Deprecate the rev_iter pattern in all places where a DoubleEndedIterator is provided (everywhere but treemap)

This commit deprecates rev_iter, mut_rev_iter, move_rev_iter everywhere (except treemap) and also
deprecates related functions like rsplit, rev_components, and rev_str_components. In every case,
these functions can be replaced with the non-reversed form followed by a call to .rev(). To make this
more concrete, a translation table for all functional changes necessary follows:

* container.rev_iter() -> container.iter().rev()
* container.mut_rev_iter() -> container.mut_iter().rev()
* container.move_rev_iter() -> container.move_iter().rev()
* sliceorstr.rsplit(sep) -> sliceorstr.split(sep).rev()
* path.rev_components() -> path.components().rev()
* path.rev_str_components() -> path.str_components().rev()

In terms of the type system, this change also deprecates any specialized reversed iterator types (except
in treemap), opting instead to use Rev directly if any type annotations are needed. However, since
methods directly returning reversed iterators are now discouraged, the need for such annotations should
be small. However, in those cases, the general pattern for conversion is to take whatever follows Rev in
the original reversed name and surround it with Rev<>:

* RevComponents<'a> -> Rev<Components<'a>>
* RevStrComponents<'a> -> Rev<StrComponents<'a>>
* RevItems<'a, T> -> Rev<Items<'a, T>>
* etc.

The reasoning behind this change is that it makes the standard API much simpler without reducing readability,
performance, or power. The presence of functions such as rev_iter adds more boilerplate code to libraries
(all of which simply call .iter().rev()), clutters up the documentation, and only helps code by saving two
characters. Additionally, the numerous type synonyms that were used to make the type signatures look nice
like RevItems add even more boilerplate and clutter up the docs even more. With this change, all that cruft
goes away.

[breaking-change]

1 files changed, 41 insertions, 43 deletions

diff --git a/src/libstd/str.rs b/src/libstd/str.rs
index 99f1c66e702..bc7943dd777 100644
--- a/src/libstd/str.rs
+++ b/src/libstd/str.rs
@@ -343,12 +343,10 @@ impl<'a> DoubleEndedIterator<(uint, char)> for CharOffsets<'a> {
     }
 }
 
-/// External iterator for a string's characters in reverse order.
-/// Use with the `std::iter` module.
+#[deprecated = "replaced by Rev<Chars<'a>>"]
 pub type RevChars<'a> = Rev<Chars<'a>>;
 
-/// External iterator for a string's characters and their byte offsets in reverse order.
-/// Use with the `std::iter` module.
+#[deprecated = "replaced by Rev<CharOffsets<'a>>"]
 pub type RevCharOffsets<'a> = Rev<CharOffsets<'a>>;
 
 /// External iterator for a string's bytes.
@@ -356,8 +354,7 @@ pub type RevCharOffsets<'a> = Rev<CharOffsets<'a>>;
 pub type Bytes<'a> =
     Map<'a, &'a u8, u8, slice::Items<'a, u8>>;
 
-/// External iterator for a string's bytes in reverse order.
-/// Use with the `std::iter` module.
+#[deprecated = "replaced by Rev<Bytes<'a>>"]
 pub type RevBytes<'a> = Rev<Bytes<'a>>;
 
 /// An iterator over the substrings of a string, separated by `sep`.
@@ -372,8 +369,7 @@ pub struct CharSplits<'a, Sep> {
     finished: bool,
 }
 
-/// An iterator over the substrings of a string, separated by `sep`,
-/// starting from the back of the string.
+#[deprecated = "replaced by Rev<CharSplits<'a, Sep>>"]
 pub type RevCharSplits<'a, Sep> = Rev<CharSplits<'a, Sep>>;
 
 /// An iterator over the substrings of a string, separated by `sep`,
@@ -462,7 +458,7 @@ for CharSplits<'a, Sep> {
                 }
             }
         } else {
-            for (idx, ch) in self.string.char_indices_rev() {
+            for (idx, ch) in self.string.char_indices().rev() {
                 if self.sep.matches(ch) {
                     next_split = Some((idx, self.string.char_range_at(idx).next));
                     break;
@@ -1626,21 +1622,23 @@ pub trait StrSlice<'a> {
     /// ```
     fn chars(&self) -> Chars<'a>;
 
-    /// An iterator over the characters of `self`, in reverse order.
-    fn chars_rev(&self) -> RevChars<'a>;
+    /// Do not use this - it is deprecated.
+    #[deprecated = "replaced by .chars().rev()"]
+    fn chars_rev(&self) -> Rev<Chars<'a>>;
 
     /// An iterator over the bytes of `self`
     fn bytes(&self) -> Bytes<'a>;
 
