syntax: Copy unstable str::char_at into libsyntax

3 files changed, 18 insertions, 16 deletions

diff --git a/src/libsyntax/parse/lexer/comments.rs b/src/libsyntax/parse/lexer/comments.rs
index 02f1a52aaf3..fb3a96f4c28 100644
--- a/src/libsyntax/parse/lexer/comments.rs
+++ b/src/libsyntax/parse/lexer/comments.rs
@@ -13,11 +13,12 @@ pub use self::CommentStyle::*;
 use ast;
 use codemap::{BytePos, CharPos, CodeMap, Pos};
 use diagnostic;
-use parse::lexer::{is_whitespace, Reader};
-use parse::lexer::{StringReader, TokenAndSpan};
 use parse::lexer::is_block_doc_comment;
+use parse::lexer::{StringReader, TokenAndSpan};
+use parse::lexer::{is_whitespace, Reader};
 use parse::lexer;
 use print::pprust;
+use str::char_at;
 
 use std::io::Read;
 use std::usize;
@@ -209,7 +210,7 @@ fn all_whitespace(s: &str, col: CharPos) -> Option<usize> {
     let mut col = col.to_usize();
     let mut cursor: usize = 0;
     while col > 0 && cursor < len {
-        let ch = s.char_at(cursor);
+        let ch = char_at(s, cursor);
         if !ch.is_whitespace() {
             return None;
         }
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index 9cd3db45784..8e37b983e21 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -13,8 +13,9 @@ use codemap::{BytePos, CharPos, CodeMap, Pos, Span};
 use codemap;
 use diagnostic::SpanHandler;
 use ext::tt::transcribe::tt_next_token;
-use parse::token;
 use parse::token::str_to_ident;
+use parse::token;
+use str::char_at;
 
 use std::borrow::Cow;
 use std::char;
@@ -289,10 +290,10 @@ impl<'a> StringReader<'a> {
                           s: &'b str, errmsg: &'b str) -> Cow<'b, str> {
         let mut i = 0;
         while i < s.len() {
-            let ch = s.char_at(i);
+            let ch = char_at(s, i);
             let next = i + ch.len_utf8();
             if ch == '\r' {
-                if next < s.len() && s.char_at(next) == '\n' {
+                if next < s.len() && char_at(s, next) == '\n' {
                     return translate_crlf_(self, start, s, errmsg, i).into();
                 }
                 let pos = start + BytePos(i as u32);
@@ -308,12 +309,12 @@ impl<'a> StringReader<'a> {
             let mut buf = String::with_capacity(s.len());
             let mut j = 0;
             while i < s.len() {
-                let ch = s.char_at(i);
+                let ch = char_at(s, i);
                 let next = i + ch.len_utf8();
                 if ch == '\r' {
                     if j < i { buf.push_str(&s[j..i]); }
                     j = next;
-                    if next >= s.len() || s.char_at(next) != '\n' {
+                    if next >= s.len() || char_at(s, next) != '\n' {
                         let pos = start + BytePos(i as u32);
                         let end_pos = start + BytePos(next as u32);
                         rdr.err_span_(pos, end_pos, errmsg);
@@ -335,7 +336,7 @@ impl<'a> StringReader<'a> {
         if current_byte_offset < self.source_text.len() {
             assert!(self.curr.is_some());
             let last_char = self.curr.unwrap();
-            let ch = self.source_text.char_at(current_byte_offset);
+            let ch = char_at(&self.source_text, current_byte_offset);
             let next = current_byte_offset + ch.len_utf8();
             let byte_offset_diff = next - current_byte_offset;
             self.pos = self.pos + Pos::from_usize(byte_offset_diff);
@@ -357,7 +358,7 @@ impl<'a> StringReader<'a> {
     pub fn nextch(&self) -> Option<char> {
         let offset = self.byte_offset(self.pos).to_usize();
         if offset < self.source_text.len() {
-            Some(self.source_text.char_at(offset))
+            Some(char_at(&self.source_text, offset))
         } else {
             None
         }
@@ -371,9 +372,9 @@ impl<'a> StringReader<'a> {
         let offset = self.byte_offset(self.pos).to_usize();
         let s = &self.source_text[..];
         if offset >= s.len() { return None }
-        let next = offset + s.char_at(offset).len_utf8();
+        let next = offset + char_at(s, offset).len_utf8();
         if next < s.len() {
-            Some(s.char_at(next))
+            Some(char_at(s, next))
         } else {
             None
         }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 51fb09a7526..1333e27058f 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -16,7 +16,7 @@ use diagnostic::{SpanHandler, mk_span_handler, default_handler, Auto, FatalError
 use parse::attr::ParserAttr;
 use parse::parser::Parser;
 use ptr::P;
-
+use str::char_at;
 
 use std::cell::{Cell, RefCell};
 use std::fs::File;
@@ -536,7 +536,7 @@ pub fn raw_str_lit(lit: &str) -> String {
 // check if `s` looks like i32 or u1234 etc.
 fn looks_like_width_suffix(first_chars: &[char], s: &str) -> bool {
     s.len() > 1 &&
-        first_chars.contains(&s.char_at(0)) &&
+        first_chars.contains(&char_at(s, 0)) &&
         s[1..].chars().all(|c| '0' <= c && c <= '9')
 }
 
@@ -673,8 +673,8 @@ pub fn integer_lit(s: &str, suffix: Option<&str>, sd: &SpanHandler, sp: Span) ->
     let orig = s;
     let mut ty = ast::UnsuffixedIntLit(ast::Plus);
 
-    if s.char_at(0) == '0' && s.len() > 1 {
-        match s.char_at(1) {
+    if char_at(s, 0) == '0' && s.len() > 1 {
+        match char_at(s, 1) {
             'x' => base = 16,
             'o' => base = 8,
             'b' => base = 2,