auto merge of #7060 : huonw/rust/more-str, r=thestinger

There are now only half-a-dozen or so functions left `std::str` that should be methods.

Highlights:
- `.substr` was removed, since most of the uses of it in the code base were actually incorrect (it had a weird mixing of a byte index and a unicode character count), adding `.slice_chars` if one wants to handle characters, and the normal `.slice` method to handle bytes.
- Code duplication between the two impls for `connect` and `concat` was removed via a new `Str` trait, that is purely designed to allow an explicit -> `&str` conversion (`.as_slice()`)
- Deconfuse the 5 different functions for converting to `[u8]` (3 of which had actually incorrect documentation: implying that they didn't have the null terminator), into 3: `as_bytes` (all strings), `as_bytes_with_null` (`&'static str`, `@str` and `~str`) and `as_bytes_with_null_consume` (`~str`). None of these allocate, unlike the old versions.

(cc @thestinger)

doc/tutorial.md

@@ -1410,7 +1410,7 @@ let new_favorite_crayon_name = favorite_crayon_name.trim();
 
 if favorite_crayon_name.len() > 5 {
    // Create a substring
-   println(favorite_crayon_name.substr(0, 5));
+   println(favorite_crayon_name.slice_chars(0, 5));
 }
 ~~~
 

src/compiletest/runtest.rs

@@ -171,8 +171,8 @@ fn run_pretty_test(config: &config, props: &TestProps, testfile: &Path) {
     if props.pp_exact.is_some() {
         // Now we have to care about line endings
         let cr = ~"\r";
-        actual = str::replace(actual, cr, "");
-        expected = str::replace(expected, cr, "");
+        actual = actual.replace(cr, "");
+        expected = expected.replace(cr, "");
     }
 
     compare_source(expected, actual);
@@ -238,7 +238,7 @@ fn run_debuginfo_test(config: &config, props: &TestProps, testfile: &Path) {
     // do not optimize debuginfo tests
     let mut config = match config.rustcflags {
         Some(ref flags) => config {
-            rustcflags: Some(str::replace(*flags, "-O", "")),
+            rustcflags: Some(flags.replace("-O", "")),
             .. copy *config
         },
         None => copy *config
@@ -254,7 +254,7 @@ fn run_debuginfo_test(config: &config, props: &TestProps, testfile: &Path) {
     }
 
     // write debugger script
-    let script_str = str::append(cmds, "\nquit\n");
+    let script_str = cmds.append("\nquit\n");
     debug!("script_str = %s", script_str);
     dump_output_file(config, testfile, script_str, "debugger.script");
 

src/libextra/base64.rs

@@ -12,7 +12,6 @@
 
 use core::prelude::*;
 
-use core::str;
 use core::vec;
 
 /// A trait for converting a value to base64 encoding.
@@ -111,7 +110,7 @@ impl<'self> ToBase64 for &'self str {
      *
      */
     fn to_base64(&self) -> ~str {
-        str::to_bytes(*self).to_base64()
+        self.as_bytes().to_base64()
     }
 }
 
@@ -224,7 +223,7 @@ impl<'self> FromBase64 for &'self str {
      * ~~~
      */
     fn from_base64(&self) -> ~[u8] {
-        str::to_bytes(*self).from_base64()
+        self.as_bytes().from_base64()
     }
 }
 
@@ -245,12 +244,12 @@ fn test_to_base64() {
 
     #[test]
     fn test_from_base64() {
-        assert_eq!("".from_base64(), str::to_bytes(""));
-        assert_eq!("Zg==".from_base64(), str::to_bytes("f"));
-        assert_eq!("Zm8=".from_base64(), str::to_bytes("fo"));
-        assert_eq!("Zm9v".from_base64(), str::to_bytes("foo"));
-        assert_eq!("Zm9vYg==".from_base64(), str::to_bytes("foob"));
-        assert_eq!("Zm9vYmE=".from_base64(), str::to_bytes("fooba"))
-        assert_eq!("Zm9vYmFy".from_base64(), str::to_bytes("foobar"));
+        assert_eq!("".from_base64(), "".as_bytes().to_owned());
+        assert_eq!("Zg==".from_base64(), "f".as_bytes().to_owned());
+        assert_eq!("Zm8=".from_base64(), "fo".as_bytes().to_owned());
+        assert_eq!("Zm9v".from_base64(), "foo".as_bytes().to_owned());
+        assert_eq!("Zm9vYg==".from_base64(), "foob".as_bytes().to_owned());
+        assert_eq!("Zm9vYmE=".from_base64(), "fooba".as_bytes().to_owned());
+        assert_eq!("Zm9vYmFy".from_base64(), "foobar".as_bytes().to_owned());
     }
 }

src/libextra/ebml.rs

@@ -607,7 +607,6 @@ pub mod writer {
 
     use core::cast;
     use core::io;
-    use core::str;
 
     // ebml writing
     pub struct Encoder {
@@ -725,7 +724,7 @@ pub fn wr_tagged_i8(&mut self, tag_id: uint, v: i8) {
         }
 
         pub fn wr_tagged_str(&mut self, tag_id: uint, v: &str) {
-            str::byte_slice(v, |b| self.wr_tagged_bytes(tag_id, b));
+            self.wr_tagged_bytes(tag_id, v.as_bytes());
         }
 
         pub fn wr_bytes(&mut self, b: &[u8]) {
@@ -735,7 +734,7 @@ pub fn wr_bytes(&mut self, b: &[u8]) {
 
         pub fn wr_str(&mut self, s: &str) {
             debug!("Write str: %?", s);
-            self.writer.write(str::to_bytes(s));
+            self.writer.write(s.as_bytes());
         }
     }
 

src/libextra/fileinput.rs

@@ -487,7 +487,7 @@ fn test_fileinput_read() {
         let mut buf : ~[u8] = vec::from_elem(6, 0u8);
         let count = fi.read(buf, 10);
         assert_eq!(count, 6);
-        assert_eq!(buf, "0\n1\n2\n".to_bytes());
+        assert_eq!(buf, "0\n1\n2\n".as_bytes().to_owned());
         assert!(fi.eof())
         assert_eq!(fi.state().line_num, 3);
     }

src/libextra/flatpipes.rs

@@ -450,7 +450,7 @@ pub fn deserialize_buffer<D: Decoder + FromReader,
                               T: Decodable<D>>(
                               buf: &[u8])
                               -> T {
-        let buf = vec::to_owned(buf);
+        let buf = buf.to_owned();
         let buf_reader = @BufReader::new(buf);
         let reader = buf_reader as @Reader;
         let mut deser: D = FromReader::from_reader(reader);

src/libextra/getopts.rs

@@ -345,7 +345,7 @@ pub fn getopts(args: &[~str], opts: &[Opt]) -> Result {
         }
         i += 1;
     }
-    return Ok(Matches {opts: vec::to_owned(opts),
+    return Ok(Matches {opts: opts.to_owned(),
                vals: vals,
                free: free});
 }
@@ -447,7 +447,7 @@ pub fn opt_default(mm: &Matches, nm: &str, def: &str) -> Option<~str> {
     let vals = opt_vals(mm, nm);
     if vals.is_empty() { return None::<~str>; }
     return match vals[0] { Val(ref s) => Some::<~str>(copy *s),
-                           _      => Some::<~str>(str::to_owned(def)) }
+                           _      => Some::<~str>(def.to_owned()) }
 }
 
 #[deriving(Eq)]
@@ -487,10 +487,10 @@ pub fn reqopt(short_name: &str, long_name: &str,
                   desc: &str, hint: &str) -> OptGroup {
         let len = short_name.len();
         assert!(len == 1 || len == 0);
-        return OptGroup { short_name: str::to_owned(short_name),
-                long_name: str::to_owned(long_name),
-                hint: str::to_owned(hint),
-                desc: str::to_owned(desc),
+        return OptGroup { short_name: short_name.to_owned(),
+                long_name: long_name.to_owned(),
+                hint: hint.to_owned(),
+                desc: desc.to_owned(),
                 hasarg: Yes,
                 occur: Req};
     }
@@ -500,10 +500,10 @@ pub fn optopt(short_name: &str, long_name: &str,
                   desc: &str, hint: &str) -> OptGroup {
         let len = short_name.len();
         assert!(len == 1 || len == 0);
-        return OptGroup {short_name: str::to_owned(short_name),
-                long_name: str::to_owned(long_name),
-                hint: str::to_owned(hint),
-                desc: str::to_owned(desc),
+        return OptGroup {short_name: short_name.to_owned(),
+                long_name: long_name.to_owned(),
+                hint: hint.to_owned(),
+                desc: desc.to_owned(),
                 hasarg: Yes,
                 occur: Optional};
     }
@@ -513,10 +513,10 @@ pub fn optflag(short_name: &str, long_name: &str,
                    desc: &str) -> OptGroup {
         let len = short_name.len();
         assert!(len == 1 || len == 0);
-        return OptGroup {short_name: str::to_owned(short_name),
-                long_name: str::to_owned(long_name),
+        return OptGroup {short_name: short_name.to_owned(),
+                long_name: long_name.to_owned(),
                 hint: ~"",
-                desc: str::to_owned(desc),
+                desc: desc.to_owned(),
                 hasarg: No,
                 occur: Optional};
     }
@@ -526,10 +526,10 @@ pub fn optflagopt(short_name: &str, long_name: &str,
                       desc: &str, hint: &str) -> OptGroup {
         let len = short_name.len();
         assert!(len == 1 || len == 0);
-        return OptGroup {short_name: str::to_owned(short_name),
-                long_name: str::to_owned(long_name),
-                hint: str::to_owned(hint),
-                desc: str::to_owned(desc),
+        return OptGroup {short_name: short_name.to_owned(),
+                long_name: long_name.to_owned(),
+                hint: hint.to_owned(),
+                desc: desc.to_owned(),
                 hasarg: Maybe,
                 occur: Optional};
     }
@@ -542,10 +542,10 @@ pub fn optmulti(short_name: &str, long_name: &str,
                     desc: &str, hint: &str) -> OptGroup {
         let len = short_name.len();
         assert!(len == 1 || len == 0);
-        return OptGroup {short_name: str::to_owned(short_name),
-                long_name: str::to_owned(long_name),
-                hint: str::to_owned(hint),
-                desc: str::to_owned(desc),
+        return OptGroup {short_name: short_name.to_owned(),
+                long_name: long_name.to_owned(),
+                hint: hint.to_owned(),
+                desc: desc.to_owned(),
                 hasarg: Yes,
                 occur: Multi};
     }
@@ -593,7 +593,7 @@ pub fn getopts(args: &[~str], opts: &[OptGroup]) -> ::getopts::Result {
      */
     pub fn usage(brief: &str, opts: &[OptGroup]) -> ~str {
 
-        let desc_sep = ~"\n" + str::repeat(" ", 24);
+        let desc_sep = ~"\n" + " ".repeat(24);
 
         let rows = vec::map(opts, |optref| {
             let OptGroup{short_name: short_name,
@@ -603,7 +603,7 @@ pub fn usage(brief: &str, opts: &[OptGroup]) -> ~str {
                          hasarg: hasarg,
                          _} = copy *optref;
 
-            let mut row = str::repeat(" ", 4);
+            let mut row = " ".repeat(4);
 
             // short option
             row += match short_name.len() {
@@ -629,7 +629,7 @@ pub fn usage(brief: &str, opts: &[OptGroup]) -> ~str {
             // here we just need to indent the start of the description
             let rowlen = row.len();
             row += if rowlen < 24 {
-                str::repeat(" ", 24 - rowlen)
+                " ".repeat(24 - rowlen)
             } else {
                 copy desc_sep
             };
@@ -654,7 +654,7 @@ pub fn usage(brief: &str, opts: &[OptGroup]) -> ~str {
             row
         });
 
-        return str::to_owned(brief) +
+        return brief.to_owned() +
                "\n\nOptions:\n" +
                rows.connect("\n") +
                "\n\n";

src/libextra/md4.rs

@@ -10,7 +10,6 @@
 
 use core::prelude::*;
 
-use core::str;
 use core::uint;
 use core::vec;
 
@@ -30,7 +29,7 @@ pub fn md4(msg: &[u8]) -> Quad {
     let orig_len: u64 = (msg.len() * 8u) as u64;
 
     // pad message
-    let mut msg = vec::append(vec::to_owned(msg), [0x80u8]);
+    let mut msg = vec::append(msg.to_owned(), [0x80u8]);
     let mut bitlen = orig_len + 8u64;
     while (bitlen + 64u64) % 512u64 > 0u64 {
         msg.push(0u8);
@@ -129,7 +128,7 @@ fn app(a: u32, b: u32, c: u32, d: u32, f: &fn(u32)) {
 
 /// Calculates the md4 hash of a string, returning the hex-encoded version of
 /// the hash
-pub fn md4_text(msg: &str) -> ~str { md4_str(str::to_bytes(msg)) }
+pub fn md4_text(msg: &str) -> ~str { md4_str(msg.as_bytes()) }
 
 #[test]
 fn test_md4() {

src/libextra/net_tcp.rs

@@ -1636,7 +1636,7 @@ pub fn impl_gl_tcp_ipv4_get_peer_addr() {
         assert_eq!(net::ip::get_port(&sock.get_peer_addr()), 8887);
 
         // Fulfill the protocol the test server expects
-        let resp_bytes = str::to_bytes("ping");
+        let resp_bytes = "ping".as_bytes().to_owned();
         tcp_write_single(&sock, resp_bytes);
         debug!("message sent");
         sock.read(0u);
@@ -1756,9 +1756,7 @@ pub fn impl_gl_tcp_ipv4_server_client_reader_writer() {
         buf_write(sock_buf, expected_req);
 
         // so contrived!
-        let actual_resp = do str::as_bytes(&expected_resp.to_str()) |resp_buf| {
-            buf_read(sock_buf, resp_buf.len())
-        };
+        let actual_resp = buf_read(sock_buf, expected_resp.as_bytes().len());
 
         let actual_req = server_result_po.recv();
         debug!("REQ: expected: '%s' actual: '%s'",
@@ -1810,11 +1808,10 @@ pub fn impl_tcp_socket_impl_reader_handles_eof() {
 
     fn buf_write<W:io::Writer>(w: &W, val: &str) {
         debug!("BUF_WRITE: val len %?", val.len());
-        do str::byte_slice(val) |b_slice| {
-            debug!("BUF_WRITE: b_slice len %?",
-                            b_slice.len());
-            w.write(b_slice)
-        }
+        let b_slice = val.as_bytes();
+        debug!("BUF_WRITE: b_slice len %?",
+               b_slice.len());
+        w.write(b_slice)
     }
 
     fn buf_read<R:io::Reader>(r: &R, len: uint) -> ~str {
@@ -1877,7 +1874,8 @@ fn run_tcp_test_server(server_ip: &str, server_port: uint, resp: ~str,
                             server_ch.send(
                                 str::from_bytes(data));
                             debug!("SERVER: before write");
-                            tcp_write_single(&sock, str::to_bytes(resp_cell2.take()));
+                            let s = resp_cell2.take();
+                            tcp_write_single(&sock, s.as_bytes().to_owned());
                             debug!("SERVER: after write.. die");
                             kill_ch.send(None);
                           }
@@ -1949,7 +1947,7 @@ fn run_tcp_test_client(server_ip: &str, server_port: uint, resp: &str,
         }
         else {
             let sock = result::unwrap(connect_result);
-            let resp_bytes = str::to_bytes(resp);
+            let resp_bytes = resp.as_bytes().to_owned();
             tcp_write_single(&sock, resp_bytes);
             let read_result = sock.read(0u);
             if read_result.is_err() {

src/libextra/net_url.rs

@@ -1060,7 +1060,7 @@ fn test_decode_form_urlencoded() {
         /*
         assert_eq!(decode_form_urlencoded([]).len(), 0);
 
-        let s = str::to_bytes("a=1&foo+bar=abc&foo+bar=12+%3D+34");
+        let s = "a=1&foo+bar=abc&foo+bar=12+%3D+34".as_bytes();
         let form = decode_form_urlencoded(s);
         assert_eq!(form.len(), 2);
         assert_eq!(form.get_ref(&~"a"), &~[~"1"]);

src/libextra/num/bigint.rs

@@ -524,7 +524,7 @@ fn fill_concat(v: &[BigDigit], radix: uint, l: uint) -> ~str {
                 let s = uint::to_str_radix(*n as uint, radix);
                 str::from_chars(vec::from_elem(l - s.len(), '0')) + s
             }).concat();
-            s.trim_left_chars(['0']).to_owned()
+            s.trim_left_chars(&'0').to_owned()
         }
     }
 }
@@ -534,7 +534,7 @@ impl FromStrRadix for BigUint {
 
     pub fn from_str_radix(s: &str, radix: uint)
         -> Option<BigUint> {
-        BigUint::parse_bytes(str::to_bytes(s), radix)
+        BigUint::parse_bytes(s.as_bytes(), radix)
     }
 }
 
@@ -564,7 +564,7 @@ pub fn from_uint(n: uint) -> BigUint {
     /// Creates and initializes an BigUint.
 
     pub fn from_slice(slice: &[BigDigit]) -> BigUint {
-        return BigUint::new(vec::to_owned(slice));
+        return BigUint::new(slice.to_owned());
     }
 
     /// Creates and initializes an BigUint.
@@ -1090,7 +1090,7 @@ impl FromStrRadix for BigInt {
 
     fn from_str_radix(s: &str, radix: uint)
         -> Option<BigInt> {
-        BigInt::parse_bytes(str::to_bytes(s), radix)
+        BigInt::parse_bytes(s.as_bytes(), radix)
     }
 }
 

src/libextra/rope.rs

@@ -84,9 +84,9 @@ pub fn of_str(str: @~str) -> Rope {
  *
  * # Return value
  *
- * A rope representing the same string as `str.substr(byte_offset,
- * byte_len)`.  Depending on `byte_len`, this rope may be empty, flat
- * or complex.