-    /// An iterator over the bytes of `self`, in reverse order
-    fn bytes_rev(&self) -> RevBytes<'a>;
+    /// Do not use this - it is deprecated.
+    #[deprecated = "replaced by .bytes().rev()"]
+    fn bytes_rev(&self) -> Rev<Bytes<'a>>;
 
     /// An iterator over the characters of `self` and their byte offsets.
     fn char_indices(&self) -> CharOffsets<'a>;
 
-    /// An iterator over the characters of `self` and their byte offsets,
-    /// in reverse order.
-    fn char_indices_rev(&self) -> RevCharOffsets<'a>;
+    /// Do not use this - it is deprecated.
+    #[deprecated = "replaced by .char_indices().rev()"]
+    fn char_indices_rev(&self) -> Rev<CharOffsets<'a>>;
 
     /// An iterator over substrings of `self`, separated by characters
     /// matched by `sep`.
@@ -1691,25 +1689,21 @@ pub trait StrSlice<'a> {
     ///
     /// let v: ~[&str] = "A..B..".split_terminator('.').collect();
     /// assert_eq!(v, ~["A", "", "B", ""]);
-    /// ```
-    fn split_terminator<Sep: CharEq>(&self, sep: Sep) -> CharSplits<'a, Sep>;
-
-    /// An iterator over substrings of `self`, separated by characters
-    /// matched by `sep`, in reverse order.
-    ///
-    /// # Example
     ///
-    /// ```rust
-    /// let v: ~[&str] = "Mary had a little lamb".rsplit(' ').collect();
+    /// let v: ~[&str] = "Mary had a little lamb".split(' ').rev().collect();
     /// assert_eq!(v, ~["lamb", "little", "a", "had", "Mary"]);
     ///
-    /// let v: ~[&str] = "abc1def2ghi".rsplit(|c: char| c.is_digit()).collect();
+    /// let v: ~[&str] = "abc1def2ghi".split(|c: char| c.is_digit()).rev().collect();
     /// assert_eq!(v, ~["ghi", "def", "abc"]);
     ///
-    /// let v: ~[&str] = "lionXXtigerXleopard".rsplit('X').collect();
+    /// let v: ~[&str] = "lionXXtigerXleopard".split('X').rev().collect();
     /// assert_eq!(v, ~["leopard", "tiger", "", "lion"]);
     /// ```
-    fn rsplit<Sep: CharEq>(&self, sep: Sep) -> RevCharSplits<'a, Sep>;
+    fn split_terminator<Sep: CharEq>(&self, sep: Sep) -> CharSplits<'a, Sep>;
+
+    /// Do not use this - it is deprecated.
+    #[deprecated = "replaced by .split(sep).rev()"]
+    fn rsplit<Sep: CharEq>(&self, sep: Sep) -> Rev<CharSplits<'a, Sep>>;
 
     /// An iterator over substrings of `self`, separated by characters
     /// matched by `sep`, starting from the end of the string.
@@ -2281,7 +2275,8 @@ impl<'a> StrSlice<'a> for &'a str {
     }
 
     #[inline]
-    fn chars_rev(&self) -> RevChars<'a> {
+    #[deprecated = "replaced by .chars().rev()"]
+    fn chars_rev(&self) -> Rev<Chars<'a>> {
         self.chars().rev()
     }
 
@@ -2291,7 +2286,8 @@ impl<'a> StrSlice<'a> for &'a str {
     }
 
     #[inline]
-    fn bytes_rev(&self) -> RevBytes<'a> {
+    #[deprecated = "replaced by .bytes().rev()"]
+    fn bytes_rev(&self) -> Rev<Bytes<'a>> {
         self.bytes().rev()
     }
 
@@ -2301,7 +2297,8 @@ impl<'a> StrSlice<'a> for &'a str {
     }
 
     #[inline]
-    fn char_indices_rev(&self) -> RevCharOffsets<'a> {
+    #[deprecated = "replaced by .char_indices().rev()"]
+    fn char_indices_rev(&self) -> Rev<CharOffsets<'a>> {
         self.char_indices().rev()
     }
 
@@ -2336,7 +2333,8 @@ impl<'a> StrSlice<'a> for &'a str {
     }
 
     #[inline]
-    fn rsplit<Sep: CharEq>(&self, sep: Sep) -> RevCharSplits<'a, Sep> {
+    #[deprecated = "replaced by .split(sep).rev()"]
+    fn rsplit<Sep: CharEq>(&self, sep: Sep) -> Rev<CharSplits<'a, Sep>> {
         self.split(sep).rev()
     }
 
