initial draft of fix for issue #2498:

1. make /// ... and //! ... and /** ... */ and /*! ... */ into sugar for #[doc = ...] attributes.
2. add a script in etc/ to help converting doc-attributes to doc-comments
3. add some functions to core::str to help with (1)

src/etc/sugarise-doc-comments.py

+#!/usr/bin/python
+
+#
+# this script attempts to turn doc comment attributes (#[doc = "..."])
+# into sugared-doc-comments (/** ... */ and /// ...)
+#
+# it sugarises all .rs/.rc files underneath the working directory
+#
+
+import sys, os, fnmatch, re
+
+
+DOC_PATTERN = '^(?P<indent>[\\t ]*)#\\[(\\s*)doc(\\s*)=' + \
+              '(\\s*)"(?P<text>(\\"|[^"])*?)"(\\s*)\\]' + \
+              '(?P<semi>;)?'
+
+ESCAPES = [("\\'", "'"),
+           ('\\"', '"'),
+           ("\\n", "\n"),
+           ("\\r", "\r"),
+           ("\\t", "\t")]
+
+
+def unescape(s):
+    for (find, repl) in ESCAPES:
+        s = s.replace(find, repl)
+    return s
+
+
+def block_trim(s):
+    lns = s.splitlines()
+
+    # remove leading/trailing whitespace-lines
+    while lns and not lns[0].strip():
+        lns = lns[1:]
+    while lns and not lns[-1].strip():
+        lns = lns[:-1]
+
+    # remove leading horizontal whitespace
+    n = sys.maxint
+    for ln in lns:
+        if ln.strip():
+            n = min(n, len(re.search('^\s*', ln).group()))
+    if n != sys.maxint:
+        lns = [ln[n:] for ln in lns]
+
+    # strip trailing whitespace
+    lns = [ln.rstrip() for ln in lns]
+
+    return lns
+
+
+def replace_doc(m):
+    indent = m.group('indent')
+    text = block_trim(unescape(m.group('text')))
+
+    if len(text) > 1:
+        inner = '!' if m.group('semi') else '*'
+        starify = lambda s: indent + ' *' + (' ' + s if s else '')
+        text = '\n'.join(map(starify, text))
+        repl = indent + '/*' + inner + '\n' + text + '\n' + indent + ' */'
+    else:
+        inner = '!' if m.group('semi') else '/'
+        repl = indent + '//' + inner + ' ' + text[0]
+
+    return repl
+
+
+def sugarise_file(path):
+    s = open(path).read()
+
+    r = re.compile(DOC_PATTERN, re.MULTILINE | re.DOTALL)
+    ns = re.sub(r, replace_doc, s)
+
+    if s != ns:
+        open(path, 'w').write(ns)
+
+
+for (dirpath, dirnames, filenames) in os.walk('.'):
+    for name in fnmatch.filter(filenames, '*.r[sc]'):
+        sugarise_file(os.path.join(dirpath, name))
+

src/libcore/str.rs

@@ -58,8 +58,8 @@
    all, any,
    all_between, any_between,
    map,
-   each,
-   each_char,
+   each, eachi,
+   each_char, each_chari,
    bytes_iter,
    chars_iter,
    split_char_iter,
@@ -73,7 +73,7 @@
    find_char, find_char_from, find_char_between,
    rfind_char, rfind_char_from, rfind_char_between,
    find_str, find_str_from, find_str_between,
-   contains,
+   contains, contains_char,
    starts_with,
    ends_with,
 
@@ -672,9 +672,15 @@ fn shift_char(&s: str) -> char {
 #[doc = "Iterate over the bytes in a string"]
 #[inline(always)]
 pure fn each(s: str/&, it: fn(u8) -> bool) {
+    eachi(s, {|_i, b| it(b)})
+}
+
+#[doc = "Iterate over the bytes in a string, with indices"]
+#[inline(always)]
+pure fn eachi(s: str/&, it: fn(uint, u8) -> bool) {
     let mut i = 0u, l = len(s);
     while (i < l) {
-        if !it(s[i]) { break; }
+        if !it(i, s[i]) { break; }
         i += 1u;
     }
 }
@@ -682,12 +688,19 @@ fn shift_char(&s: str) -> char {
 #[doc = "Iterates over the chars in a string"]
 #[inline(always)]
 pure fn each_char(s: str/&, it: fn(char) -> bool) {
-    let mut pos = 0u;
+    each_chari(s, {|_i, c| it(c)})
+}
+
+#[doc = "Iterates over the chars in a string, with indices"]
+#[inline(always)]
+pure fn each_chari(s: str/&, it: fn(uint, char) -> bool) {
+    let mut pos = 0u, ch_pos = 0u;
     let len = len(s);
     while pos < len {
         let {ch, next} = char_range_at(s, pos);
         pos = next;
-        if !it(ch) { break; }
+        if !it(ch_pos, ch) { break; }
+        ch_pos += 1u;
     }
 }
 