+ * A rope representing the same string as `str.slice(byte_offset,
+ * byte_offset + byte_len)`.  Depending on `byte_len`, this rope may
+ * be empty, flat or complex.
  *
  * # Performance note
  *
@@ -564,7 +564,6 @@ pub mod node {
     use rope::node;
 
     use core::cast;
-    use core::str;
     use core::uint;
     use core::vec;
 
@@ -588,7 +587,7 @@ pub enum Root {
      * * char_len - The number of chars in the leaf.
      * * content - Contents of the leaf.
      *
-     *     Note that we can have `char_len < str::char_len(content)`, if
+     *     Note that we can have `char_len < content.char_len()`, if
      *     this leaf is only a subset of the string. Also note that the
      *     string can be shared between several ropes, e.g. for indexing
      *     purposes.
@@ -680,7 +679,7 @@ pub fn of_str(str: @~str) -> @Node {
      */
     pub fn of_substr(str: @~str, byte_start: uint, byte_len: uint) -> @Node {
         return of_substr_unsafer(str, byte_start, byte_len,
-                              str::count_chars(*str, byte_start, byte_len));
+                                 str.slice(byte_start, byte_start + byte_len).char_len());
     }
 
     /**
@@ -734,7 +733,7 @@ pub fn of_substr_unsafer(str: @~str, byte_start: uint, byte_len: uint,
                     if i == 0u  { first_leaf_char_len }
                     else { hint_max_leaf_char_len };
                 let chunk_byte_len =
-                    str::count_bytes(*str, offset, chunk_char_len);
+                    str.slice_from(offset).slice_chars(0, chunk_char_len).len();
                 nodes[i] = @Leaf(Leaf {
                     byte_offset: offset,
                     byte_len: chunk_byte_len,
@@ -938,7 +937,7 @@ pub fn sub_bytes(node: @Node, byte_offset: uint,
             match (*node) {
               node::Leaf(x) => {
                 let char_len =
-                    str::count_chars(*x.content, byte_offset, byte_len);
+                    x.content.slice(byte_offset, byte_offset + byte_len).char_len();
                 return @Leaf(Leaf {
                     byte_offset: byte_offset,
                     byte_len: byte_len,
@@ -1002,9 +1001,9 @@ pub fn sub_chars(node: @Node, char_offset: uint,
                     return node;
                 }
                 let byte_offset =
-                    str::count_bytes(*x.content, 0u, char_offset);
+                    x.content.slice_chars(0, char_offset).len();
                 let byte_len    =
-                    str::count_bytes(*x.content, byte_offset, char_len);
+                    x.content.slice_from(byte_offset).slice_chars(0, char_len).len();
                 return @Leaf(Leaf {
                     byte_offset: byte_offset,
                     byte_len: byte_len,
@@ -1312,7 +1311,7 @@ fn of_string1() {
         let sample = @~"0123456789ABCDE";
         let r      = of_str(sample);
 
-        assert_eq!(char_len(r), str::char_len(*sample));
+        assert_eq!(char_len(r), sample.char_len());
         assert!(rope_to_string(r) == *sample);
     }
 
@@ -1328,7 +1327,7 @@ fn of_string2() {
         }
         let sample = @copy *buf;
         let r      = of_str(sample);
-        assert!(char_len(r) == str::char_len(*sample));
+        assert_eq!(char_len(r), sample.char_len());
         assert!(rope_to_string(r) == *sample);
 
         let mut string_iter = 0u;
@@ -1374,7 +1373,7 @@ fn iter1() {
             }
         }
 
-        assert_eq!(len, str::char_len(*sample));
+        assert_eq!(len, sample.char_len());
     }
 
     #[test]

src/libextra/sha1.rs

@@ -25,7 +25,6 @@
 use core::prelude::*;
 
 use core::iterator::IteratorUtil;
-use core::str;
 use core::uint;
 use core::vec;
 
@@ -246,8 +245,7 @@ fn reset(&mut self) {
         }
         fn input(&mut self, msg: &const [u8]) { add_input(self, msg); }
         fn input_str(&mut self, msg: &str) {
-            let bs = str::to_bytes(msg);
-            add_input(self, bs);
+            add_input(self, msg.as_bytes());
         }
         fn result(&mut self) -> ~[u8] { return mk_result(self); }
         fn result_str(&mut self) -> ~str {

src/libextra/stats.rs

@@ -13,7 +13,6 @@
 use core::prelude::*;
 
 use core::iterator::*;
-use core::vec;
 use core::f64;
 use core::cmp;
 use core::num;
@@ -57,7 +56,7 @@ fn mean(self) -> f64 {
 
     fn median(self) -> f64 {
         assert!(self.len() != 0);
-        let mut tmp = vec::to_owned(self);
+        let mut tmp = self.to_owned();
         sort::tim_sort(tmp);
         if tmp.len() & 1 == 0 {
             let m = tmp.len() / 2;

src/libextra/terminfo/parm.rs

@@ -85,11 +85,14 @@ pub fn expand(cap: &[u8], params: &mut [Param], sta: &mut [Param], dyn: &mut [Pa
                         _       => return Err(~"a non-char was used with %c")
                     },
                     's' => match stack.pop() {
-                        String(s) => output.push_all(s.to_bytes()),
+                        String(s) => output.push_all(s.as_bytes()),
                         _         => return Err(~"a non-str was used with %s")
                     },
                     'd' => match stack.pop() {
-                        Number(x) => output.push_all(x.to_str().to_bytes()),
+                        Number(x) => {
+                            let s = x.to_str();
+                            output.push_all(s.as_bytes())
+                        }
                         _         => return Err(~"a non-number was used with %d")
                     },
                     'p' => state = PushParam,

src/libextra/terminfo/searcher.rs

@@ -12,7 +12,7 @@
 /// Does not support hashed database, only filesystem!
 
 use core::prelude::*;
-use core::{os};
+use core::{os, str};
 use core::os::getenv;
 use core::io::{file_reader, Reader};
 use core::iterator::IteratorUtil;
@@ -27,7 +27,7 @@ pub fn get_dbpath_for_term(term: &str) -> Option<~path> {
     let homedir = os::homedir();
 
     let mut dirs_to_search = ~[];
-    let first_char = term.substr(0, 1);
+    let first_char = term.char_at(0);
 
     // Find search directory
     match getenv("TERMINFO") {
@@ -57,12 +57,12 @@ pub fn get_dbpath_for_term(term: &str) -> Option<~path> {
 
     // Look for the terminal in all of the search directories
     for dirs_to_search.each |p| {
-        let newp = ~p.push_many(&[first_char.to_owned(), term.to_owned()]);
+        let newp = ~p.push_many(&[str::from_char(first_char), term.to_owned()]);
         if os::path_exists(p) && os::path_exists(newp) {
             return Some(newp);
         }
         // on some installations the dir is named after the hex of the char (e.g. OS X)
-        let newp = ~p.push_many(&[fmt!("%x", first_char[0] as uint), term.to_owned()]);
+        let newp = ~p.push_many(&[fmt!("%x", first_char as uint), term.to_owned()]);
         if os::path_exists(p) && os::path_exists(newp) {
             return Some(newp);
         }

src/libextra/time.rs

@@ -1029,7 +1029,7 @@ fn test_strptime() {
 
         fn test(s: &str, format: &str) -> bool {
             match strptime(s, format) {
-              Ok(ref tm) => tm.strftime(format) == str::to_owned(s),
+              Ok(ref tm) => tm.strftime(format) == s.to_owned(),
               Err(e) => fail!(e)
             }
         }

src/libextra/treemap.rs

@@ -769,10 +769,10 @@ fn test_clear() {
     fn u8_map() {
         let mut m = TreeMap::new();
 
-        let k1 = str::to_bytes("foo");
-        let k2 = str::to_bytes("bar");
-        let v1 = str::to_bytes("baz");
-        let v2 = str::to_bytes("foobar");
+        let k1 = "foo".as_bytes();
+        let k2 = "bar".as_bytes();
+        let v1 = "baz".as_bytes();
+        let v2 = "foobar".as_bytes();
 
         m.insert(copy k1, copy v1);
         m.insert(copy k2, copy v2);

src/libextra/uv_ll.rs

@@ -1368,7 +1368,7 @@ fn impl_uv_tcp_request(ip: &str, port: int, req_str: &str,
             // In C, this would be a malloc'd or stack-allocated
             // struct that we'd cast to a void* and store as the
             // data field in our uv_connect_t struct
-            let req_str_bytes = str::to_bytes(req_str);
+            let req_str_bytes = req_str.as_bytes();
             let req_msg_ptr: *u8 = vec::raw::to_ptr(req_str_bytes);
             debug!("req_msg ptr: %u", req_msg_ptr as uint);
             let req_msg = ~[
@@ -1626,7 +1626,7 @@ fn impl_uv_tcp_server(server_ip: &str,
             let server_write_req = write_t();
             let server_write_req_ptr: *uv_write_t = &server_write_req;
 
-            let resp_str_bytes = str::to_bytes(server_resp_msg);
+            let resp_str_bytes = server_resp_msg.as_bytes();
             let resp_msg_ptr: *u8 = vec::raw::to_ptr(resp_str_bytes);
             debug!("resp_msg ptr: %u", resp_msg_ptr as uint);
             let resp_msg = ~[

src/libfuzzer/fuzzer.rc

@@ -328,7 +328,7 @@ pub fn check_variants_T<T:Copy>(crate: @ast::crate,
     if L < 100 {
         do under(uint::min(L, 20)) |i| {
             error!("Replacing... #%?", uint::to_str(i));
-            let fname = str::to_owned(filename.to_str());
+            let fname = filename.to_str();
             do under(uint::min(L, 30)) |j| {
                 let fname = fname.to_str();
                 error!("With... %?", stringifier(things[j], intr));

src/librust/rust.rc

@@ -36,7 +36,6 @@ use core::io;
 use core::os;
 use core::run;
 use core::libc::exit;
-use core::str;
 
 // For bootstrapping.
 mod std {
@@ -225,7 +224,7 @@ fn usage() {
     );
 
     for commands.each |command| {
-        let padding = str::repeat(" ", indent - command.cmd.len());
+        let padding = " ".repeat(indent - command.cmd.len());
         io::println(fmt!("    %s%s%s",
                          command.cmd, padding, command.usage_line));
     }

src/librustc/back/link.rs

@@ -50,8 +50,7 @@ pub enum output_type {
 }
 
 fn write_string<W:Writer>(writer: &mut W, string: &str) {
-    let buffer = str::as_bytes_slice(string);
-    writer.write(buffer);
+    writer.write(string.as_bytes());
 }
 
 pub fn llvm_err(sess: Session, msg: ~str) -> ! {
@@ -637,7 +636,7 @@ pub fn symbol_hash(tcx: ty::ctxt,
     write_string(symbol_hasher, encoder::encoded_ty(tcx, t));
     let mut hash = truncated_hash_result(symbol_hasher);
     // Prefix with _ so that it never blends into adjacent digits
-    str::unshift_char(&mut hash, '_');
+    hash.unshift_char('_');
     // tjc: allocation is unfortunate; need to change core::hash
     hash.to_managed()
 }

src/librustc/driver/driver.rs

@@ -29,7 +29,6 @@
 use core::int;
 use core::io;
 use core::os;
-use core::str;
 use core::vec;
 use extra::getopts::groups::{optopt, optmulti, optflag, optflagopt};
 use extra::getopts::{opt_present};
@@ -96,9 +95,9 @@ pub fn default_configuration(sess: Session, argv0: @~str, input: &input) ->
     };
 
     return ~[ // Target bindings.
-         attr::mk_word_item(@str::to_owned(os::FAMILY)),
+         attr::mk_word_item(@os::FAMILY.to_owned()),
          mk(@~"target_os", @tos),
-         mk(@~"target_family", @str::to_owned(os::FAMILY)),
+         mk(@~"target_family", @os::FAMILY.to_owned()),
          mk(@~"target_arch", @arch),
          mk(@~"target_endian", @end),
          mk(@~"target_word_size", @wordsz),
@@ -590,12 +589,12 @@ pub fn build_session_options(binary: @~str,
 
         // FIXME: #4318 Instead of to_ascii and to_str_ascii, could use
         // to_ascii_consume and to_str_consume to not do a unnecessary copy.
-        let level_short = level_name.substr(0,1);
+        let level_short = level_name.slice_chars(0, 1);
         let level_short = level_short.to_ascii().to_upper().to_str_ascii();
         let flags = vec::append(getopts::opt_strs(matches, level_short),
                                 getopts::opt_strs(matches, level_name));
         for flags.each |lint_name| {
-            let lint_name = str::replace(*lint_name, "-", "_");
+            let lint_name = lint_name.replace("-", "_");
             match lint_dict.find(&lint_name) {
               None => {
                 early_error(demitter, fmt!("unknown %s flag: %s",

src/librustc/metadata/decoder.rs

@@ -570,7 +570,7 @@ pub fn maybe_get_item_ast(cdata: cmd, tcx: ty::ctxt,
     let item_doc = lookup_item(id, cdata.data);
     let path = {
         let item_path = item_path(item_doc);
-        vec::to_owned(item_path.init())
+        item_path.init().to_owned()
     };
     match decode_inlined_item(cdata, tcx, copy path, item_doc) {
       Some(ref ii) => csearch::found((/*bad*/copy *ii)),

src/librustc/metadata/encoder.rs

@@ -202,7 +202,8 @@ fn encode_type_param_bounds(ebml_w: &mut writer::Encoder,
 
 fn encode_variant_id(ebml_w: &mut writer::Encoder, vid: def_id) {
     ebml_w.start_tag(tag_items_data_item_variant);
-    ebml_w.writer.write(str::to_bytes(def_to_str(vid)));
+    let s = def_to_str(vid);
+    ebml_w.writer.write(s.as_bytes());
     ebml_w.end_tag();
 }
 
@@ -271,7 +272,7 @@ fn encode_symbol(ecx: @EncodeContext,
     match ecx.item_symbols.find(&id) {
         Some(x) => {
             debug!("encode_symbol(id=%?, str=%s)", id, *x);
-            ebml_w.writer.write(str::to_bytes(*x));
+            ebml_w.writer.write(x.as_bytes());
         }
         None => {
             ecx.diag.handler().bug(
@@ -285,7 +286,7 @@ fn encode_discriminant(ecx: @EncodeContext,
                        ebml_w: &mut writer::Encoder,
                        id: node_id) {
     ebml_w.start_tag(tag_items_data_item_symbol);
-    ebml_w.writer.write(str::to_bytes(*ecx.discrim_symbols.get_copy(&id)));
+    ebml_w.writer.write(ecx.discrim_symbols.get_copy(&id).as_bytes());
     ebml_w.end_tag();
 }
 
@@ -293,13 +294,15 @@ fn encode_disr_val(_: @EncodeContext,
                    ebml_w: &mut writer::Encoder,
                    disr_val: int) {
     ebml_w.start_tag(tag_disr_val);
-    ebml_w.writer.write(str::to_bytes(int::to_str(disr_val)));
+    let s = int::to_str(disr_val);
+    ebml_w.writer.write(s.as_bytes());
     ebml_w.end_tag();
 }
 
 fn encode_parent_item(ebml_w: &mut writer::Encoder, id: def_id) {
     ebml_w.start_tag(tag_items_data_parent_item);
-    ebml_w.writer.write(str::to_bytes(def_to_str(id)));
+    let s = def_to_str(id);
+    ebml_w.writer.write(s.as_bytes());
     ebml_w.end_tag();
 }
 
@@ -954,7 +957,8 @@ fn add_to_index_(item: @item, ebml_w: &writer::Encoder,
         for methods.each |m| {
             ebml_w.start_tag(tag_item_impl_method);
             let method_def_id = local_def(m.id);
-            ebml_w.writer.write(str::to_bytes(def_to_str(method_def_id)));
+            let s = def_to_str(method_def_id);
+            ebml_w.writer.write(s.as_bytes());
             ebml_w.end_tag();
         }
         for opt_trait.iter().advance |ast_trait_ref| {
@@ -1218,7 +1222,7 @@ fn encode_meta_item(ebml_w: &mut writer::Encoder, mi: @meta_item) {
       meta_word(name) => {
         ebml_w.start_tag(tag_meta_item_word);
         ebml_w.start_tag(tag_meta_item_name);
-        ebml_w.writer.write(str::to_bytes(*name));
+        ebml_w.writer.write(name.as_bytes());
         ebml_w.end_tag();
         ebml_w.end_tag();
       }
@@ -1227,10 +1231,10 @@ fn encode_meta_item(ebml_w: &mut writer::Encoder, mi: @meta_item) {
           lit_str(value) => {
             ebml_w.start_tag(tag_meta_item_name_value);
             ebml_w.start_tag(tag_meta_item_name);
-            ebml_w.writer.write(str::to_bytes(*name));
+            ebml_w.writer.write(name.as_bytes());
             ebml_w.end_tag();
             ebml_w.start_tag(tag_meta_item_value);
-            ebml_w.writer.write(str::to_bytes(*value));
+            ebml_w.writer.write(value.as_bytes());
             ebml_w.end_tag();
             ebml_w.end_tag();
           }
@@ -1240,7 +1244,7 @@ fn encode_meta_item(ebml_w: &mut writer::Encoder, mi: @meta_item) {
       meta_list(name, ref items) => {
         ebml_w.start_tag(tag_meta_item_list);
         ebml_w.start_tag(tag_meta_item_name);
-        ebml_w.writer.write(str::to_bytes(*name));
