@@ -382,7 +382,7 @@ mod tests {
     fn test_from_iter() {
         let xs = vec!(9u, 8, 7, 6, 5, 4, 3, 2, 1);
 
-        let mut q: PriorityQueue<uint> = xs.as_slice().rev_iter().map(|&x| x).collect();
+        let mut q: PriorityQueue<uint> = xs.as_slice().iter().rev().map(|&x| x).collect();
 
         for &x in xs.iter() {
             assert_eq!(q.pop(), x);

src/libcollections/ringbuf.rs

@@ -1,4 +1,4 @@
-// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -190,7 +190,7 @@ impl<T> RingBuf<T> {
         Items{index: 0, rindex: self.nelts, lo: self.lo, elts: self.elts.as_slice()}
     }
 
-    /// Back-to-front iterator.
+    #[deprecated = "replaced by .iter().rev()"]
     pub fn rev_iter<'a>(&'a self) -> Rev<Items<'a, T>> {
         self.iter().rev()
     }
@@ -221,7 +221,7 @@ impl<T> RingBuf<T> {
         }
     }
 
-    /// Back-to-front iterator which returns mutable values.
+    #[deprecated = "replaced by .mut_iter().rev()"]
     pub fn mut_rev_iter<'a>(&'a mut self) -> Rev<MutItems<'a, T>> {
         self.mut_iter().rev()
     }
@@ -702,31 +702,31 @@ mod tests {
     #[test]
     fn test_rev_iter() {
         let mut d = RingBuf::new();
-        assert_eq!(d.rev_iter().next(), None);
+        assert_eq!(d.iter().rev().next(), None);
 
         for i in range(0, 5) {
             d.push_back(i);
         }
-        assert_eq!(d.rev_iter().collect::<Vec<&int>>().as_slice(), &[&4,&3,&2,&1,&0]);
+        assert_eq!(d.iter().rev().collect::<Vec<&int>>().as_slice(), &[&4,&3,&2,&1,&0]);
 
         for i in range(6, 9) {
             d.push_front(i);
         }
-        assert_eq!(d.rev_iter().collect::<Vec<&int>>().as_slice(), &[&4,&3,&2,&1,&0,&6,&7,&8]);
+        assert_eq!(d.iter().rev().collect::<Vec<&int>>().as_slice(), &[&4,&3,&2,&1,&0,&6,&7,&8]);
     }
 
     #[test]
     fn test_mut_rev_iter_wrap() {
         let mut d = RingBuf::with_capacity(3);
-        assert!(d.mut_rev_iter().next().is_none());
+        assert!(d.mut_iter().rev().next().is_none());
 
         d.push_back(1);
         d.push_back(2);
         d.push_back(3);
         assert_eq!(d.pop_front(), Some(1));
         d.push_back(4);
 
-        assert_eq!(d.mut_rev_iter().map(|x| *x).collect::<Vec<int>>(),
+        assert_eq!(d.mut_iter().rev().map(|x| *x).collect::<Vec<int>>(),
                    vec!(4, 3, 2));
     }
 
@@ -756,19 +756,19 @@ mod tests {
     #[test]
     fn test_mut_rev_iter() {
         let mut d = RingBuf::new();
-        assert!(d.mut_rev_iter().next().is_none());
+        assert!(d.mut_iter().rev().next().is_none());
 
         for i in range(0u, 3) {
             d.push_front(i);
         }
 
-        for (i, elt) in d.mut_rev_iter().enumerate() {
+        for (i, elt) in d.mut_iter().rev().enumerate() {
             assert_eq!(*elt, i);
             *elt = i;
         }
 
         {
-            let mut it = d.mut_rev_iter();
+            let mut it = d.mut_iter().rev();
             assert_eq!(*it.next().unwrap(), 0);
             assert_eq!(*it.next().unwrap(), 1);
             assert_eq!(*it.next().unwrap(), 2);

src/libcollections/smallintmap.rs

@@ -1,4 +1,4 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -142,16 +142,13 @@ impl<V> SmallIntMap<V> {
         }
     }
 
-    /// An iterator visiting all key-value pairs in descending order by the keys.
-    /// Iterator element type is (uint, &'r V)
-    pub fn rev_iter<'r>(&'r self) -> RevEntries<'r, V> {
+    #[deprecated = "replaced by .iter().rev()"]
+    pub fn rev_iter<'r>(&'r self) -> Rev<Entries<'r, V>> {
         self.iter().rev()
     }
 
-    /// An iterator visiting all key-value pairs in descending order by the keys,
-    /// with mutable references to the values
-    /// Iterator element type is (uint, &'r mut V)
-    pub fn mut_rev_iter<'r>(&'r mut self) -> RevMutEntries <'r, V> {
+    #[deprecated = "replaced by .mut_iter().rev()"]
+    pub fn mut_rev_iter<'r>(&'r mut self) -> Rev<MutEntries<'r, V>> {
         self.mut_iter().rev()
     }
 
@@ -246,6 +243,7 @@ pub struct Entries<'a, T> {
 
 iterator!(impl Entries -> (uint, &'a T), get_ref)
 double_ended_iterator!(impl Entries -> (uint, &'a T), get_ref)
+#[deprecated = "replaced by Rev<Entries<'a, T>>"]
 pub type RevEntries<'a, T> = Rev<Entries<'a, T>>;
 
 pub struct MutEntries<'a, T> {
@@ -256,6 +254,7 @@ pub struct MutEntries<'a, T> {
 
 iterator!(impl MutEntries -> (uint, &'a mut T), get_mut_ref)
 double_ended_iterator!(impl MutEntries -> (uint, &'a mut T), get_mut_ref)
+#[deprecated = "replaced by Rev<MutEntries<'a, T>"]
 pub type RevMutEntries<'a, T> = Rev<MutEntries<'a, T>>;
 