@@ -2656,7 +2654,7 @@ impl<'a> StrSlice<'a> for &'a str {
         if search.only_ascii() {
             self.bytes().rposition(|b| search.matches(b as char))
         } else {
-            for (index, c) in self.char_indices_rev() {
+            for (index, c) in self.char_indices().rev() {
                 if search.matches(c) { return Some(index); }
             }
             None
@@ -3573,7 +3571,7 @@ mod tests {
         let s = "ศไทย中华Việt Nam".to_owned();
         let v = ~['ศ','ไ','ท','ย','中','华','V','i','ệ','t',' ','N','a','m'];
         let mut pos = s.len();
-        for ch in v.rev_iter() {
+        for ch in v.iter().rev() {
             assert!(s.char_at_reverse(pos) == *ch);
             pos -= from_char(*ch).len();
         }
@@ -3673,7 +3671,7 @@ mod tests {
         let v = ~['m', 'a', 'N', ' ', 't', 'ệ','i','V','华','中','ย','ท','ไ','ศ'];
 
         let mut pos = 0;
-        let mut it = s.chars_rev();
+        let mut it = s.chars().rev();
 
         for c in it {
             assert_eq!(c, v[pos]);
@@ -3716,7 +3714,7 @@ mod tests {
         ];
         let mut pos = v.len();
 
-        for b in s.bytes_rev() {
+        for b in s.bytes().rev() {
             pos -= 1;
             assert_eq!(b, v[pos]);
         }
@@ -3748,7 +3746,7 @@ mod tests {
         let v = ['m', 'a', 'N', ' ', 't', 'ệ','i','V','华','中','ย','ท','ไ','ศ'];
 
         let mut pos = 0;
-        let mut it = s.char_indices_rev();
+        let mut it = s.char_indices().rev();
 
         for c in it {
             assert_eq!(c, (p[pos], v[pos]));
@@ -3765,14 +3763,14 @@ mod tests {
         let split: ~[&str] = data.split(' ').collect();
         assert_eq!( split, ~["\nMäry", "häd", "ä", "little", "lämb\nLittle", "lämb\n"]);
 
-        let mut rsplit: ~[&str] = data.rsplit(' ').collect();
+        let mut rsplit: ~[&str] = data.split(' ').rev().collect();
         rsplit.reverse();
         assert_eq!(rsplit, ~["\nMäry", "häd", "ä", "little", "lämb\nLittle", "lämb\n"]);
 
         let split: ~[&str] = data.split(|c: char| c == ' ').collect();
         assert_eq!( split, ~["\nMäry", "häd", "ä", "little", "lämb\nLittle", "lämb\n"]);
 
-        let mut rsplit: ~[&str] = data.rsplit(|c: char| c == ' ').collect();
+        let mut rsplit: ~[&str] = data.split(|c: char| c == ' ').rev().collect();
         rsplit.reverse();
         assert_eq!(rsplit, ~["\nMäry", "häd", "ä", "little", "lämb\nLittle", "lämb\n"]);
 
@@ -3780,14 +3778,14 @@ mod tests {
         let split: ~[&str] = data.split('ä').collect();
         assert_eq!( split, ~["\nM", "ry h", "d ", " little l", "mb\nLittle l", "mb\n"]);
 
-        let mut rsplit: ~[&str] = data.rsplit('ä').collect();
+        let mut rsplit: ~[&str] = data.split('ä').rev().collect();
         rsplit.reverse();
         assert_eq!(rsplit, ~["\nM", "ry h", "d ", " little l", "mb\nLittle l", "mb\n"]);
 
         let split: ~[&str] = data.split(|c: char| c == 'ä').collect();
         assert_eq!( split, ~["\nM", "ry h", "d ", " little l", "mb\nLittle l", "mb\n"]);
 
-        let mut rsplit: ~[&str] = data.rsplit(|c: char| c == 'ä').collect();
+        let mut rsplit: ~[&str] = data.split(|c: char| c == 'ä').rev().collect();
         rsplit.reverse();
         assert_eq!(rsplit, ~["\nM", "ry h", "d ", " little l", "mb\nLittle l", "mb\n"]);
     }
@@ -4103,7 +4101,7 @@ mod bench {
         let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";
         let len = s.char_len();
 
-        b.iter(|| assert_eq!(s.chars_rev().len(), len));
+        b.iter(|| assert_eq!(s.chars().rev().len(), len));
     }
 
     #[bench]
@@ -4119,7 +4117,7 @@ mod bench {
         let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";
         let len = s.char_len();
 
-        b.iter(|| assert_eq!(s.char_indices_rev().len(), len));
+        b.iter(|| assert_eq!(s.char_indices().rev().len(), len));
     }
 
     #[bench]