+        ebml_w.writer.write(name.as_bytes());
         ebml_w.end_tag();
         for items.each |inner_item| {
             encode_meta_item(ebml_w, *inner_item);
@@ -1398,20 +1402,21 @@ fn encode_crate_dep(ecx: @EncodeContext,
                     dep: decoder::crate_dep) {
     ebml_w.start_tag(tag_crate_dep);
     ebml_w.start_tag(tag_crate_dep_name);
-    ebml_w.writer.write(str::to_bytes(*ecx.tcx.sess.str_of(dep.name)));
+    let s = ecx.tcx.sess.str_of(dep.name);
+    ebml_w.writer.write(s.as_bytes());
     ebml_w.end_tag();
     ebml_w.start_tag(tag_crate_dep_vers);
-    ebml_w.writer.write(str::to_bytes(*dep.vers));
+    ebml_w.writer.write(dep.vers.as_bytes());
     ebml_w.end_tag();
     ebml_w.start_tag(tag_crate_dep_hash);
-    ebml_w.writer.write(str::to_bytes(*dep.hash));
+    ebml_w.writer.write(dep.hash.as_bytes());
     ebml_w.end_tag();
     ebml_w.end_tag();
 }
 
 fn encode_hash(ebml_w: &mut writer::Encoder, hash: &str) {
     ebml_w.start_tag(tag_crate_hash);
-    ebml_w.writer.write(str::to_bytes(hash));
+    ebml_w.writer.write(hash.as_bytes());
     ebml_w.end_tag();
 }
 
@@ -1516,7 +1521,7 @@ pub fn encode_metadata(parms: EncodeParams, crate: &crate) -> ~[u8] {
 
     let writer_bytes: &mut ~[u8] = wr.bytes;
 
-    vec::to_owned(metadata_encoding_version) +
+    metadata_encoding_version.to_owned() +
         flate::deflate_bytes(*writer_bytes)
 }
 

src/librustc/metadata/filesearch.rs

@@ -13,7 +13,6 @@
 use core::option;
 use core::os;
 use core::result;
-use core::str;
 
 // A module for searching for libraries
 // FIXME (#2658): I'm not happy how this module turned out. Should
@@ -81,7 +80,7 @@ fn get_target_lib_file_path(&self, file: &Path) -> Path {
     @FileSearchImpl {
         sysroot: sysroot,
         addl_lib_search_paths: addl_lib_search_paths,
-        target_triple: str::to_owned(target_triple)
+        target_triple: target_triple.to_owned()
     } as @FileSearch
 }
 
@@ -107,7 +106,7 @@ pub fn search<T:Copy>(filesearch: @FileSearch, pick: pick<T>) -> Option<T> {
 
 pub fn relative_target_lib_path(target_triple: &str) -> Path {
     Path(libdir()).push_many([~"rustc",
-                              str::to_owned(target_triple),
+                              target_triple.to_owned(),
                               libdir()])
 }
 

src/librustc/metadata/loader.rs

@@ -80,7 +80,7 @@ fn libname(cx: &Context) -> (~str, ~str) {
         os_freebsd => (freebsd::DLL_PREFIX, freebsd::DLL_SUFFIX),
     };
 
-    (str::to_owned(dll_prefix), str::to_owned(dll_suffix))
+    (dll_prefix.to_owned(), dll_suffix.to_owned())
 }
 
 fn find_library_crate_aux(

src/librustc/middle/check_match.rs

@@ -495,7 +495,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                 match cx.tcx.def_map.find(&pat_id) {
                     Some(&def_variant(_, id)) => {
                         if variant(id) == *ctor_id {
-                            Some(vec::to_owned(r.tail()))
+                            Some(r.tail().to_owned())
                         } else {
                             None
                         }
@@ -533,7 +533,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                             _ => fail!("type error")
                         };
                         if match_ {
-                            Some(vec::to_owned(r.tail()))
+                            Some(r.tail().to_owned())
                         } else {
                             None
                         }
@@ -580,7 +580,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                             _ => fail!("type error")
                         };
                         if match_ {
-                            Some(vec::to_owned(r.tail()))
+                            Some(r.tail().to_owned())
                         } else {
                             None
                         }
@@ -590,7 +590,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                             Some(args) => args,
                             None => vec::from_elem(arity, wild())
                         };
-                        Some(vec::append(args, vec::to_owned(r.tail())))
+                        Some(vec::append(args, r.tail().to_owned()))
                     }
                     def_variant(_, _) => None,
 
@@ -602,7 +602,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                             Some(args) => new_args = args,
                             None => new_args = vec::from_elem(arity, wild())
                         }
-                        Some(vec::append(new_args, vec::to_owned(r.tail())))
+                        Some(vec::append(new_args, r.tail().to_owned()))
                     }
                     _ => None
                 }
@@ -620,7 +620,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                                     _ => wild()
                                 }
                             });
-                            Some(vec::append(args, vec::to_owned(r.tail())))
+                            Some(vec::append(args, r.tail().to_owned()))
                         } else {
                             None
                         }
@@ -651,7 +651,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                                 _ => wild()
                             }
                         });
-                        Some(vec::append(args, vec::to_owned(r.tail())))
+                        Some(vec::append(args, r.tail().to_owned()))
                     }
                 }
             }
@@ -687,14 +687,14 @@ pub fn specialize(cx: @MatchCheckCtxt,
                     single => true,
                     _ => fail!("type error")
                 };
-                if match_ { Some(vec::to_owned(r.tail())) } else { None }
+                if match_ { Some(r.tail().to_owned()) } else { None }
             }
             pat_range(lo, hi) => {
                 let (c_lo, c_hi) = match *ctor_id {
                     val(ref v) => ((/*bad*/copy *v), (/*bad*/copy *v)),
                     range(ref lo, ref hi) =>
                         ((/*bad*/copy *lo), (/*bad*/copy *hi)),
-                    single => return Some(vec::to_owned(r.tail())),
+                    single => return Some(r.tail().to_owned()),
                     _ => fail!("type error")
                 };
                 let v_lo = eval_const_expr(cx.tcx, lo);
@@ -704,7 +704,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                 let m2 = compare_const_vals(&c_hi, &v_hi);
                 match (m1, m2) {
                     (Some(val1), Some(val2)) if val1 >= 0 && val2 <= 0 => {
-                        Some(vec::to_owned(r.tail()))
+                        Some(r.tail().to_owned())
                     },
                     (Some(_), Some(_)) => None,
                     _ => {
@@ -745,7 +745,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
 }
 
 pub fn default(cx: @MatchCheckCtxt, r: &[@pat]) -> Option<~[@pat]> {
-    if is_wild(cx, r[0]) { Some(vec::to_owned(r.tail())) }
+    if is_wild(cx, r[0]) { Some(r.tail().to_owned()) }
     else { None }
 }
 

src/librustc/middle/lint.rs

@@ -23,7 +23,6 @@
 use core::i32;
 use core::i64;
 use core::i8;
-use core::str;
 use core::u16;
 use core::u32;
 use core::u64;
@@ -375,7 +374,7 @@ fn span_lint(&self, lint: lint, span: span, msg: &str) {
                 fmt!("%s [-%c %s%s]", msg, match level {
                         warn => 'W', deny => 'D', forbid => 'F',
                         allow => fail!()
-                    }, str::replace(self.lint_to_str(lint), "_", "-"),
+                    }, self.lint_to_str(lint).replace("_", "-"),
                     if src == Default { " (default)" } else { "" })
             },
             Node(src) => {
@@ -842,7 +841,7 @@ fn check_item_non_camel_case_types(cx: &Context, it: @ast::item) {
     fn is_camel_case(cx: ty::ctxt, ident: ast::ident) -> bool {
         let ident = cx.sess.str_of(ident);
         assert!(!ident.is_empty());
-        let ident = ident.trim_chars(&['_']);
+        let ident = ident.trim_chars(&'_');
         char::is_uppercase(ident.char_at(0)) &&
             !ident.contains_char('_')
     }

src/librustc/middle/resolve.rs

@@ -2678,14 +2678,14 @@ pub fn resolve_module_path(@mut self,
         match module_prefix_result {
             Failed => {
                 let mpath = self.idents_to_str(module_path);
-                match self.idents_to_str(module_path).rfind(':') {
+                match mpath.rfind(':') {
                     Some(idx) => {
                         self.session.span_err(span, fmt!("unresolved import: could not find `%s` \
-                                                         in `%s`", mpath.substr(idx,
-                                                                                mpath.len() - idx),
-                                                         // idx - 1 to account for the extra
-                                                         // colon
-                                                         mpath.substr(0, idx - 1)));
+                                                         in `%s`",
+                                                         // idx +- 1 to account for the colons
+                                                         // on either side
+                                                         mpath.slice_from(idx + 1),
+                                                         mpath.slice_to(idx - 1)));
                     },
                     None => (),
                 };

src/librustc/middle/trans/adt.rs

@@ -48,7 +48,6 @@
 use core::container::Map;
 use core::libc::c_ulonglong;
 use core::option::{Option, Some, None};
-use core::vec;
 
 use lib::llvm::{ValueRef, TypeRef, True, IntEQ, IntNE};
 use middle::trans::_match;
@@ -218,7 +217,7 @@ fn mk_struct(cx: @CrateContext, tys: &[ty::t], packed: bool) -> Struct {
         size: machine::llsize_of_alloc(cx, llty_rec) /*bad*/as u64,
         align: machine::llalign_of_min(cx, llty_rec) /*bad*/as u64,
         packed: packed,
-        fields: vec::to_owned(tys)
+        fields: tys.to_owned()
     }
 }
 

src/librustc/middle/trans/base.rs

@@ -114,7 +114,7 @@ impl get_insn_ctxt for @CrateContext {
     fn insn_ctxt(&self, s: &str) -> icx_popper {
         debug!("new insn_ctxt: %s", s);
         if self.sess.count_llvm_insns() {
-            self.stats.llvm_insn_ctxt.push(str::to_owned(s));
+            self.stats.llvm_insn_ctxt.push(s.to_owned());
         }
         icx_popper(*self)
     }

src/librustc/middle/trans/build.rs

@@ -885,9 +885,9 @@ pub fn add_comment(bcx: block, text: &str) {
     unsafe {
         let ccx = bcx.ccx();
         if ccx.sess.asm_comments() {
-            let sanitized = str::replace(text, "$", "");
+            let sanitized = text.replace("$", "");
             let comment_text = ~"# " +
-                str::replace(sanitized, "\n", "\n\t# ");
+                sanitized.replace("\n", "\n\t# ");
             let asm = str::as_c_str(comment_text, |c| {
                 str::as_c_str("", |e| {
                     count_insn(bcx, "inlineasm");

src/librustc/middle/trans/expr.rs

@@ -1704,5 +1704,5 @@ fn trans_assign_op(bcx: block,
 }
 
 fn shorten(x: ~str) -> ~str {
-    if x.len() > 60 { x.substr(0, 60).to_owned() } else { x }
+    if x.char_len() > 60 { x.slice_chars(0, 60).to_owned() } else { x }
 }

src/librustc/middle/ty.rs

@@ -3898,7 +3898,7 @@ pub fn item_path(cx: ctxt, id: ast::def_id) -> ast_map::path {
           }
 
           ast_map::node_variant(ref variant, _, path) => {
-            vec::append_one(vec::to_owned(vec::init(*path)),
+            vec::append_one(path.init().to_owned(),
                             ast_map::path_name((*variant).node.name))
           }
 

src/librustc/rustc.rc

@@ -209,7 +209,7 @@ Available lint options:
     io::println(fmt!("    %s  %7.7s  %s\n",
                      padded(max_key, "----"), "-------", "-------"));
     for lint_dict.each |k, v| {
-        let k = str::replace(*k, "_", "-");
+        let k = k.replace("_", "-");
         io::println(fmt!("    %s  %7.7s  %s",
                          padded(max_key, k),
                          match v.default {

src/librustdoc/attr_parser.rs

@@ -17,7 +17,6 @@
 
 use core::prelude::*;
 
-use core::str;
 use syntax::ast;
 use syntax::attr;
 

src/librustdoc/config.rs

@@ -262,7 +262,7 @@ fn should_find_pandoc() {
             .. default_config(&Path("test"))
         };
         let mock_process_output: ~fn(&str, &[~str]) -> ProcessOutput = |_, _| {
-            ProcessOutput { status: 0, output: "pandoc 1.8.2.1".to_bytes(), error: ~[] }
+            ProcessOutput { status: 0, output: "pandoc 1.8.2.1".as_bytes().to_owned(), error: ~[] }
         };
         let result = maybe_find_pandoc(&config, None, mock_process_output);
         assert!(result == result::Ok(Some(~"pandoc")));

src/librustdoc/desc_to_brief_pass.rs

@@ -108,7 +108,7 @@ fn first_sentence(s: ~str) -> Option<~str> {
     let paras = paragraphs(s);
     if !paras.is_empty() {
         let first_para = paras.head();
-        Some(str::replace(first_sentence_(*first_para), "\n", " "))
+        Some(first_sentence_(*first_para).replace("\n", " "))
     } else {
         None
     }
@@ -131,13 +131,13 @@ fn first_sentence_(s: &str) -> ~str {
     });
     match idx {
         Some(idx) if idx > 2u => {
-            str::to_owned(s.slice(0, idx - 1))
+            s.slice_to(idx - 1).to_owned()
         }
         _ => {
             if s.ends_with(".") {
-                str::to_owned(s)
+                s.to_owned()
             } else {
-                str::to_owned(s)
+                s.to_owned()
             }
         }
     }

src/librustdoc/escape_pass.rs

@@ -13,14 +13,12 @@
 use pass::Pass;
 use text_pass;
 
-use core::str;
-
 pub fn mk_pass() -> Pass {
     text_pass::mk_pass(~"escape", escape)
 }
 
 fn escape(s: &str) -> ~str {
-    str::replace(s, "\\", "\\\\")
+    s.replace("\\", "\\\\")
 }
 
 #[test]

src/librustdoc/markdown_index_pass.rs

@@ -22,8 +22,6 @@
 use markdown_writer;
 use pass::Pass;
 
-use core::str;
-
 pub fn mk_pass(config: config::Config) -> Pass {
     Pass {
         name: ~"markdown_index",
@@ -128,24 +126,24 @@ pub fn pandoc_header_id(header: &str) -> ~str {
     return header;
 
     fn remove_formatting(s: &str) -> ~str {
-        str::replace(s, "`", "")
+        s.replace("`", "")
     }
     fn remove_punctuation(s: &str) -> ~str {
-        let s = str::replace(s, "<", "");
-        let s = str::replace(s, ">", "");
-        let s = str::replace(s, "[", "");
-        let s = str::replace(s, "]", "");
-        let s = str::replace(s, "(", "");
-        let s = str::replace(s, ")", "");
-        let s = str::replace(s, "@~", "");
-        let s = str::replace(s, "~", "");
-        let s = str::replace(s, "/", "");
-        let s = str::replace(s, ":", "");
-        let s = str::replace(s, "&", "");
-        let s = str::replace(s, "^", "");
-        let s = str::replace(s, ",", "");
-        let s = str::replace(s, "'", "");
-        let s = str::replace(s, "+", "");
+        let s = s.replace("<", "");
+        let s = s.replace(">", "");
+        let s = s.replace("[", "");
+        let s = s.replace("]", "");
+        let s = s.replace("(", "");
+        let s = s.replace(")", "");
+        let s = s.replace("@~", "");
+        let s = s.replace("~", "");
+        let s = s.replace("/", "");
+        let s = s.replace(":", "");
+        let s = s.replace("&", "");
+        let s = s.replace("^", "");
+        let s = s.replace(",", "");
+        let s = s.replace("'", "");
+        let s = s.replace("+", "");
         return s;
     }
     fn replace_with_hyphens(s: &str) -> ~str {
@@ -153,8 +151,8 @@ fn replace_with_hyphens(s: &str) -> ~str {
         // XXX: Hacky implementation here that only covers
         // one or two spaces.
