auto merge of #15283 : kwantam/rust/master, r=alexcrichton

Add libunicode; move unicode functions from core

- created new crate, libunicode, below libstd
- split `Char` trait into `Char` (libcore) and `UnicodeChar` (libunicode)
  - Unicode-aware functions now live in libunicode
    - `is_alphabetic`, `is_XID_start`, `is_XID_continue`, `is_lowercase`,
      `is_uppercase`, `is_whitespace`, `is_alphanumeric`, `is_control`, `is_digit`,
      `to_uppercase`, `to_lowercase`
  - added `width` method in UnicodeChar trait
    - determines printed width of character in columns, or None if it is a non-NULL control character
    - takes a boolean argument indicating whether the present context is CJK or not (characters with 'A'mbiguous widths are double-wide in CJK contexts, single-wide otherwise)
- split `StrSlice` into `StrSlice` (libcore) and `UnicodeStrSlice` (libunicode)
  - functionality formerly in `StrSlice` that relied upon Unicode functionality from `Char` is now in `UnicodeStrSlice`
    - `words`, `is_whitespace`, `is_alphanumeric`, `trim`, `trim_left`, `trim_right`
  - also moved `Words` type alias into libunicode because `words` method is in `UnicodeStrSlice`
- unified Unicode tables from libcollections, libcore, and libregex into libunicode
- updated `unicode.py` in `src/etc` to generate aforementioned tables
- generated new tables based on latest Unicode data
- added `UnicodeChar` and `UnicodeStrSlice` traits to prelude
- libunicode is now the collection point for the `std::char` module, combining the libunicode functionality with the `Char` functionality from libcore
  - thus, moved doc comment for `char` from `core::char` to `unicode::char`
- libcollections remains the collection point for `std::str`

The Unicode-aware functions that previously lived in the `Char` and `StrSlice` traits are no longer available to programs that only use libcore. To regain use of these methods, include the libunicode crate and `use` the `UnicodeChar` and/or `UnicodeStrSlice` traits:

    extern crate unicode;
    use unicode::UnicodeChar;
    use unicode::UnicodeStrSlice;
    use unicode::Words; // if you want to use the words() method

NOTE: this does *not* impact programs that use libstd, since UnicodeChar and UnicodeStrSlice have been added to the prelude.

closes #15224
[breaking-change]

5 files changed, 9 insertions, 4 deletions

diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index fe9016453f7..4ef2e51fcf0 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -237,6 +237,7 @@ use str::{Str, StrSlice};
 use str;
 use string::String;
 use uint;
+use unicode::UnicodeChar;
 use vec::Vec;
 
 // Reexports
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 928a1088d0e..586f513835b 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -126,6 +126,7 @@
 #[cfg(test)] #[phase(plugin, link)] extern crate log;
 
 extern crate alloc;
+extern crate unicode;
 extern crate core;
 extern crate core_collections = "collections";
 extern crate core_rand = "rand";
@@ -148,7 +149,6 @@ extern crate rustrt;
 pub use core::any;
 pub use core::bool;
 pub use core::cell;
-pub use core::char;
 pub use core::clone;
 #[cfg(not(test))] pub use core::cmp;
 pub use core::default;
@@ -180,6 +180,8 @@ pub use core_collections::vec;
 pub use rustrt::c_str;
 pub use rustrt::local_data;
 
+pub use unicode::char;
+
 pub use core_sync::comm;
 
 // Run tests with libgreen instead of libnative.
diff --git a/src/libstd/path/windows.rs b/src/libstd/path/windows.rs
index 206f75739e8..5e42d740e03 100644
--- a/src/libstd/path/windows.rs
+++ b/src/libstd/path/windows.rs
@@ -24,6 +24,7 @@ use option::{Option, Some, None};
 use slice::{Vector, ImmutableVector};
 use str::{CharSplits, Str, StrAllocating, StrVector, StrSlice};
 use string::String;
+use unicode::UnicodeChar;
 use vec::Vec;
 
 use super::{contains_nul, BytesContainer, GenericPath, GenericPathUnsafe};
@@ -997,7 +998,7 @@ fn parse_prefix<'a>(mut path: &'a str) -> Option<PathPrefix> {
                 let idx = path.find('\\');
                 if idx == Some(2) && path.as_bytes()[1] == ':' as u8 {
                     let c = path.as_bytes()[0];
-                    if c.is_ascii() && ::char::is_alphabetic(c as char) {
+                    if c.is_ascii() && (c as char).is_alphabetic() {
                         // \\?\C:\ path
                         return Some(VerbatimDiskPrefix);
                     }
@@ -1021,7 +1022,7 @@ fn parse_prefix<'a>(mut path: &'a str) -> Option<PathPrefix> {
     } else if path.len() > 1 && path.as_bytes()[1] == ':' as u8 {
         // C:
         let c = path.as_bytes()[0];
-        if c.is_ascii() && ::char::is_alphabetic(c as char) {
+        if c.is_ascii() && (c as char).is_alphabetic() {
             return Some(DiskPrefix);
         }
     }
diff --git a/src/libstd/prelude.rs b/src/libstd/prelude.rs
index 6d60fc19d5d..83ea33a1e69 100644
--- a/src/libstd/prelude.rs
+++ b/src/libstd/prelude.rs
@@ -89,6 +89,7 @@
 #[doc(no_inline)] pub use slice::{Vector, VectorVector};
 #[doc(no_inline)] pub use slice::MutableVectorAllocating;
 #[doc(no_inline)] pub use string::String;
+#[doc(no_inline)] pub use unicode::{UnicodeChar, UnicodeStrSlice};
 #[doc(no_inline)] pub use vec::Vec;
 
 // Reexported runtime types
diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
index 404887823cb..09922b5ad76 100644
--- a/src/libstd/rt/backtrace.rs
+++ b/src/libstd/rt/backtrace.rs
@@ -12,7 +12,6 @@
 
 #![allow(non_camel_case_types)]
 
-use char::Char;
 use collections::Collection;
 use from_str::from_str;
 use io::{IoResult, Writer};
@@ -22,6 +21,7 @@ use os;
 use result::{Ok, Err};
 use str::StrSlice;
 use sync::atomics;
+use unicode::UnicodeChar;
 
 pub use self::imp::write;