 #[cfg(test)]
@@ -387,9 +386,9 @@ mod test_map {
         assert!(m.insert(10, 11));
 
         assert_eq!(m.iter().size_hint(), (0, Some(11)));
-        assert_eq!(m.rev_iter().size_hint(), (0, Some(11)));
+        assert_eq!(m.iter().rev().size_hint(), (0, Some(11)));
         assert_eq!(m.mut_iter().size_hint(), (0, Some(11)));
-        assert_eq!(m.mut_rev_iter().size_hint(), (0, Some(11)));
+        assert_eq!(m.mut_iter().rev().size_hint(), (0, Some(11)));
     }
 
     #[test]
@@ -425,7 +424,7 @@ mod test_map {
         assert!(m.insert(6, 10));
         assert!(m.insert(10, 11));
 
-        let mut it = m.rev_iter();
+        let mut it = m.iter().rev();
         assert_eq!(it.next().unwrap(), (10, &11));
         assert_eq!(it.next().unwrap(), (6, &10));
         assert_eq!(it.next().unwrap(), (3, &5));
@@ -444,7 +443,7 @@ mod test_map {
         assert!(m.insert(6, 10));
         assert!(m.insert(10, 11));
 
-        for (k, v) in m.mut_rev_iter() {
+        for (k, v) in m.mut_iter().rev() {
             *v += k as int;
         }
 

src/libcollections/trie.rs

@@ -395,7 +395,7 @@ impl<T> TrieNode<T> {
 
 impl<T> TrieNode<T> {
     fn each_reverse<'a>(&'a self, f: |&uint, &'a T| -> bool) -> bool {
-        for elt in self.children.rev_iter() {
+        for elt in self.children.iter().rev() {
             match *elt {
                 Internal(ref x) => if !x.each_reverse(|i,t| f(i,t)) { return false },
                 External(k, ref v) => if !f(&k, v) { return false },

src/libnum/bigint.rs

@@ -439,7 +439,7 @@ impl Integer for BigUint {
             let bn = *b.data.last().unwrap();
             let mut d = Vec::with_capacity(an.len());
             let mut carry = 0;
-            for elt in an.rev_iter() {
+            for elt in an.iter().rev() {
                 let ai = BigDigit::to_uint(carry, *elt);
                 let di = ai / (bn as uint);
                 assert!(di < BigDigit::base);
@@ -668,7 +668,7 @@ impl ToStrRadix for BigUint {
         fn fill_concat(v: &[BigDigit], radix: uint, l: uint) -> ~str {
             if v.is_empty() { return "0".to_owned() }
             let mut s = StrBuf::with_capacity(v.len() * l);
-            for n in v.rev_iter() {
+            for n in v.iter().rev() {
                 let ss = (*n as uint).to_str_radix(radix);
                 s.push_str("0".repeat(l - ss.len()));
                 s.push_str(ss);
@@ -2187,7 +2187,7 @@ mod bigint_tests {
     fn test_cmp() {
         let vs = [ &[2 as BigDigit], &[1, 1], &[2, 1], &[1, 1, 1] ];
         let mut nums = Vec::new();
-        for s in vs.rev_iter() {
+        for s in vs.iter().rev() {
             nums.push(BigInt::from_slice(Minus, *s));
         }
         nums.push(Zero::zero());

src/librustc/middle/liveness.rs

@@ -927,7 +927,7 @@ impl<'a> Liveness<'a> {
 
     fn propagate_through_exprs(&mut self, exprs: &[@Expr], succ: LiveNode)
                                -> LiveNode {
-        exprs.rev_iter().fold(succ, |succ, expr| {
+        exprs.iter().rev().fold(succ, |succ, expr| {
             self.propagate_through_expr(*expr, succ)
         })
     }

src/librustc/middle/typeck/check/vtable.rs

@@ -1,4 +1,4 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -94,7 +94,7 @@ fn lookup_vtables(vcx: &VtableContext,
     let mut result: Vec<vtable_param_res> =
         substs.tps.iter()
         .rev()
-        .zip(type_param_defs.rev_iter())
+        .zip(type_param_defs.iter().rev())
         .map(|(ty, def)|
             lookup_vtables_for_param(vcx, span, Some(substs),
                                      &*def.bounds, *ty, is_early))

src/librustdoc/lib.rs

@@ -304,7 +304,7 @@ fn rust_input(cratefile: &str, matches: &getopts::Matches) -> Output {
         None => {}
     }
     if default_passes {
-        for name in DEFAULT_PASSES.rev_iter() {
+        for name in DEFAULT_PASSES.iter().rev() {
             passes.unshift(name.to_owned());
         }
     }

src/libserialize/json.rs

@@ -1931,7 +1931,7 @@ impl ::Decoder<DecoderError> for Decoder {
                 };
                 match o.pop(&"fields".to_owned()) {
                     Some(List(l)) => {
-                        for field in l.move_rev_iter() {
+                        for field in l.move_iter().rev() {
                             self.stack.push(field.clone());
                         }
                     },
@@ -2042,7 +2042,7 @@ impl ::Decoder<DecoderError> for Decoder {
         debug!("read_seq()");
         let list = try!(expect!(self.pop(), List));
         let len = list.len();
-        for v in list.move_rev_iter() {
+        for v in list.move_iter().rev() {
             self.stack.push(v);
         }
         f(self, len)