         let s = s.trim();
-        let s = str::replace(s, "  ", "-");
-        let s = str::replace(s, " ", "-");
+        let s = s.replace("  ", "-");
+        let s = s.replace(" ", "-");
         return s;
     }
     // FIXME: #4318 Instead of to_ascii and to_str_ascii, could use

src/librustdoc/markdown_pass.rs

@@ -114,7 +114,7 @@ fn make_title(page: doc::Page) -> ~str {
         }
     };
     let title = markdown_pass::header_text(item);
-    let title = str::replace(title, "`", "");
+    let title = title.replace("`", "");
     return title;
 }
 

src/librusti/rusti.rc

@@ -284,7 +284,7 @@ fn run_cmd(repl: &mut Repl, _in: @io::Reader, _out: @io::Writer,
             for args.each |arg| {
                 let (crate, filename) =
                     if arg.ends_with(".rs") || arg.ends_with(".rc") {
-                    (arg.substr(0, arg.len() - 3).to_owned(), copy *arg)
+                    (arg.slice_to(arg.len() - 3).to_owned(), copy *arg)
                 } else {
                     (copy *arg, arg + ".rs")
                 };
@@ -342,7 +342,8 @@ pub fn run_line(repl: &mut Repl, in: @io::Reader, out: @io::Writer, line: ~str,
         // FIXME #5898: conflicts with Cell.take(), so can't be at the top level
         use core::iterator::IteratorUtil;
 
-        let full = line.substr(1, line.len() - 1);
+        // drop the : and the \n (one byte each)
+        let full = line.slice(1, line.len() - 1);
         let split: ~[~str] = full.word_iter().transform(|s| s.to_owned()).collect();
         let len = split.len();
 

src/librustpkg/package_path.rs

@@ -12,7 +12,7 @@
 
 use core::path::Path;
 use core::option::Some;
-use core::{hash, str};
+use core::hash;
 use core::rt::io::Writer;
 use core::hash::Streaming;
 
@@ -32,7 +32,7 @@ pub fn normalize(p_: RemotePath) -> LocalPath {
     match p.filestem() {
         None => LocalPath(p),
         Some(st) => {
-            let replaced = str::replace(st, "-", "_");
+            let replaced = st.replace("-", "_");
             if replaced != st {
                 LocalPath(p.with_filestem(replaced))
             }
@@ -44,8 +44,7 @@ pub fn normalize(p_: RemotePath) -> LocalPath {
 }
 
 pub fn write<W: Writer>(writer: &mut W, string: &str) {
-    let buffer = str::as_bytes_slice(string);
-    writer.write(buffer);
+    writer.write(string.as_bytes());
 }
 
 pub fn hash(data: ~str) -> ~str {

src/librustpkg/package_source.rs

@@ -183,7 +183,7 @@ pub fn find_crates(&mut self) {
         if self.libs.is_empty() && self.mains.is_empty()
             && self.tests.is_empty() && self.benchs.is_empty() {
 
-            note(~"Couldn't infer any crates to build.\n\
+            note("Couldn't infer any crates to build.\n\
                          Try naming a crate `main.rs`, `lib.rs`, \
                          `test.rs`, or `bench.rs`.");
             cond.raise(copy self.id);

src/libstd/hashmap.rs

@@ -866,6 +866,23 @@ fn test_expand() {
         assert_eq!(m.len(), i);
         assert!(!m.is_empty());
     }
+
+    #[test]
+    fn test_find_equiv() {
+        let mut m = HashMap::new();
+
+        let (foo, bar, baz) = (1,2,3);
+        m.insert(~"foo", foo);
+        m.insert(~"bar", bar);
+        m.insert(~"baz", baz);
+
+
+        assert_eq!(m.find_equiv(&("foo")), Some(&foo));
+        assert_eq!(m.find_equiv(&("bar")), Some(&bar));
+        assert_eq!(m.find_equiv(&("baz")), Some(&baz));
+
+        assert_eq!(m.find_equiv(&("qux")), None);
+    }
 }
 
 #[cfg(test)]

src/libstd/io.rs

@@ -761,7 +761,7 @@ fn each_line(&self, it: &fn(s: &str) -> bool) -> bool {
     fn read_lines(&self) -> ~[~str] {
         do vec::build |push| {
             for self.each_line |line| {
-                push(str::to_owned(line));
+                push(line.to_owned());
             }
         }
     }
@@ -1091,7 +1091,7 @@ pub fn with_bytes_reader<T>(bytes: &[u8], f: &fn(@Reader) -> T) -> T {
 }
 
 pub fn with_str_reader<T>(s: &str, f: &fn(@Reader) -> T) -> T {
-    str::byte_slice(s, |bytes| with_bytes_reader(bytes, f))
+    with_bytes_reader(s.as_bytes(), f)
 }
 
 // Writing
@@ -1462,7 +1462,7 @@ fn write_char(&self, ch: char) {
             self.write_str(str::from_char(ch));
         }
     }
-    fn write_str(&self, s: &str) { str::byte_slice(s, |v| self.write(v)) }
+    fn write_str(&self, s: &str) { self.write(s.as_bytes()) }
     fn write_line(&self, s: &str) {
         self.write_str(s);
         self.write_str(&"\n");

src/libstd/num/int_macros.rs

@@ -793,27 +793,27 @@ fn test_from_str() {
 
     #[test]
     fn test_parse_bytes() {
-        use str::to_bytes;
-        assert_eq!(parse_bytes(to_bytes("123"), 10u), Some(123 as $T));
-        assert_eq!(parse_bytes(to_bytes("1001"), 2u), Some(9 as $T));
-        assert_eq!(parse_bytes(to_bytes("123"), 8u), Some(83 as $T));
-        assert_eq!(i32::parse_bytes(to_bytes("123"), 16u), Some(291 as i32));
-        assert_eq!(i32::parse_bytes(to_bytes("ffff"), 16u), Some(65535 as i32));
-        assert_eq!(i32::parse_bytes(to_bytes("FFFF"), 16u), Some(65535 as i32));
-        assert_eq!(parse_bytes(to_bytes("z"), 36u), Some(35 as $T));
-        assert_eq!(parse_bytes(to_bytes("Z"), 36u), Some(35 as $T));
+        use str::StrSlice;
+        assert_eq!(parse_bytes("123".as_bytes(), 10u), Some(123 as $T));
+        assert_eq!(parse_bytes("1001".as_bytes(), 2u), Some(9 as $T));
+        assert_eq!(parse_bytes("123".as_bytes(), 8u), Some(83 as $T));
+        assert_eq!(i32::parse_bytes("123".as_bytes(), 16u), Some(291 as i32));
+        assert_eq!(i32::parse_bytes("ffff".as_bytes(), 16u), Some(65535 as i32));
+        assert_eq!(i32::parse_bytes("FFFF".as_bytes(), 16u), Some(65535 as i32));
+        assert_eq!(parse_bytes("z".as_bytes(), 36u), Some(35 as $T));
+        assert_eq!(parse_bytes("Z".as_bytes(), 36u), Some(35 as $T));
 
-        assert_eq!(parse_bytes(to_bytes("-123"), 10u), Some(-123 as $T));
-        assert_eq!(parse_bytes(to_bytes("-1001"), 2u), Some(-9 as $T));
-        assert_eq!(parse_bytes(to_bytes("-123"), 8u), Some(-83 as $T));
-        assert_eq!(i32::parse_bytes(to_bytes("-123"), 16u), Some(-291 as i32));
-        assert_eq!(i32::parse_bytes(to_bytes("-ffff"), 16u), Some(-65535 as i32));
-        assert_eq!(i32::parse_bytes(to_bytes("-FFFF"), 16u), Some(-65535 as i32));
-        assert_eq!(parse_bytes(to_bytes("-z"), 36u), Some(-35 as $T));
-        assert_eq!(parse_bytes(to_bytes("-Z"), 36u), Some(-35 as $T));
+        assert_eq!(parse_bytes("-123".as_bytes(), 10u), Some(-123 as $T));
+        assert_eq!(parse_bytes("-1001".as_bytes(), 2u), Some(-9 as $T));
+        assert_eq!(parse_bytes("-123".as_bytes(), 8u), Some(-83 as $T));
+        assert_eq!(i32::parse_bytes("-123".as_bytes(), 16u), Some(-291 as i32));
+        assert_eq!(i32::parse_bytes("-ffff".as_bytes(), 16u), Some(-65535 as i32));
+        assert_eq!(i32::parse_bytes("-FFFF".as_bytes(), 16u), Some(-65535 as i32));
+        assert_eq!(parse_bytes("-z".as_bytes(), 36u), Some(-35 as $T));
+        assert_eq!(parse_bytes("-Z".as_bytes(), 36u), Some(-35 as $T));
 
-        assert!(parse_bytes(to_bytes("Z"), 35u).is_none());
-        assert!(parse_bytes(to_bytes("-9"), 2u).is_none());
+        assert!(parse_bytes("Z".as_bytes(), 35u).is_none());
+        assert!(parse_bytes("-9".as_bytes(), 2u).is_none());
     }
 
     #[test]

src/libstd/num/strconv.rs

@@ -16,6 +16,7 @@
 use option::{None, Option, Some};
 use char;
 use str;
+use str::{StrSlice};
 use kinds::Copy;
 use vec;
 use vec::{CopyableVector, ImmutableVector};
@@ -189,18 +190,18 @@ pub fn to_str_bytes_common<T:NumCast+Zero+One+Eq+Ord+NumStrConv+Copy+
     let _1: T = One::one();
 
     if is_NaN(num) {
-        return (str::to_bytes("NaN"), true);
+        return ("NaN".as_bytes().to_owned(), true);
     }
     else if is_inf(num){
         return match sign {
-            SignAll => (str::to_bytes("+inf"), true),
-            _       => (str::to_bytes("inf"), true)
+            SignAll => ("+inf".as_bytes().to_owned(), true),
+            _       => ("inf".as_bytes().to_owned(), true)
         }
     }
     else if is_neg_inf(num) {
         return match sign {
-            SignNone => (str::to_bytes("inf"), true),
-            _        => (str::to_bytes("-inf"), true),
+            SignNone => ("inf".as_bytes().to_owned(), true),
+            _        => ("-inf".as_bytes().to_owned(), true),
         }
     }
 
@@ -638,7 +639,7 @@ pub fn from_str_common<T:NumCast+Zero+One+Eq+Ord+Copy+Div<T,T>+Mul<T,T>+
         special: bool, exponent: ExponentFormat, empty_zero: bool,
         ignore_underscores: bool
         ) -> Option<T> {
-    from_str_bytes_common(str::to_bytes(buf), radix, negative,
+    from_str_bytes_common(buf.as_bytes(), radix, negative,
                           fractional, special, exponent, empty_zero,
                           ignore_underscores)
 }

src/libstd/num/uint_macros.rs

@@ -538,16 +538,16 @@ pub fn test_from_str() {
 
     #[test]
     pub fn test_parse_bytes() {
-        use str::to_bytes;
-        assert_eq!(parse_bytes(to_bytes("123"), 10u), Some(123u as $T));
-        assert_eq!(parse_bytes(to_bytes("1001"), 2u), Some(9u as $T));
-        assert_eq!(parse_bytes(to_bytes("123"), 8u), Some(83u as $T));
-        assert_eq!(u16::parse_bytes(to_bytes("123"), 16u), Some(291u as u16));
-        assert_eq!(u16::parse_bytes(to_bytes("ffff"), 16u), Some(65535u as u16));
-        assert_eq!(parse_bytes(to_bytes("z"), 36u), Some(35u as $T));
+        use str::StrSlice;
+        assert_eq!(parse_bytes("123".as_bytes(), 10u), Some(123u as $T));
+        assert_eq!(parse_bytes("1001".as_bytes(), 2u), Some(9u as $T));
+        assert_eq!(parse_bytes("123".as_bytes(), 8u), Some(83u as $T));
+        assert_eq!(u16::parse_bytes("123".as_bytes(), 16u), Some(291u as u16));
+        assert_eq!(u16::parse_bytes("ffff".as_bytes(), 16u), Some(65535u as u16));
+        assert_eq!(parse_bytes("z".as_bytes(), 36u), Some(35u as $T));
 
-        assert!(parse_bytes(to_bytes("Z"), 10u).is_none());
-        assert!(parse_bytes(to_bytes("_"), 2u).is_none());
+        assert!(parse_bytes("Z".as_bytes(), 10u).is_none());
+        assert!(parse_bytes("_".as_bytes(), 2u).is_none());
     }
 
     #[test]

src/libstd/os.rs

@@ -1448,9 +1448,9 @@ mod tests {
     use rand::RngUtil;
     use rand;
     use run;
-    use str;
     use str::StrSlice;
     use vec;
+    use vec::CopyableVector;
     use libc::consts::os::posix88::{S_IRUSR, S_IWUSR, S_IXUSR};
 
 
@@ -1684,7 +1684,7 @@ fn copy_file_ok() {
           };
           assert!((ostream as uint != 0u));
           let s = ~"hello";
-          let mut buf = str::to_bytes(s) + [0 as u8];
+          let mut buf = s.as_bytes_with_null().to_owned();
           do vec::as_mut_buf(buf) |b, _len| {
               assert!((libc::fwrite(b as *c_void, 1u as size_t,
                                    (s.len() + 1u) as size_t, ostream)

src/libstd/path.rs

@@ -515,7 +515,7 @@ fn with_filename(&self, f: &str) -> PosixPath {
     fn with_filestem(&self, s: &str) -> PosixPath {
         match self.filetype() {
             None => self.with_filename(s),
-            Some(ref t) => self.with_filename(str::to_owned(s) + *t),
+            Some(ref t) => self.with_filename(s.to_owned() + *t),
         }
     }
 
@@ -657,7 +657,7 @@ fn from_str(s: &str) -> WindowsPath {
             (None, None) => {
                 host = None;
                 device = None;
-                rest = str::to_owned(s);
+                rest = s.to_owned();
             }
         }
 
@@ -729,7 +729,7 @@ fn with_filename(&self, f: &str) -> WindowsPath {
     fn with_filestem(&self, s: &str) -> WindowsPath {
         match self.filetype() {
             None => self.with_filename(s),
-            Some(ref t) => self.with_filename(str::to_owned(s) + *t),
+            Some(ref t) => self.with_filename(s.to_owned() + *t),
         }
     }
 
@@ -947,7 +947,6 @@ pub fn extract_drive_prefix(s: &str) -> Option<(~str,~str)> {
 mod tests {
     use option::{None, Some};
     use path::{PosixPath, WindowsPath, windows};
-    use str;
 
     #[test]
     fn test_double_slash_collapsing() {
@@ -984,7 +983,7 @@ fn test_filetype_foo() {
     fn test_posix_paths() {
         fn t(wp: &PosixPath, s: &str) {
             let ss = wp.to_str();
-            let sss = str::to_owned(s);
+            let sss = s.to_owned();
             if (ss != sss) {
                 debug!("got %s", ss);
                 debug!("expected %s", sss);
@@ -1042,7 +1041,7 @@ fn t(wp: &PosixPath, s: &str) {
     fn test_normalize() {
         fn t(wp: &PosixPath, s: &str) {
             let ss = wp.to_str();
-            let sss = str::to_owned(s);
+            let sss = s.to_owned();
             if (ss != sss) {
                 debug!("got %s", ss);
                 debug!("expected %s", sss);
@@ -1105,7 +1104,7 @@ fn test_extract_drive_prefixes() {
     fn test_windows_paths() {
         fn t(wp: &WindowsPath, s: &str) {
             let ss = wp.to_str();
-            let sss = str::to_owned(s);
+            let sss = s.to_owned();
             if (ss != sss) {
                 debug!("got %s", ss);
                 debug!("expected %s", sss);

src/libstd/prelude.rs

@@ -64,7 +64,7 @@
 pub use path::WindowsPath;
 pub use ptr::RawPtr;
 pub use ascii::{Ascii, AsciiCast, OwnedAsciiCast, AsciiStr};
-pub use str::{StrVector, StrSlice, OwnedStr, StrUtil};
+pub use str::{StrVector, StrSlice, OwnedStr, StrUtil, NullTerminatedStr};
 pub use from_str::{FromStr};
 pub use to_bytes::IterBytes;
 pub use to_str::{ToStr, ToStrConsume};

src/libstd/rand.rs

@@ -577,7 +577,7 @@ fn weighted_vec<T:Copy>(&mut self, v: &[Weighted<T>]) -> ~[T] {
 
     /// Shuffle a vec
     fn shuffle<T:Copy>(&mut self, values: &[T]) -> ~[T] {
-        let mut m = vec::to_owned(values);
+        let mut m = values.to_owned();
         self.shuffle_mut(m);
         m
     }

src/libstd/rt/io/file.rs

@@ -75,5 +75,5 @@ fn super_simple_smoke_test_lets_go_read_some_files_and_have_a_good_time() {
     let message = "it's alright. have a good time";
     let filename = &Path("test.txt");
     let mut outstream = FileStream::open(filename, Create, Read).unwrap();
-    outstream.write(message.to_bytes());
+    outstream.write(message.as_bytes());
 }

src/libstd/rt/io/flate.rs

@@ -108,7 +108,7 @@ fn smoke_test() {
         let mem_writer = MemWriter::new();
         let mut deflate_writer = DeflateWriter::new(mem_writer);
         let in_msg = "test";
-        let in_bytes = in_msg.to_bytes();
+        let in_bytes = in_msg.as_bytes();
         deflate_writer.write(in_bytes);
         deflate_writer.flush();
         let buf = deflate_writer.inner().inner();

src/libstd/run.rs

@@ -741,8 +741,7 @@ fn with_envp<T>(env: Option<&[(~str, ~str)]>, cb: &fn(*mut c_void) -> T) -> T {
         let mut blk = ~[];
         for es.each |&(k, v)| {
             let kv = fmt!("%s=%s", k, v);
-            blk.push_all(str::as_bytes_slice(kv));
-            blk.push(0);
+            blk.push_all(kv.as_bytes_with_null_consume());
         }
         blk.push(0);
         vec::as_imm_buf(blk, |p, _len|

src/libstd/str.rs

@@ -26,7 +26,7 @@
 use cmp::{TotalOrd, Ordering, Less, Equal, Greater};
 use container::Container;
 use iter::Times;
-use iterator::{Iterator, IteratorUtil, FilterIterator};
+use iterator::{Iterator, IteratorUtil, FilterIterator, AdditiveIterator};
 use libc;
 use option::{None, Option, Some};
 use old_iter::{BaseIter, EqIter};
@@ -107,23 +107,17 @@ pub fn from_bytes_slice<'a>(vector: &'a [u8]) -> &'a str {
     }
 }
 
-/// Copy a slice into a new unique str
-#[inline(always)]
-pub fn to_owned(s: &str) -> ~str {
-    unsafe { raw::slice_bytes_owned(s, 0, s.len()) }
-}
-
 impl ToStr for ~str {
     #[inline(always)]
-    fn to_str(&self) -> ~str { to_owned(*self) }
+    fn to_str(&self) -> ~str { self.to_owned() }
 }
 impl<'self> ToStr for &'self str {
     #[inline(always)]
-    fn to_str(&self) -> ~str { to_owned(*self) }
+    fn to_str(&self) -> ~str { self.to_owned() }
 }
 impl ToStr for @str {
     #[inline(always)]
-    fn to_str(&self) -> ~str { to_owned(*self) }
+    fn to_str(&self) -> ~str { self.to_owned() }
 }
 
 /**
@@ -160,29 +154,19 @@ pub fn push_str(lhs: &mut ~str, rhs: &str) {
     lhs.push_str(rhs)
 }
 
-/// Concatenate two strings together
-#[inline(always)]
-pub fn append(lhs: ~str, rhs: &str) -> ~str {
-    let mut v = lhs;
-    v.push_str_no_overallocate(rhs);
-    v
-}
-
 #[allow(missing_doc)]
 pub trait StrVector {
     pub fn concat(&self) -> ~str;
     pub fn connect(&self, sep: &str) -> ~str;
 }
 
-impl<'self> StrVector for &'self [~str] {
+impl<'self, S: Str> StrVector for &'self [S] {
     /// Concatenate a vector of strings.
     pub fn concat(&self) -> ~str {
         if self.is_empty() { return ~""; }
 
-        let mut len = 0;
-        for self.each |ss| {
-            len += ss.len();
-        }
+        let len = self.iter().transform(|s| s.as_slice().len()).sum();
+
         let mut s = ~"";
 
         s.reserve(len);
@@ -190,8 +174,8 @@ pub fn concat(&self) -> ~str {
         unsafe {
             do as_buf(s) |buf, _| {
                 let mut buf = ::cast::transmute_mut_unsafe(buf);
-                for self.each |ss| {
-                    do as_buf(*ss) |ssbuf, sslen| {
+                for self.iter().advance |ss| {
+                    do as_buf(ss.as_slice()) |ssbuf, sslen| {
                         let sslen = sslen - 1;
                         ptr::copy_memory(buf, ssbuf, sslen);
                         buf = buf.offset(sslen);
@@ -211,10 +195,8 @@ pub fn connect(&self, sep: &str) -> ~str {
         if sep.is_empty() { return self.concat(); }
 
         // this is wrong without the guarantee that `self` is non-empty
-        let mut len = sep.len() * (self.len() - 1);
-        for self.each |ss| {
-            len += ss.len();
-        }
+        let len = sep.len() * (self.len() - 1)
+            + self.iter().transform(|s| s.as_slice().len()).sum();
         let mut s = ~"";
         let mut first = true;
 
@@ -225,8 +207,8 @@ pub fn connect(&self, sep: &str) -> ~str {
                 do as_buf(sep) |sepbuf, seplen| {
                     let seplen = seplen - 1;
                     let mut buf = ::cast::transmute_mut_unsafe(buf);
-                    for self.each |ss| {
-                        do as_buf(*ss) |ssbuf, sslen| {
+                    for self.iter().advance |ss| {
+                        do as_buf(ss.as_slice()) |ssbuf, sslen| {
                             let sslen = sslen - 1;
                             if first {
                                 first = false;
@@ -246,192 +228,6 @@ pub fn connect(&self, sep: &str) -> ~str {
     }
 }
 
-impl<'self> StrVector for &'self [&'self str] {
-    /// Concatenate a vector of strings.
-    pub fn concat(&self) -> ~str {
-        if self.is_empty() { return ~""; }
-
-        let mut len = 0;
-        for self.each |ss| {
-            len += ss.len();
-        }
-        let mut s = ~"";
-
-        s.reserve(len);
-
-        unsafe {
-            do as_buf(s) |buf, _| {
-                let mut buf = ::cast::transmute_mut_unsafe(buf);
-                for self.each |ss| {
-                    do as_buf(*ss) |ssbuf, sslen| {
-                        let sslen = sslen - 1;
-                        ptr::copy_memory(buf, ssbuf, sslen);
-                        buf = buf.offset(sslen);
-                    }
-                }
-            }
-            raw::set_len(&mut s, len);
-        }
-        s
-    }
-
-    /// Concatenate a vector of strings, placing a given separator between each.
-    pub fn connect(&self, sep: &str) -> ~str {
-        if self.is_empty() { return ~""; }
-
-        // concat is faster
-        if sep.is_empty() { return self.concat(); }
-
-        // this is wrong without the guarantee that `self` is non-empty
-        let mut len = sep.len() * (self.len() - 1);
-        for self.each |ss| {
-            len += ss.len();
-        }
-        let mut s = ~"";
-        let mut first = true;
-
-        s.reserve(len);
-
-        unsafe {
-            do as_buf(s) |buf, _| {
-                do as_buf(sep) |sepbuf, seplen| {
-                    let seplen = seplen - 1;
-                    let mut buf = ::cast::transmute_mut_unsafe(buf);
-                    for self.each |ss| {
-                        do as_buf(*ss) |ssbuf, sslen| {
-                            let sslen = sslen - 1;
-                            if first {
-                                first = false;
-                            } else {
-                                ptr::copy_memory(buf, sepbuf, seplen);
-                                buf = buf.offset(seplen);
-                            }
-                            ptr::copy_memory(buf, ssbuf, sslen);
-                            buf = buf.offset(sslen);
-                        }
-                    }
-                }
-            }
-            raw::set_len(&mut s, len);
-        }
-        s
-    }
-}
-
-/// Given a string, make a new string with repeated copies of it
-pub fn repeat(ss: &str, nn: uint) -> ~str {
-    do as_buf(ss) |buf, len| {
-        let mut ret = ~"";
-        // ignore the NULL terminator
-        let len = len - 1;
-        ret.reserve(nn * len);
-
-        unsafe {
-            do as_buf(ret) |rbuf, _len| {
-                let mut rbuf = ::cast::transmute_mut_unsafe(rbuf);
-
-                for nn.times {
-                    ptr::copy_memory(rbuf, buf, len);
-                    rbuf = rbuf.offset(len);
-                }
-            }
-            raw::set_len(&mut ret, nn * len);
-        }
-        ret
-    }
-}
-
-/*
-Section: Adding to and removing from a string
-*/
-
-/**
- * Remove the final character from a string and return it
- *
- * # Failure
- *
- * If the string does not contain any characters
- */
-pub fn pop_char(s: &mut ~str) -> char {
-    let end = s.len();
-    assert!(end > 0u);
-    let CharRange {ch, next} = s.char_range_at_reverse(end);
-    unsafe { raw::set_len(s, next); }
-    return ch;
-}
-
-/**
- * Remove the first character from a string and return it
- *
- * # Failure
- *
- * If the string does not contain any characters
- */
-pub fn shift_char(s: &mut ~str) -> char {
-    let CharRange {ch, next} = s.char_range_at(0u);
-    *s = unsafe { raw::slice_bytes_owned(*s, next, s.len()) };
-    return ch;
-}
-
-/**
- * Removes the first character from a string slice and returns it. This does
- * not allocate a new string; instead, it mutates a slice to point one
- * character beyond the character that was shifted.
- *
- * # Failure
- *
- * If the string does not contain any characters
- */
-#[inline]
-pub fn slice_shift_char<'a>(s: &'a str) -> (char, &'a str) {
-    let CharRange {ch, next} = s.char_range_at(0u);
-    let next_s = unsafe { raw::slice_bytes(s, next, s.len()) };
-    return (ch, next_s);
-}
-
-/// Prepend a char to a string
-pub fn unshift_char(s: &mut ~str, ch: char) {
-    // This could be more efficient.
-    let mut new_str = ~"";
-    new_str.push_char(ch);
-    new_str.push_str(*s);
-    *s = new_str;
-}
-
-/*
-Section: Transforming strings
-*/
-
-/**
- * Converts a string to a unique vector of bytes
- *
- * The result vector is not null-terminated.
- */
-pub fn to_bytes(s: &str) -> ~[u8] {
-    unsafe {
-        let mut v: ~[u8] = ::cast::transmute(to_owned(s));
-        vec::raw::set_len(&mut v, s.len());
-        v
-    }
-}
-
-/// Work with the string as a byte slice, not including trailing null.
-#[inline(always)]
-pub fn byte_slice<T>(s: &str, f: &fn(v: &[u8]) -> T) -> T {
-    do as_buf(s) |p,n| {
-        unsafe { vec::raw::buf_as_slice(p, n-1u, f) }
-    }
-}
-
-/// Work with the string as a byte slice, not including trailing null, without
-/// a callback.
-#[inline(always)]
-pub fn byte_slice_no_callback<'a>(s: &'a str) -> &'a [u8] {
-    unsafe {
-        cast::transmute(s)
-    }
-}
-
 /// Something that can be used to compare against a character
 pub trait CharEq {
     /// Determine if the splitter should split at the given character
@@ -459,6 +255,17 @@ fn matches(&self, c: char) -> bool { (*self)(c) }
     fn only_ascii(&self) -> bool { false }
 }
 
+impl<'self, C: CharEq> CharEq for &'self [C] {
+    #[inline(always)]
+    fn matches(&self, c: char) -> bool {
+        self.iter().any_(|m| m.matches(c))
+    }
+
+    fn only_ascii(&self) -> bool {
+        self.iter().all(|m| m.only_ascii())
+    }
+}
+
 
 /// An iterator over the substrings of a string, separated by `sep`.
 pub struct StrCharSplitIterator<'self,Sep> {
@@ -709,30 +516,6 @@ enum LengthLimit {
     return cont;
 }
 
-/**
- * Replace all occurrences of one string with another
- *
- * # Arguments
- *
- * * s - The string containing substrings to replace
- * * from - The string to replace
- * * to - The replacement string
- *
- * # Return value
- *
- * The original string with all occurances of `from` replaced with `to`
- */
-pub fn replace(s: &str, from: &str, to: &str) -> ~str {
-    let mut (result, last_end) = (~"", 0);
-    for s.matches_index_iter(from).advance |(start, end)| {
-        result.push_str(unsafe{raw::slice_bytes(s, last_end, start)});
-        result.push_str(to);
-        last_end = end;
-    }
-    result.push_str(unsafe{raw::slice_bytes(s, last_end, s.len())});
-    result
-}
-
 /*
 Section: Comparing strings
 */
@@ -976,15 +759,6 @@ fn match_at<'a,'b>(haystack: &'a str, needle: &'b str, at: uint) -> bool {
     return true;
 }
 
-
-/*
-Section: String properties
-*/
-
-/// Returns the number of characters that a string holds
-#[inline(always)]
-pub fn char_len(s: &str) -> uint { count_chars(s, 0u, s.len()) }
-
 /*
 Section: Misc
 */
@@ -1102,46 +876,6 @@ pub fn with_capacity(capacity: uint) -> ~str {
     buf
 }
 
-/**
- * As char_len but for a slice of a string
- *
- * # Arguments
- *
- * * s - A valid string
- * * start - The position inside `s` where to start counting in bytes
- * * end - The position where to stop counting
- *
- * # Return value
- *
- * The number of Unicode characters in `s` between the given indices.
- */
-pub fn count_chars(s: &str, start: uint, end: uint) -> uint {
-    assert!(s.is_char_boundary(start));
-    assert!(s.is_char_boundary(end));
-    let mut (i, len) = (start, 0u);
-    while i < end {
-        let next = s.char_range_at(i).next;
-        len += 1u;
-        i = next;
-    }
-    return len;
-}
-
-/// Counts the number of bytes taken by the first `n` chars in `s`
-/// starting from `start`.
-pub fn count_bytes<'b>(s: &'b str, start: uint, n: uint) -> uint {
-    assert!(s.is_char_boundary(start));
-    let mut (end, cnt) = (start, n);
-    let l = s.len();
-    while cnt > 0u {
-        assert!(end < l);
-        let next = s.char_range_at(end).next;
-        cnt -= 1u;
-        end = next;
-    }
-    end - start
-}
-
 /// Given a first byte, determine how many bytes are in this UTF-8 character
 pub fn utf8_char_width(b: u8) -> uint {
     let byte: uint = b as uint;
@@ -1175,39 +909,6 @@ pub struct CharRange {
 static max_five_b: uint = 67108864u;
 static tag_six_b: uint = 252u;
 
-/**
- * Work with the byte buffer of a string.
- *
- * Allows for unsafe manipulation of strings, which is useful for foreign
- * interop.
- *
- * # Example
- *
- * ~~~ {.rust}
- * let i = str::as_bytes("Hello World") { |bytes| bytes.len() };
- * ~~~
- */
-#[inline]
-pub fn as_bytes<T>(s: &const ~str, f: &fn(&~[u8]) -> T) -> T {
-    unsafe {
-        let v: *~[u8] = cast::transmute(copy s);
-        f(&*v)
-    }
-}
-
-/**
- * Work with the byte buffer of a string as a byte slice.
- *
- * The byte slice does not include the null terminator.
- */
-pub fn as_bytes_slice<'a>(s: &'a str) -> &'a [u8] {
-    unsafe {
-        let (ptr, len): (*u8, uint) = ::cast::transmute(s);
-        let outgoing_tuple: (*u8, uint) = (ptr, len - 1);
-        return ::cast::transmute(outgoing_tuple);
-    }
-}
-
 /**
  * A dummy trait to hold all the utility methods that we implement on strings.
  */
@@ -1237,7 +938,7 @@ fn as_c_str<T>(self, f: &fn(*libc::c_char) -> T) -> T {
             // NB: len includes the trailing null.
             assert!(len > 0);
             if unsafe { *(ptr::offset(buf,len-1)) != 0 } {
-                to_owned(self).as_c_str(f)
+                self.to_owned().as_c_str(f)
             } else {
                 f(buf as *libc::c_char)
             }
@@ -1304,39 +1005,6 @@ pub fn subslice_offset(outer: &str, inner: &str) -> uint {
     }
 }
 
-
-/**
- * Returns the number of single-byte characters the string can hold without
- * reallocating
- */
-pub fn capacity(s: &const ~str) -> uint {
-    do as_bytes(s) |buf| {
-        let vcap = vec::capacity(buf);
-        assert!(vcap > 0u);
-        vcap - 1u
-    }
-}
-
-/// Escape each char in `s` with char::escape_default.
-pub fn escape_default(s: &str) -> ~str {
-    let mut out: ~str = ~"";
-    out.reserve_at_least(s.len());
-    for s.iter().advance |c| {
-        out.push_str(char::escape_default(c));
-    }
-    out
-}
-
-/// Escape each char in `s` with char::escape_unicode.
-pub fn escape_unicode(s: &str) -> ~str {
-    let mut out: ~str = ~"";
-    out.reserve_at_least(s.len());
-    for s.iter().advance |c| {
-        out.push_str(char::escape_unicode(c));
-    }
-    out
-}
-
 /// Unsafe operations
 pub mod raw {
     use cast;
@@ -1521,12 +1189,12 @@ fn test_from_buf_len() {
 #[cfg(not(test))]
 pub mod traits {
     use ops::Add;
-    use str::append;
-
     impl<'self> Add<&'self str,~str> for ~str {
         #[inline(always)]
         fn add(&self, rhs: & &'self str) -> ~str {
-            append(copy *self, (*rhs))
+            let mut s = self.to_owned();
+            s.push_str(*rhs);
+            s
         }
     }
 }
@@ -1534,6 +1202,29 @@ fn add(&self, rhs: & &'self str) -> ~str {
 #[cfg(test)]
 pub mod traits {}
 
+/// Any string that can be represented as a slice
+pub trait Str {
+    /// Work with `self` as a slice.
+    fn as_slice<'a>(&'a self) -> &'a str;
+}
+
+impl<'self> Str for &'self str {
+    #[inline(always)]
+    fn as_slice<'a>(&'a self) -> &'a str { *self }
+}
+impl<'self> Str for ~str {
+    #[inline(always)]
+    fn as_slice<'a>(&'a self) -> &'a str {
+        let s: &'a str = *self; s
+    }
+}
+impl<'self> Str for @str {
+    #[inline(always)]
+    fn as_slice<'a>(&'a self) -> &'a str {
+        let s: &'a str = *self; s
+    }
+}
+
 #[allow(missing_doc)]
 pub trait StrSlice<'self> {
     fn contains<'a>(&self, needle: &'a str) -> bool;
@@ -1556,19 +1247,23 @@ fn split_options_iter<Sep: CharEq>(&self, sep: Sep, count: uint, allow_trailing_
     fn is_alphanumeric(&self) -> bool;
     fn len(&self) -> uint;
     fn char_len(&self) -> uint;
+
     fn slice(&self, begin: uint, end: uint) -> &'self str;
     fn slice_from(&self, begin: uint) -> &'self str;
     fn slice_to(&self, end: uint) -> &'self str;
+
+    fn slice_chars(&self, begin: uint, end: uint) -> &'self str;
+
     fn starts_with(&self, needle: &str) -> bool;
-    fn substr(&self, begin: uint, n: uint) -> &'self str;
     fn escape_default(&self) -> ~str;
     fn escape_unicode(&self) -> ~str;
     fn trim(&self) -> &'self str;
     fn trim_left(&self) -> &'self str;
     fn trim_right(&self) -> &'self str;
-    fn trim_chars(&self, chars_to_trim: &[char]) -> &'self str;
-    fn trim_left_chars(&self, chars_to_trim: &[char]) -> &'self str;
-    fn trim_right_chars(&self, chars_to_trim: &[char]) -> &'self str;
+    fn trim_chars<C: CharEq>(&self, to_trim: &C) -> &'self str;
+    fn trim_left_chars<C: CharEq>(&self, to_trim: &C) -> &'self str;
+    fn trim_right_chars<C: CharEq>(&self, to_trim: &C) -> &'self str;
+    fn replace(&self, from: &str, to: &str) -> ~str;
     fn to_owned(&self) -> ~str;
     fn to_managed(&self) -> @str;
     fn is_char_boundary(&self, index: uint) -> bool;
@@ -1576,11 +1271,15 @@ fn split_options_iter<Sep: CharEq>(&self, sep: Sep, count: uint, allow_trailing_
     fn char_at(&self, i: uint) -> char;
     fn char_range_at_reverse(&self, start: uint) -> CharRange;
     fn char_at_reverse(&self, i: uint) -> char;
-    fn to_bytes(&self) -> ~[u8];
+    fn as_bytes(&self) -> &'self [u8];
 
     fn find<C: CharEq>(&self, search: C) -> Option<uint>;
     fn rfind<C: CharEq>(&self, search: C) -> Option<uint>;
     fn find_str(&self, &str) -> Option<uint>;
+
+    fn repeat(&self, nn: uint) -> ~str;
+
+    fn slice_shift_char(&self) -> (char, &'self str);
 }
 
 /// Extension methods for strings
@@ -1635,12 +1334,12 @@ fn rev_iter(&self) -> StrCharRevIterator<'self> {
     /// An iterator over the bytes of `self`
     #[inline]
     fn bytes_iter(&self) -> StrBytesIterator<'self> {
-        StrBytesIterator { it: as_bytes_slice(*self).iter() }
+        StrBytesIterator { it: self.as_bytes().iter() }
     }
     /// An iterator over the bytes of `self`, in reverse order
     #[inline]
     fn bytes_rev_iter(&self) -> StrBytesRevIterator<'self> {
-        StrBytesRevIterator { it: as_bytes_slice(*self).rev_iter() }
+        StrBytesRevIterator { it: self.as_bytes().rev_iter() }
     }
 
     /// An iterator over substrings of `self`, separated by characters
@@ -1753,7 +1452,8 @@ fn len(&self) -> uint {
     }
     /// Returns the number of characters that a string holds
     #[inline]
-    fn char_len(&self) -> uint { char_len(*self) }
+    fn char_len(&self) -> uint { self.iter().count() }
+
     /**
      * Returns a slice of the given string from the byte range
      * [`begin`..`end`)
@@ -1784,6 +1484,32 @@ fn slice_from(&self, begin: uint) -> &'self str {
     fn slice_to(&self, end: uint) -> &'self str {
         self.slice(0, end)
     }
+
+    /// Returns a slice of the string from the char range
+    /// [`begin`..`end`).
+    ///
+    /// Fails if `begin` > `end` or the either `begin` or `end` are
+    /// beyond the last character of the string.
+    fn slice_chars(&self, begin: uint, end: uint) -> &'self str {
+        assert!(begin <= end);
+        // not sure how to use the iterators for this nicely.
+        let mut (position, count) = (0, 0);
+        let l = self.len();
+        while count < begin && position < l {
+            position = self.char_range_at(position).next;
+            count += 1;
+        }
+        if count < begin { fail!("Attempted to begin slice_chars beyond end of string") }
+        let start_byte = position;
+        while count < end && position < l {
+            position = self.char_range_at(position).next;
+            count += 1;
+        }
+        if count < end { fail!("Attempted to end slice_chars beyond end of string") }
+
+        self.slice(start_byte, position)
+    }
+
     /// Returns true if `needle` is a prefix of the string.
     fn starts_with<'a>(&self, needle: &'a str) -> bool {
         let (self_len, needle_len) = (self.len(), needle.len());
@@ -1792,29 +1518,32 @@ fn starts_with<'a>(&self, needle: &'a str) -> bool {
         else { match_at(*self, needle, 0u) }
     }
     /// Returns true if `needle` is a suffix of the string.
-    pub fn ends_with(&self, needle: &str) -> bool {
+    fn ends_with(&self, needle: &str) -> bool {
         let (self_len, needle_len) = (self.len(), needle.len());
         if needle_len == 0u { true }
         else if needle_len > self_len { false }
         else { match_at(*self, needle, self_len - needle_len) }
     }
 
-    /**
-     * Take a substring of another.
-     *
-     * Returns a string containing `n` characters starting at byte offset
-     * `begin`.
-     */
-    #[inline]
-    fn substr(&self, begin: uint, n: uint) -> &'self str {
-        self.slice(begin, begin + count_bytes(*self, begin, n))
-    }
     /// Escape each char in `s` with char::escape_default.
-    #[inline]
-    fn escape_default(&self) -> ~str { escape_default(*self) }
+    fn escape_default(&self) -> ~str {
+        let mut out: ~str = ~"";
+        out.reserve_at_least(self.len());
+        for self.iter().advance |c| {
+            out.push_str(char::escape_default(c));
+        }
+        out
+    }
+
     /// Escape each char in `s` with char::escape_unicode.
-    #[inline]
-    fn escape_unicode(&self) -> ~str { escape_unicode(*self) }
+    fn escape_unicode(&self) -> ~str {
+        let mut out: ~str = ~"";
+        out.reserve_at_least(self.len());
+        for self.iter().advance |c| {
+            out.push_str(char::escape_unicode(c));
+        }
+        out
+    }
 
     /// Returns a string with leading and trailing whitespace removed
     #[inline]
@@ -1824,49 +1553,51 @@ fn trim(&self) -> &'self str {
     /// Returns a string with leading whitespace removed
     #[inline]
     fn trim_left(&self) -> &'self str {
-        match self.find(|c| !char::is_whitespace(c)) {
-            None => "",
-            Some(first) => unsafe { raw::slice_bytes(*self, first, self.len()) }
-        }
+        self.trim_left_chars(&char::is_whitespace)
     }
     /// Returns a string with trailing whitespace removed
     #[inline]
     fn trim_right(&self) -> &'self str {
-        match self.rfind(|c| !char::is_whitespace(c)) {
-            None => "",
-            Some(last) => {
-                let next = self.char_range_at(last).next;
-                unsafe { raw::slice_bytes(*self, 0u, next) }
-            }
-        }
+        self.trim_right_chars(&char::is_whitespace)
     }
 
     /**
-     * Returns a string with leading and trailing `chars_to_trim` removed.
+     * Returns a string with characters that match `to_trim` removed.
      *
      * # Arguments
      *
-     * * chars_to_trim - A vector of chars
+     * * to_trim - a character matcher
      *
+     * # Example
+     *
+     * ~~~
+     * assert_eq!("11foo1bar11".trim_chars(&'1'), "foo1bar")
+     * assert_eq!("12foo1bar12".trim_chars(& &['1', '2']), "foo1bar")
+     * assert_eq!("123foo1bar123".trim_chars(&|c: char| c.is_digit()), "foo1bar")
+     * ~~~
      */
     #[inline]
-    fn trim_chars(&self, chars_to_trim: &[char]) -> &'self str {
-        self.trim_left_chars(chars_to_trim).trim_right_chars(chars_to_trim)
+    fn trim_chars<C: CharEq>(&self, to_trim: &C) -> &'self str {
+        self.trim_left_chars(to_trim).trim_right_chars(to_trim)
     }
     /**
      * Returns a string with leading `chars_to_trim` removed.
      *
      * # Arguments
      *
-     * * s - A string
-     * * chars_to_trim - A vector of chars
+     * * to_trim - a character matcher
      *
+     * # Example
+     *
+     * ~~~
+     * assert_eq!("11foo1bar11".trim_left_chars(&'1'), "foo1bar11")
+     * assert_eq!("12foo1bar12".trim_left_chars(& &['1', '2']), "foo1bar12")
+     * assert_eq!("123foo1bar123".trim_left_chars(&|c: char| c.is_digit()), "foo1bar123")
+     * ~~~
      */
     #[inline]
-    fn trim_left_chars(&self, chars_to_trim: &[char]) -> &'self str {
-        if chars_to_trim.is_empty() { return *self; }
-
-        match self.find(|c| !chars_to_trim.contains(&c)) {
+    fn trim_left_chars<C: CharEq>(&self, to_trim: &C) -> &'self str {
+        match self.find(|c: char| !to_trim.matches(c)) {
             None => "",
             Some(first) => unsafe { raw::slice_bytes(*self, first, self.len()) }
         }
@@ -1876,15 +1607,19 @@ fn trim_left_chars(&self, chars_to_trim: &[char]) -> &'self str {
      *
      * # Arguments
      *
-     * * s - A string
-     * * chars_to_trim - A vector of chars
+     * * to_trim - a character matcher
      *
+     * # Example
+     *
+     * ~~~
+     * assert_eq!("11foo1bar11".trim_right_chars(&'1'), "11foo1bar")
+     * assert_eq!("12foo1bar12".trim_right_chars(& &['1', '2']), "12foo1bar")
+     * assert_eq!("123foo1bar123".trim_right_chars(&|c: char| c.is_digit()), "123foo1bar")
+     * ~~~
      */
     #[inline]
-    fn trim_right_chars(&self, chars_to_trim: &[char]) -> &'self str {
-        if chars_to_trim.is_empty() { return *self; }
-
-        match self.rfind(|c| !chars_to_trim.contains(&c)) {
+    fn trim_right_chars<C: CharEq>(&self, to_trim: &C) -> &'self str {
+        match self.rfind(|c: char| !to_trim.matches(c)) {
             None => "",
             Some(last) => {
                 let next = self.char_range_at(last).next;
@@ -1893,10 +1628,36 @@ fn trim_right_chars(&self, chars_to_trim: &[char]) -> &'self str {
         }
     }
 
+    /**
+     * Replace all occurrences of one string with another
+     *
+     * # Arguments
+     *
+     * * from - The string to replace
+     * * to - The replacement string
+     *
+     * # Return value
+     *
+     * The original string with all occurances of `from` replaced with `to`
+     */
+    pub fn replace(&self, from: &str, to: &str) -> ~str {
+        let mut (result, last_end) = (~"", 0);
+        for self.matches_index_iter(from).advance |(start, end)| {
+            result.push_str(unsafe{raw::slice_bytes(*self, last_end, start)});
+            result.push_str(to);
+            last_end = end;
+        }
+        result.push_str(unsafe{raw::slice_bytes(*self, last_end, self.len())});
+        result
+    }
 
+    /// Copy a slice into a new unique str
     #[inline]
-    fn to_owned(&self) -> ~str { to_owned(*self) }
+    fn to_owned(&self) -> ~str {
+        unsafe { raw::slice_bytes_owned(*self, 0, self.len()) }
+    }
 
+    /// Copy a slice into a new @str
     #[inline]
     fn to_managed(&self) -> @str {
         let v = at_vec::from_fn(self.len() + 1, |i| {
@@ -2023,7 +1784,18 @@ fn char_at_reverse(&self, i: uint) -> char {
         self.char_range_at_reverse(i).ch
     }
 
-    fn to_bytes(&self) -> ~[u8] { to_bytes(*self) }
+    /**
+     * Work with the byte buffer of a string as a byte slice.
+     *
+     * The byte slice does not include the null terminator.
+     */
+    fn as_bytes(&self) -> &'self [u8] {
+        unsafe {
+            let (ptr, len): (*u8, uint) = ::cast::transmute(*self);
+            let outgoing_tuple: (*u8, uint) = (ptr, len - 1);
+            ::cast::transmute(outgoing_tuple)
+        }
+    }
 
     /**
      * Returns the byte index of the first character of `self` that matches `search`
@@ -2094,6 +1866,92 @@ fn find_str(&self, needle: &str) -> Option<uint> {
                 .map_consume(|(start, _end)| start)
         }
     }
+
+    /// Given a string, make a new string with repeated copies of it.
+    fn repeat(&self, nn: uint) -> ~str {
+        do as_buf(*self) |buf, len| {
+            let mut ret = ~"";
+            // ignore the NULL terminator
+            let len = len - 1;
+            ret.reserve(nn * len);
+
+            unsafe {
+                do as_buf(ret) |rbuf, _len| {
+                    let mut rbuf = ::cast::transmute_mut_unsafe(rbuf);
+
+                    for nn.times {
+                        ptr::copy_memory(rbuf, buf, len);
+                        rbuf = rbuf.offset(len);
+                    }
+                }
+                raw::set_len(&mut ret, nn * len);
+            }
+            ret
+        }
+    }
+
+    /**
+     * Retrieves the first character from a string slice and returns
+     * it. This does not allocate a new string; instead, it returns a
+     * slice that point one character beyond the character that was
+     * shifted.
+     *
+     * # Failure
+     *
+     * If the string does not contain any characters
+     */
+    #[inline]
+    fn slice_shift_char(&self) -> (char, &'self str) {
+        let CharRange {ch, next} = self.char_range_at(0u);
+        let next_s = unsafe { raw::slice_bytes(*self, next, self.len()) };
+        return (ch, next_s);
+    }
+
+
+}
+
+#[allow(missing_doc)]
+pub trait NullTerminatedStr {
+    fn as_bytes_with_null<'a>(&'a self) -> &'a [u8];
+}
+
+impl NullTerminatedStr for ~str {
+    /**
+     * Work with the byte buffer of a string as a byte slice.
+     *
+     * The byte slice does include the null terminator.
+     */
+    #[inline]
+    fn as_bytes_with_null<'a>(&'a self) -> &'a [u8] {
+        let ptr: &'a ~[u8] = unsafe { ::cast::transmute(self) };
+        let slice: &'a [u8] = *ptr;
+        slice
+    }
+}
+impl NullTerminatedStr for @str {
+    /**
+     * Work with the byte buffer of a string as a byte slice.
+     *
+     * The byte slice does include the null terminator.
+     */
+    #[inline]
+    fn as_bytes_with_null<'a>(&'a self) -> &'a [u8] {
+        let ptr: &'a ~[u8] = unsafe { ::cast::transmute(self) };
+        let slice: &'a [u8] = *ptr;
+        slice
+    }
+}
+// static strings are the only slices guaranteed to a nul-terminator
+impl NullTerminatedStr for &'static str {
+    /**
+     * Work with the byte buffer of a string as a byte slice.
+     *
+     * The byte slice does include the null terminator.
+     */
+    #[inline]
+    fn as_bytes_with_null(&self) -> &'static [u8] {
+        unsafe { ::cast::transmute(*self) }
+    }
 }
 
 #[allow(missing_doc)]
@@ -2101,8 +1959,15 @@ pub trait OwnedStr {
     fn push_str_no_overallocate(&mut self, rhs: &str);
     fn push_str(&mut self, rhs: &str);
     fn push_char(&mut self, c: char);
+    fn pop_char(&mut self) -> char;
+    fn shift_char(&mut self) -> char;
+    fn unshift_char(&mut self, ch: char);
+    fn append(&self, rhs: &str) -> ~str; // FIXME #4850: this should consume self.
     fn reserve(&mut self, n: uint);
     fn reserve_at_least(&mut self, n: uint);
+    fn capacity(&self) -> uint;
+
+    fn as_bytes_with_null_consume(self) -> ~[u8];
 }
 
 impl OwnedStr for ~str {
@@ -2198,6 +2063,51 @@ fn push_char(&mut self, c: char) {
             raw::set_len(self, new_len);
         }
     }
+    /**
+     * Remove the final character from a string and return it
+     *
+     * # Failure
+     *
+     * If the string does not contain any characters
+     */
+    fn pop_char(&mut self) -> char {
+        let end = self.len();
+        assert!(end > 0u);
+        let CharRange {ch, next} = self.char_range_at_reverse(end);
+        unsafe { raw::set_len(self, next); }
+        return ch;
+    }
+
+    /**
+     * Remove the first character from a string and return it
+     *
+     * # Failure
+     *
+     * If the string does not contain any characters
+     */
+    fn shift_char(&mut self) -> char {
+        let CharRange {ch, next} = self.char_range_at(0u);
+        *self = unsafe { raw::slice_bytes_owned(*self, next, self.len()) };
+        return ch;
+    }
+
+    /// Prepend a char to a string
+    fn unshift_char(&mut self, ch: char) {
+        // This could be more efficient.
+        let mut new_str = ~"";
+        new_str.push_char(ch);
+        new_str.push_str(*self);
+        *self = new_str;
+    }
+
+    /// Concatenate two strings together.
+    #[inline]
+    fn append(&self, rhs: &str) -> ~str {
+        // FIXME #4850: this should consume self, but that causes segfaults
+        let mut v = self.clone();
+        v.push_str_no_overallocate(rhs);
+        v
+    }
 
     /**
      * Reserves capacity for exactly `n` bytes in the given string, not including
@@ -2247,12 +2157,30 @@ pub fn reserve(&mut self, n: uint) {
     fn reserve_at_least(&mut self, n: uint) {
         self.reserve(uint::next_power_of_two(n + 1u) - 1u)
     }
+
+    /**
+     * Returns the number of single-byte characters the string can hold without
+     * reallocating
+     */
+    fn capacity(&self) -> uint {
+        let buf: &const ~[u8] = unsafe { cast::transmute(self) };
+        let vcap = vec::capacity(buf);
+        assert!(vcap > 0u);
+        vcap - 1u
+    }
+
+    /// Convert to a vector of bytes. This does not allocate a new
+    /// string, and includes the null terminator.
+    #[inline]
+    fn as_bytes_with_null_consume(self) -> ~[u8] {
+        unsafe { ::cast::transmute(self) }
+    }
 }
 
 impl Clone for ~str {
     #[inline(always)]
     fn clone(&self) -> ~str {
-        to_owned(*self)
+        self.to_owned()
     }
 }
 
@@ -2332,7 +2260,7 @@ mod tests {
     use ptr;
     use str::*;
     use vec;
-    use vec::ImmutableVector;
+    use vec::{ImmutableVector, CopyableVector};
     use cmp::{TotalOrd, Less, Equal, Greater};
 
     #[test]
@@ -2367,14 +2295,14 @@ fn test_len() {
         assert_eq!("\u2620".len(), 3u);
         assert_eq!("\U0001d11e".len(), 4u);
 
-        assert_eq!(char_len(""), 0u);
-        assert_eq!(char_len("hello world"), 11u);
-        assert_eq!(char_len("\x63"), 1u);
-        assert_eq!(char_len("\xa2"), 1u);
-        assert_eq!(char_len("\u03c0"), 1u);
-        assert_eq!(char_len("\u2620"), 1u);
-        assert_eq!(char_len("\U0001d11e"), 1u);
-        assert_eq!(char_len("ประเทศไทย中华Việt Nam"), 19u);
+        assert_eq!("".char_len(), 0u);
+        assert_eq!("hello world".char_len(), 11u);
+        assert_eq!("\x63".char_len(), 1u);
+        assert_eq!("\xa2".char_len(), 1u);
+        assert_eq!("\u03c0".char_len(), 1u);
+        assert_eq!("\u2620".char_len(), 1u);
+        assert_eq!("\U0001d11e".char_len(), 1u);
+        assert_eq!("ประเทศไทย中华Việt Nam".char_len(), 19u);
     }
 
     #[test]
@@ -2397,10 +2325,31 @@ fn test_rfind() {
         assert_eq!("ประเทศไทย中华Việt Nam".rfind(|c: char| c == '华'), Some(30u));
     }
 
+    #[test]
+    fn test_push_str() {
+        let mut s = ~"";
+        s.push_str("");
+        assert_eq!(s.slice_from(0), "");
+        s.push_str("abc");
+        assert_eq!(s.slice_from(0), "abc");
+        s.push_str("ประเทศไทย中华Việt Nam");
+        assert_eq!(s.slice_from(0), "abcประเทศไทย中华Việt Nam");
+    }
+    #[test]
+    fn test_append() {
+        let mut s = ~"";
+        s = s.append("");
+        assert_eq!(s.slice_from(0), "");
+        s = s.append("abc");
+        assert_eq!(s.slice_from(0), "abc");
+        s = s.append("ประเทศไทย中华Việt Nam");
+        assert_eq!(s.slice_from(0), "abcประเทศไทย中华Việt Nam");
+    }
+
     #[test]
     fn test_pop_char() {
         let mut data = ~"ประเทศไทย中华";
-        let cc = pop_char(&mut data);
+        let cc = data.pop_char();
         assert_eq!(~"ประเทศไทย中", data);
         assert_eq!('华', cc);
     }
@@ -2408,7 +2357,7 @@ fn test_pop_char() {
     #[test]
     fn test_pop_char_2() {
         let mut data2 = ~"华";
-        let cc2 = pop_char(&mut data2);
+        let cc2 = data2.pop_char();
         assert_eq!(~"", data2);
         assert_eq!('华', cc2);
     }
@@ -2418,7 +2367,29 @@ fn test_pop_char_2() {
     #[ignore(cfg(windows))]
     fn test_pop_char_fail() {
         let mut data = ~"";
-        let _cc3 = pop_char(&mut data);
+        let _cc3 = data.pop_char();
+    }
+
+    #[test]
+    fn test_push_char() {
+        let mut data = ~"ประเทศไทย中";
+        data.push_char('华');
+        assert_eq!(~"ประเทศไทย中华", data);
+    }
+
+    #[test]
+    fn test_shift_char() {
+        let mut data = ~"ประเทศไทย中";
+        let cc = data.shift_char();
+        assert_eq!(~"ระเทศไทย中", data);
+        assert_eq!('ป', cc);
+    }
+
+    #[test]
+    fn test_unshift_char() {
+        let mut data = ~"ประเทศไทย中";
+        data.unshift_char('华');
+        assert_eq!(~"华ประเทศไทย中", data);
     }
 
     #[test]
@@ -2466,13 +2437,13 @@ fn test_find_str() {
     }
 
     #[test]
-    fn test_substr() {
-        fn t(a: &str, b: &str, start: int) {
-            assert_eq!(a.substr(start as uint, b.len()), b);
+    fn test_slice_chars() {
+        fn t(a: &str, b: &str, start: uint) {
+            assert_eq!(a.slice_chars(start, start + b.char_len()), b);
         }
         t("hello", "llo", 2);
         t("hello", "el", 1);
-        assert_eq!("ะเทศไท", "ประเทศไทย中华Việt Nam".substr(6u, 6u));
+        assert_eq!("ะเทศไท", "ประเทศไทย中华Việt Nam".slice_chars(2, 8));
     }
 
     #[test]
@@ -2522,11 +2493,11 @@ fn t(v: &[&str], sep: &str, s: &str) {
 
     #[test]
     fn test_repeat() {
-        assert_eq!(repeat("x", 4), ~"xxxx");
-        assert_eq!(repeat("hi", 4), ~"hihihihi");
-        assert_eq!(repeat("ไท华", 3), ~"ไท华ไท华ไท华");
-        assert_eq!(repeat("", 4), ~"");
-        assert_eq!(repeat("hi", 0), ~"");
+        assert_eq!("x".repeat(4), ~"xxxx");
+        assert_eq!("hi".repeat(4), ~"hihihihi");
+        assert_eq!("ไท华".repeat(3), ~"ไท华ไท华ไท华");
+        assert_eq!("".repeat(4), ~"");
+        assert_eq!("hi".repeat(0), ~"");
     }
 
     #[test]
@@ -2578,13 +2549,13 @@ fn test_is_empty() {
     #[test]
     fn test_replace() {
         let a = "a";
-        assert_eq!(replace("", a, "b"), ~"");
-        assert_eq!(replace("a", a, "b"), ~"b");
-        assert_eq!(replace("ab", a, "b"), ~"bb");
+        assert_eq!("".replace(a, "b"), ~"");
+        assert_eq!("a".replace(a, "b"), ~"b");
+        assert_eq!("ab".replace(a, "b"), ~"bb");
         let test = "test";
-        assert!(replace(" test test ", test, "toast") ==
+        assert!(" test test ".replace(test, "toast") ==
             ~" toast toast ");
-        assert_eq!(replace(" test test ", test, ""), ~"   ");
+        assert_eq!(" test test ".replace(test, ""), ~"   ");
     }
 
     #[test]
@@ -2594,7 +2565,7 @@ fn test_replace_2a() {
 
         let a = ~"ประเ";
         let A = ~"دولة الكويتทศไทย中华";
-        assert_eq!(replace(data, a, repl), A);
+        assert_eq!(data.replace(a, repl), A);
     }
 
     #[test]
@@ -2604,7 +2575,7 @@ fn test_replace_2b() {
 
         let b = ~"ะเ";
         let B = ~"ปรدولة الكويتทศไทย中华";
-        assert_eq!(replace(data, b,   repl), B);
+        assert_eq!(data.replace(b,   repl), B);
     }
 
     #[test]
@@ -2614,7 +2585,7 @@ fn test_replace_2c() {
 
         let c = ~"中华";
         let C = ~"ประเทศไทยدولة الكويت";
-        assert_eq!(replace(data, c, repl), C);
+        assert_eq!(data.replace(c, repl), C);
     }
 
     #[test]
@@ -2623,7 +2594,7 @@ fn test_replace_2d() {
         let repl = ~"دولة الكويت";
 
         let d = ~"ไท华";
-        assert_eq!(replace(data, d, repl), data);
+        assert_eq!(data.replace(d, repl), data);
     }
 
     #[test]
@@ -2707,26 +2678,41 @@ fn test_slice_to() {
 
     #[test]
     fn test_trim_left_chars() {
-        assert_eq!(" *** foo *** ".trim_left_chars([]), " *** foo *** ");
-        assert_eq!(" *** foo *** ".trim_left_chars(['*', ' ']), "foo *** ");
-        assert_eq!(" ***  *** ".trim_left_chars(['*', ' ']), "");
-        assert_eq!("foo *** ".trim_left_chars(['*', ' ']), "foo *** ");
+        let v: &[char] = &[];
+        assert_eq!(" *** foo *** ".trim_left_chars(&v), " *** foo *** ");
+        assert_eq!(" *** foo *** ".trim_left_chars(& &['*', ' ']), "foo *** ");
+        assert_eq!(" ***  *** ".trim_left_chars(& &['*', ' ']), "");
+        assert_eq!("foo *** ".trim_left_chars(& &['*', ' ']), "foo *** ");
+
+        assert_eq!("11foo1bar11".trim_left_chars(&'1'), "foo1bar11");
+        assert_eq!("12foo1bar12".trim_left_chars(& &['1', '2']), "foo1bar12");
+        assert_eq!("123foo1bar123".trim_left_chars(&|c: char| c.is_digit()), "foo1bar123");
     }
 
     #[test]
     fn test_trim_right_chars() {
-        assert_eq!(" *** foo *** ".trim_right_chars([]), " *** foo *** ");
-        assert_eq!(" *** foo *** ".trim_right_chars(['*', ' ']), " *** foo");
-        assert_eq!(" ***  *** ".trim_right_chars(['*', ' ']), "");
-        assert_eq!(" *** foo".trim_right_chars(['*', ' ']), " *** foo");
+        let v: &[char] = &[];
+        assert_eq!(" *** foo *** ".trim_right_chars(&v), " *** foo *** ");
+        assert_eq!(" *** foo *** ".trim_right_chars(& &['*', ' ']), " *** foo");
+        assert_eq!(" ***  *** ".trim_right_chars(& &['*', ' ']), "");
+        assert_eq!(" *** foo".trim_right_chars(& &['*', ' ']), " *** foo");
+
+        assert_eq!("11foo1bar11".trim_right_chars(&'1'), "11foo1bar");
+        assert_eq!("12foo1bar12".trim_right_chars(& &['1', '2']), "12foo1bar");
+        assert_eq!("123foo1bar123".trim_right_chars(&|c: char| c.is_digit()), "123foo1bar");
     }
 
     #[test]
     fn test_trim_chars() {
-        assert_eq!(" *** foo *** ".trim_chars([]), " *** foo *** ");
-        assert_eq!(" *** foo *** ".trim_chars(['*', ' ']), "foo");
-        assert_eq!(" ***  *** ".trim_chars(['*', ' ']), "");
-        assert_eq!("foo".trim_chars(['*', ' ']), "foo");
+        let v: &[char] = &[];
+        assert_eq!(" *** foo *** ".trim_chars(&v), " *** foo *** ");
+        assert_eq!(" *** foo *** ".trim_chars(& &['*', ' ']), "foo");
+        assert_eq!(" ***  *** ".trim_chars(& &['*', ' ']), "");
+        assert_eq!("foo".trim_chars(& &['*', ' ']), "foo");
+
+        assert_eq!("11foo1bar11".trim_chars(&'1'), "foo1bar");
+        assert_eq!("12foo1bar12".trim_chars(& &['1', '2']), "foo1bar");
+        assert_eq!("123foo1bar123".trim_chars(&|c: char| c.is_digit()), "foo1bar");
     }
 
     #[test]
@@ -2905,12 +2891,70 @@ fn test_from_buf() {
         }
     }
 
+    #[test]
+    fn test_as_bytes() {
+        // no null
+        let v = [
+            224, 184, 168, 224, 185, 132, 224, 184, 151, 224, 184, 162, 228,
+            184, 173, 229, 141, 142, 86, 105, 225, 187, 135, 116, 32, 78, 97,
+            109
+        ];
+        assert_eq!("".as_bytes(), &[]);
+        assert_eq!("abc".as_bytes(), &['a' as u8, 'b' as u8, 'c' as u8]);
+        assert_eq!("ศไทย中华Việt Nam".as_bytes(), v);
+    }
+
+    #[test]
+    fn test_as_bytes_with_null() {
+        // has null
+        let v = [
+            224, 184, 168, 224, 185, 132, 224, 184, 151, 224, 184, 162, 228,
+            184, 173, 229, 141, 142, 86, 105, 225, 187, 135, 116, 32, 78, 97,
+            109, 0
+        ];
+
+        assert_eq!("".as_bytes_with_null(), &[0]);
+        assert_eq!("abc".as_bytes_with_null(), &['a' as u8, 'b' as u8, 'c' as u8, 0]);
+        assert_eq!("ศไทย中华Việt Nam".as_bytes_with_null(), v);
+
+        let s1 = @"";
+        let s2 = @"abc";
+        let s3 = @"ศไทย中华Việt Nam";
+        assert_eq!(s1.as_bytes_with_null(), &[0]);
+        assert_eq!(s2.as_bytes_with_null(), &['a' as u8, 'b' as u8, 'c' as u8, 0]);
+        assert_eq!(s3.as_bytes_with_null(), v);
+
+        let s1 = ~"";
+        let s2 = ~"abc";
+        let s3 = ~"ศไทย中华Việt Nam";
+        assert_eq!(s1.as_bytes_with_null(), &[0]);
+        assert_eq!(s2.as_bytes_with_null(), &['a' as u8, 'b' as u8, 'c' as u8, 0]);
+        assert_eq!(s3.as_bytes_with_null(), v);
+    }
+
+    #[test]
+    fn test_as_bytes_with_null_consume() {
+        let s = ~"ศไทย中华Việt Nam";
+        let v = ~[
+            224, 184, 168, 224, 185, 132, 224, 184, 151, 224, 184, 162, 228,
+            184, 173, 229, 141, 142, 86, 105, 225, 187, 135, 116, 32, 78, 97,
+            109, 0
+        ];
+        assert_eq!((~"").as_bytes_with_null_consume(), ~[0]);
+        assert_eq!((~"abc").as_bytes_with_null_consume(),
+                   ~['a' as u8, 'b' as u8, 'c' as u8, 0]);
+        assert_eq!(s.as_bytes_with_null_consume(), v);
+    }
+
     #[test]
     #[ignore(cfg(windows))]
     #[should_fail]
     fn test_as_bytes_fail() {
-        // Don't double free
-        as_bytes::<()>(&~"", |_bytes| fail!() );
+        // Don't double free. (I'm not sure if this exercises the
+        // original problem code path anymore.)
+        let s = ~"";
+        let _bytes = s.as_bytes_with_null();
+        fail!();
     }
 
     #[test]
@@ -2985,7 +3029,7 @@ fn test_subslice_offset_2() {
     fn vec_str_conversions() {
         let s1: ~str = ~"All mimsy were the borogoves";
 
-        let v: ~[u8] = to_bytes(s1);
+        let v: ~[u8] = s1.as_bytes().to_owned();
         let s2: ~str = from_bytes(v);
         let mut i: uint = 0u;
         let n1: uint = s1.len();
@@ -3104,30 +3148,27 @@ fn test_char_at_reverse() {
 
     #[test]
     fn test_escape_unicode() {
-        assert_eq!(escape_unicode("abc"), ~"\\x61\\x62\\x63");
-        assert_eq!(escape_unicode("a c"), ~"\\x61\\x20\\x63");
-        assert_eq!(escape_unicode("\r\n\t"), ~"\\x0d\\x0a\\x09");
-        assert_eq!(escape_unicode("'\"\\"), ~"\\x27\\x22\\x5c");
-        assert!(escape_unicode("\x00\x01\xfe\xff") ==
-                     ~"\\x00\\x01\\xfe\\xff");
-        assert_eq!(escape_unicode("\u0100\uffff"), ~"\\u0100\\uffff");
-        assert!(escape_unicode("\U00010000\U0010ffff") ==
-            ~"\\U00010000\\U0010ffff");
-        assert_eq!(escape_unicode("ab\ufb00"), ~"\\x61\\x62\\ufb00");
-        assert_eq!(escape_unicode("\U0001d4ea\r"), ~"\\U0001d4ea\\x0d");
+        assert_eq!("abc".escape_unicode(), ~"\\x61\\x62\\x63");
+        assert_eq!("a c".escape_unicode(), ~"\\x61\\x20\\x63");
+        assert_eq!("\r\n\t".escape_unicode(), ~"\\x0d\\x0a\\x09");
+        assert_eq!("'\"\\".escape_unicode(), ~"\\x27\\x22\\x5c");
+        assert_eq!("\x00\x01\xfe\xff".escape_unicode(), ~"\\x00\\x01\\xfe\\xff");
+        assert_eq!("\u0100\uffff".escape_unicode(), ~"\\u0100\\uffff");
+        assert_eq!("\U00010000\U0010ffff".escape_unicode(), ~"\\U00010000\\U0010ffff");
+        assert_eq!("ab\ufb00".escape_unicode(), ~"\\x61\\x62\\ufb00");
+        assert_eq!("\U0001d4ea\r".escape_unicode(), ~"\\U0001d4ea\\x0d");
     }
 
     #[test]
     fn test_escape_default() {
-        assert_eq!(escape_default("abc"), ~"abc");
-        assert_eq!(escape_default("a c"), ~"a c");
-        assert_eq!(escape_default("\r\n\t"), ~"\\r\\n\\t");
-        assert_eq!(escape_default("'\"\\"), ~"\\'\\\"\\\\");
-        assert_eq!(escape_default("\u0100\uffff"), ~"\\u0100\\uffff");
-        assert!(escape_default("\U00010000\U0010ffff") ==
-            ~"\\U00010000\\U0010ffff");
-        assert_eq!(escape_default("ab\ufb00"), ~"ab\\ufb00");
-        assert_eq!(escape_default("\U0001d4ea\r"), ~"\\U0001d4ea\\r");
+        assert_eq!("abc".escape_default(), ~"abc");
+        assert_eq!("a c".escape_default(), ~"a c");
+        assert_eq!("\r\n\t".escape_default(), ~"\\r\\n\\t");
+        assert_eq!("'\"\\".escape_default(), ~"\\'\\\"\\\\");
+        assert_eq!("\u0100\uffff".escape_default(), ~"\\u0100\\uffff");
+        assert_eq!("\U00010000\U0010ffff".escape_default(), ~"\\U00010000\\U0010ffff");
+        assert_eq!("ab\ufb00".escape_default(), ~"ab\\ufb00");
+        assert_eq!("\U0001d4ea\r".escape_default(), ~"\\U0001d4ea\\r");
     }
 
     #[test]
@@ -3135,6 +3176,11 @@ fn test_to_managed() {
         assert_eq!("abc".to_managed(), @"abc");
         assert_eq!("abcdef".slice(1, 5).to_managed(), @"bcde");
     }
+    #[test]
+    fn test_to_owned() {
+        assert_eq!("abc".to_owned(), ~"abc");
+        assert_eq!("abcdef".slice(1, 5).to_owned(), ~"bcde");
+    }
 
     #[test]
     fn test_total_ord() {

src/libstd/to_bytes.rs

@@ -18,7 +18,7 @@
 use io::Writer;
 use option::{None, Option, Some};
 use old_iter::BaseIter;
-use str;
+use str::StrSlice;
 
 pub type Cb<'self> = &'self fn(buf: &[u8]) -> bool;
 
@@ -239,27 +239,25 @@ fn iter_bytes(&self, lsb0: bool, f: Cb) -> bool {
 impl<'self> IterBytes for &'self str {
     #[inline(always)]
     fn iter_bytes(&self, _lsb0: bool, f: Cb) -> bool {
-        do str::byte_slice(*self) |bytes| {
-            f(bytes)
-        }
+        f(self.as_bytes())
     }
 }
 
 impl IterBytes for ~str {
     #[inline(always)]
     fn iter_bytes(&self, _lsb0: bool, f: Cb) -> bool {
-        do str::byte_slice(*self) |bytes| {
-            f(bytes)
-        }
+        // this should possibly include the null terminator, but that
+        // breaks .find_equiv on hashmaps.
+        f(self.as_bytes())
     }
 }
 
 impl IterBytes for @str {
     #[inline(always)]
     fn iter_bytes(&self, _lsb0: bool, f: Cb) -> bool {
-        do str::byte_slice(*self) |bytes| {
-            f(bytes)
-        }
+        // this should possibly include the null terminator, but that
+        // breaks .find_equiv on hashmaps.
+        f(self.as_bytes())
     }
 }
 

src/libstd/unstable/extfmt.rs

@@ -325,7 +325,7 @@ pub fn parse_type(s: &str, i: uint, lim: uint, err: ErrorFn) ->
             'o' => TyOctal,
             'f' => TyFloat,
             '?' => TyPoly,
-            _ => err(~"unknown type in conversion: " + s.substr(i, 1))
+            _ => err(fmt!("unknown type in conversion: %c", s.char_at(i)))
         };
 
         Parsed::new(t, i + 1)
@@ -546,7 +546,7 @@ pub fn conv_str(cv: Conv, s: &str, buf: &mut ~str) {
         // displayed
         let unpadded = match cv.precision {
           CountImplied => s,
-          CountIs(max) => if (max as uint) < str::char_len(s) {
+          CountIs(max) => if (max as uint) < s.char_len() {
             s.slice(0, max as uint)
           } else {
             s
@@ -584,7 +584,7 @@ pub fn uint_to_str_prec(num: uint, radix: uint, prec: uint) -> ~str {
                 ~""
             } else {
                 let s = uint::to_str_radix(num, radix);
-                let len = str::char_len(s);
+                let len = s.char_len();
                 if len < prec {
                     let diff = prec - len;
                     let pad = str::from_chars(vec::from_elem(diff, '0'));
@@ -614,7 +614,7 @@ pub fn pad(cv: Conv, s: &str, head: Option<char>, mode: PadMode,
             }
             CountIs(width) => { width as uint }
         };
-        let strlen = str::char_len(s) + headsize;
+        let strlen = s.char_len() + headsize;
         if uwidth <= strlen {
             for head.iter().advance |&c| {
                 buf.push_char(c);

src/libstd/vec.rs

@@ -171,11 +171,6 @@ pub fn from_elem<T:Copy>(n_elts: uint, t: T) -> ~[T] {
     }
 }
 
-/// Creates a new unique vector with the same contents as the slice
-pub fn to_owned<T:Copy>(t: &[T]) -> ~[T] {
-    from_fn(t.len(), |i| t[i])
-}
-
 /// Creates a new vector with a capacity of `capacity`
 pub fn with_capacity<T>(capacity: uint) -> ~[T] {
     let mut vec = ~[];
@@ -1787,7 +1782,7 @@ pub trait CopyableVector<T> {
 
 /// Extension methods for vectors
 impl<'self,T:Copy> CopyableVector<T> for &'self [T] {
-    /// Returns a copy of `v`.
+    /// Creates a new unique vector with the same contents as the slice
     #[inline]
     fn to_owned(&self) -> ~[T] {
         let mut result = ~[];
@@ -1796,7 +1791,6 @@ fn to_owned(&self) -> ~[T] {
             result.push(copy *e);
         }
         result
-
     }
 }
 
@@ -3361,19 +3355,19 @@ fn test_each_permutation() {
         let mut results: ~[~[int]];
 
         results = ~[];
-        for each_permutation([]) |v| { results.push(to_owned(v)); }
+        for each_permutation([]) |v| { results.push(v.to_owned()); }
         assert_eq!(results, ~[~[]]);
 
         results = ~[];
-        for each_permutation([7]) |v| { results.push(to_owned(v)); }
+        for each_permutation([7]) |v| { results.push(v.to_owned()); }
         assert_eq!(results, ~[~[7]]);
 
         results = ~[];
-        for each_permutation([1,1]) |v| { results.push(to_owned(v)); }
+        for each_permutation([1,1]) |v| { results.push(v.to_owned()); }
         assert_eq!(results, ~[~[1,1],~[1,1]]);
 
         results = ~[];
-        for each_permutation([5,2,0]) |v| { results.push(to_owned(v)); }
+        for each_permutation([5,2,0]) |v| { results.push(v.to_owned()); }
         assert!(results ==
             ~[~[5,2,0],~[5,0,2],~[2,5,0],~[2,0,5],~[0,5,2],~[0,2,5]]);
     }

src/libsyntax/attr.rs

@@ -259,7 +259,7 @@ pub fn last_meta_item_list_by_name(items: ~[@ast::meta_item], name: &str)
 
 pub fn sort_meta_items(items: &[@ast::meta_item]) -> ~[@ast::meta_item] {
     // This is sort of stupid here, converting to a vec of mutables and back
-    let mut v = vec::to_owned(items);
+    let mut v = items.to_owned();
     do extra::sort::quick_sort(v) |ma, mb| {
         get_meta_item_name(*ma) <= get_meta_item_name(*mb)
     }

src/libsyntax/ext/asm.rs

@@ -21,8 +21,6 @@
 use parse;
 use parse::token;
 
-use core::vec;
-
 enum State {
     Asm,
     Outputs,
@@ -45,7 +43,7 @@ pub fn expand_asm(cx: @ExtCtxt, sp: span, tts: &[ast::token_tree])
                -> base::MacResult {
     let p = parse::new_parser_from_tts(cx.parse_sess(),
                                        cx.cfg(),
-                                       vec::to_owned(tts));
+                                       tts.to_owned());
 
     let mut asm = ~"";
     let mut outputs = ~[];

src/libsyntax/ext/base.rs

@@ -22,7 +22,6 @@
 use parse::token::{ident_to_str, intern, str_to_ident};
 
 use core::hashmap::HashMap;
-use core::vec;
 
 // new-style macro! tt code:
 //
@@ -367,7 +366,7 @@ pub fn get_exprs_from_tts(cx: @ExtCtxt, tts: &[ast::token_tree])
                        -> ~[@ast::expr] {
     let p = parse::new_parser_from_tts(cx.parse_sess(),
                                        cx.cfg(),
-                                       vec::to_owned(tts));
+                                       tts.to_owned());
     let mut es = ~[];
     while *p.token != token::EOF {
         if es.len() != 0 {

src/libsyntax/ext/log_syntax.rs

@@ -18,7 +18,6 @@
 use parse::token::{get_ident_interner};
 
 use core::io;
-use core::vec;
 
 pub fn expand_syntax_ext(cx: @ExtCtxt,
                          sp: codemap::span,
@@ -28,7 +27,7 @@ pub fn expand_syntax_ext(cx: @ExtCtxt,
     cx.print_backtrace();
     io::stdout().write_line(
         print::pprust::tt_to_str(
-            ast::tt_delim(vec::to_owned(tt)),
+            ast::tt_delim(tt.to_owned()),
             get_ident_interner()));
 
     //trivial expression

src/libsyntax/ext/quote.rs

@@ -19,8 +19,6 @@
 use parse::token;
 use parse;
 
-use core::vec;
-
 /**
 *
 * Quasiquoting works via token trees.
@@ -40,8 +38,6 @@ pub mod rt {
     use parse;
     use print::pprust;
 
-    use core::str;
-
     pub use ast::*;
     pub use parse::token::*;
     pub use parse::new_parser_from_tts;
@@ -128,7 +124,7 @@ fn to_source(&self) -> ~str {
 
     impl<'self> ToSource for &'self str {
         fn to_source(&self) -> ~str {
-            let lit = dummy_spanned(ast::lit_str(@str::to_owned(*self)));
+            let lit = dummy_spanned(ast::lit_str(@self.to_owned()));
             pprust::lit_to_str(@lit)
         }
     }
@@ -661,7 +657,7 @@ fn expand_tts(cx: @ExtCtxt,
     let p = parse::new_parser_from_tts(
         cx.parse_sess(),
         cx.cfg(),
-        vec::to_owned(tts)
+        tts.to_owned()
     );
     *p.quote_depth += 1u;
     let tts = p.parse_all_token_trees();

src/libsyntax/ext/trace_macros.rs

@@ -18,8 +18,6 @@
 use parse::parser::Parser;
 use parse::token::keywords;
 
-use core::vec;
-
 pub fn expand_trace_macros(cx: @ExtCtxt,
                            sp: span,
                            tt: &[ast::token_tree])
@@ -29,7 +27,7 @@ pub fn expand_trace_macros(cx: @ExtCtxt,
     let tt_rdr = new_tt_reader(
         copy cx.parse_sess().span_diagnostic,
         None,
-        vec::to_owned(tt)
+        tt.to_owned()
     );
     let rdr = tt_rdr as @reader;
     let rust_parser = Parser(

src/libsyntax/ext/tt/macro_rules.rs

@@ -26,7 +26,6 @@
 use print;
 
 use core::io;
-use core::vec;
 
 pub fn add_new_extension(cx: @ExtCtxt,
                          sp: span,
@@ -84,7 +83,7 @@ fn generic_extension(cx: @ExtCtxt, sp: span, name: ident,
             io::println(fmt!("%s! { %s }",
                              cx.str_of(name),
                              print::pprust::tt_to_str(
-                                 ast::tt_delim(vec::to_owned(arg)),
+                                 ast::tt_delim(arg.to_owned()),
                                  get_ident_interner())));
         }
 
@@ -101,7 +100,7 @@ fn generic_extension(cx: @ExtCtxt, sp: span, name: ident,
                 let arg_rdr = new_tt_reader(
                     s_d,
                     None,
-                    vec::to_owned(arg)
+                    arg.to_owned()
                 ) as @reader;
                 match parse(cx.parse_sess(), cx.cfg(), arg_rdr, *mtcs) {
                   success(named_matches) => {

src/libsyntax/parse/token.rs

@@ -193,7 +193,7 @@ pub fn to_str(in: @ident_interner, t: &Token) -> ~str {
         }
         body
       }
-      LIT_STR(ref s) => { ~"\"" + str::escape_default(*ident_to_str(s)) + "\"" }
+      LIT_STR(ref s) => { ~"\"" + ident_to_str(s).escape_default() + "\"" }
 
       /* Name components */
       IDENT(s, _) => copy *in.get(s.name),

src/libsyntax/print/pprust.rs

@@ -31,7 +31,6 @@
 
 use core::char;
 use core::io;
-use core::str;
 use core::u64;
 use core::uint;
 use core::iterator::IteratorUtil;
@@ -2113,7 +2112,7 @@ pub fn print_comment(s: @ps, cmnt: &comments::cmnt) {
 
 pub fn print_string(s: @ps, st: &str) {
     word(s.s, "\"");
-    word(s.s, str::escape_default(st));
+    word(s.s, st.escape_default());
     word(s.s, "\"");
 }
 

src/test/bench/shootout-fasta-redux.rs

@@ -93,7 +93,7 @@ fn make(&mut self, n: uint) {
             let stdout = self.stdout;
             let alu_len = self.alu.len();
             let mut buf = vec::from_elem(alu_len + LINE_LEN, 0u8);
-            let alu: &[u8] = str::byte_slice_no_callback(self.alu);
+            let alu: &[u8] = self.alu.as_bytes_with_null();
 
             copy_memory(buf, alu, alu_len);
             copy_memory(vec::mut_slice(buf, alu_len, buf.len()),

src/test/bench/shootout-k-nucleotide-pipes.rs

@@ -81,7 +81,8 @@ fn sortKV<TT:Copy + Ord,UU:Copy + Ord>(orig: ~[(TT,UU)]) -> ~[(TT,UU)] {
 fn find(mm: &HashMap<~[u8], uint>, key: ~str) -> uint {
    // FIXME: #4318 Instead of to_ascii and to_str_ascii, could use
    // to_ascii_consume and to_str_consume to not do a unnecessary copy.
-   match mm.find(&str::to_bytes(key.to_ascii().to_lower().to_str_ascii())) {
+   let key = key.to_ascii().to_lower().to_str_ascii();
+   match mm.find_equiv(&key.as_bytes()) {
       option::None      => { return 0u; }
       option::Some(&num) => { return num; }
    }
@@ -208,10 +209,10 @@ fn main() {
 
          // process the sequence for k-mers
          (_, true) => {
-            let line_bytes = str::to_bytes(line);
+            let line_bytes = line.as_bytes();
 
            for sizes.eachi |ii, _sz| {
-               let mut lb = copy line_bytes;
+               let mut lb = line_bytes.to_owned();
                to_child[ii].send(lb);
             }
          }

src/test/bench/shootout-k-nucleotide.rs

@@ -218,8 +218,7 @@ fn read_stdin() -> ~[u8] {
         fstat(fileno(stdin), &mut st);
         let mut buf = vec::from_elem(st.st_size as uint, 0);
 
-        let header = str::byte_slice_no_callback(">THREE");
-        let header = vec::slice(header, 0, 6);
+        let header = ">THREE".as_bytes();
 
         {
             let mut window: &mut [u8] = buf;

src/test/bench/shootout-pfib.rs

@@ -111,8 +111,7 @@ fn main() {
     if opts.stress {
         stress(2);
     } else {
-        let max = uint::parse_bytes(str::to_bytes(args[1]),
-                                                10u).get() as int;
+        let max = uint::parse_bytes(args[1].as_bytes(), 10u).get() as int;
 
         let num_trials = 10;
 

src/test/run-pass/foreign-fn-linkname.rs

@@ -26,7 +26,7 @@ mod libc {
 fn strlen(str: ~str) -> uint {
     unsafe {
         // C string is terminated with a zero
-        let bytes = str::to_bytes(str) + ~[0u8];
+        let bytes = str.as_bytes_with_null_consume();
         return libc::my_strlen(vec::raw::to_ptr(bytes));
     }
 }

src/test/run-pass/hashmap-memory.rs

@@ -48,7 +48,7 @@ fn emit(im: &mut HashMap<~str, int>, ctrl: SharedChan<ctrl_proto>, key: ~str,
             }
             let (pp, cc) = stream();
             error!("sending find_reducer");
-            ctrl.send(find_reducer(str::to_bytes(key), cc));
+            ctrl.send(find_reducer(key.as_bytes().to_owned(), cc));
             error!("receiving");
             let c = pp.recv();
             error!(c);

src/test/run-pass/issue-1696.rs

@@ -15,6 +15,6 @@
 
 pub fn main() {
     let mut m = HashMap::new();
-    m.insert(str::to_bytes(~"foo"), str::to_bytes(~"bar"));
+    m.insert("foo".as_bytes().to_owned(), "bar".as_bytes().to_owned());
     error!(m);
 }

src/test/run-pass/struct-order-of-eval-1.rs

@@ -14,5 +14,5 @@ struct S { f0: ~str, f1: int }
 
 pub fn main() {
     let s = ~"Hello, world!";
-    let _s = S { f0: str::to_owned(s), ..S { f0: s, f1: 23 } };
+    let _s = S { f0: s.to_owned(), ..S { f0: s, f1: 23 } };
 }

src/test/run-pass/struct-order-of-eval-2.rs

@@ -14,5 +14,5 @@ struct S { f0: ~str, f1: ~str }
 
 pub fn main() {
     let s = ~"Hello, world!";
-    let _s = S { f1: str::to_owned(s), f0: s };
+    let _s = S { f1: s.to_owned(), f0: s };
 }

src/test/run-pass/utf8_chars.rs

@@ -21,24 +21,24 @@ pub fn main() {
     let schs: ~[char] = s.iter().collect();
 
     assert!(s.len() == 10u);
-    assert!(str::char_len(s) == 4u);
+    assert!(s.char_len() == 4u);
     assert!(schs.len() == 4u);
     assert!(str::from_chars(schs) == s);
     assert!(s.char_at(0u) == 'e');
     assert!(s.char_at(1u) == 'é');
 
-    assert!((str::is_utf8(str::to_bytes(s))));
+    assert!((str::is_utf8(s.as_bytes())));
     assert!((!str::is_utf8(~[0x80_u8])));
     assert!((!str::is_utf8(~[0xc0_u8])));
     assert!((!str::is_utf8(~[0xc0_u8, 0x10_u8])));
 
     let mut stack = ~"a×c€";
-    assert_eq!(str::pop_char(&mut stack), '€');
-    assert_eq!(str::pop_char(&mut stack), 'c');
+    assert_eq!(stack.pop_char(), '€');
+    assert_eq!(stack.pop_char(), 'c');
     stack.push_char('u');
     assert!(stack == ~"a×u");
-    assert_eq!(str::shift_char(&mut stack), 'a');
-    assert_eq!(str::shift_char(&mut stack), '×');
-    str::unshift_char(&mut stack, 'ß');
+    assert_eq!(stack.shift_char(), 'a');
+    assert_eq!(stack.shift_char(), '×');
+    stack.unshift_char('ß');
     assert!(stack == ~"ßu");
 }