@@ -1146,6 +1159,18 @@ fn shift_char(&s: str) -> char {
     option::is_some(find_str(haystack, needle))
 }
 
+#[doc = "
+Returns true if a string contains a char.
+
+# Arguments
+
+* haystack - The string to look in
+* needle - The char to look for
+"]
+pure fn contains_char(haystack: str/&, needle: char) -> bool {
+    option::is_some(find_char(haystack, needle))
+}
+
 #[doc = "
 Returns true if one string starts with another
 
@@ -1879,12 +1904,21 @@ fn any(it: fn(char) -> bool) -> bool { any(self, it) }
     #[doc = "Returns true if one string contains another"]
     #[inline]
     fn contains(needle: str/&a) -> bool { contains(self, needle) }
+    #[doc = "Returns true if a string contains a char"]
+    #[inline]
+    fn contains_char(needle: char) -> bool { contains_char(self, needle) }
     #[doc = "Iterate over the bytes in a string"]
     #[inline]
     fn each(it: fn(u8) -> bool) { each(self, it) }
+    #[doc = "Iterate over the bytes in a string, with indices"]
+    #[inline]
+    fn eachi(it: fn(uint, u8) -> bool) { eachi(self, it) }
     #[doc = "Iterate over the chars in a string"]
     #[inline]
     fn each_char(it: fn(char) -> bool) { each_char(self, it) }
+    #[doc = "Iterate over the chars in a string, with indices"]
+    #[inline]
+    fn each_chari(it: fn(uint, char) -> bool) { each_chari(self, it) }
     #[doc = "Returns true if one string ends with another"]
     #[inline]
     fn ends_with(needle: str/&) -> bool { ends_with(self, needle) }
@@ -2644,6 +2678,14 @@ fn test_contains() {
         assert !contains(data, "ไท华");
     }
 
+    #[test]
+    fn test_contains_char() {
+        assert contains_char("abc", 'b');
+        assert contains_char("a", 'a');
+        assert !contains_char("abc", 'd');
+        assert !contains_char("", 'a');
+    }
+
     #[test]
     fn test_chars_iter() {
         let mut i = 0;

src/libsyntax/ast.rs

@@ -652,8 +652,9 @@ enum view_item_ {
 #[auto_serialize]
 enum attr_style { attr_outer, attr_inner, }
 
+// doc-comments are promoted to attributes that have is_sugared_doc = true
 #[auto_serialize]
-type attribute_ = {style: attr_style, value: meta_item};
+type attribute_ = {style: attr_style, value: meta_item, is_sugared_doc: bool};
 
 /*
   iface_refs appear in both impls and in classes that implement ifaces.

src/libsyntax/attr.rs

@@ -4,7 +4,8 @@
 import std::map::hashmap;
 import either::either;
 import diagnostic::span_handler;
-import ast_util::dummy_spanned;
+import ast_util::{spanned, dummy_spanned};
+import parse::comments::{doc_comment_style, strip_doc_comment_decoration};
 
 // Constructors
 export mk_name_value_item_str;
@@ -12,10 +13,12 @@
 export mk_list_item;
 export mk_word_item;
 export mk_attr;
+export mk_sugared_doc_attr;
 
 // Conversion
 export attr_meta;
 export attr_metas;
+export desugar_doc_attr;
 
 // Accessors
 export get_attr_name;
@@ -66,9 +69,19 @@ fn mk_word_item(+name: ast::ident) -> @ast::meta_item {
 }
 
 fn mk_attr(item: @ast::meta_item) -> ast::attribute {
-    ret dummy_spanned({style: ast::attr_inner, value: *item});
+    ret dummy_spanned({style: ast::attr_inner, value: *item,
+                       is_sugared_doc: false});
 }
 
+fn mk_sugared_doc_attr(text: str, lo: uint, hi: uint) -> ast::attribute {
+    let lit = spanned(lo, hi, ast::lit_str(@text));
+    let attr = {
+        style: doc_comment_style(text),
+        value: spanned(lo, hi, ast::meta_name_value(@"doc", lit)),
+        is_sugared_doc: true
+    };
+    ret spanned(lo, hi, attr);
+}
 
 /* Conversion */
 
@@ -81,6 +94,16 @@ fn attr_metas(attrs: [ast::attribute]/~) -> [@ast::meta_item]/~ {
     ret mitems;
 }
 
+fn desugar_doc_attr(attr: ast::attribute) -> ast::attribute {
+    if attr.node.is_sugared_doc {
+        let comment = get_meta_item_value_str(@attr.node.value).get();
+        let meta = mk_name_value_item_str(@"doc",
+                                     strip_doc_comment_decoration(*comment));
+        ret mk_attr(meta);
+    } else {
+        attr
+    }
+}
 
 /* Accessors */
 

src/libsyntax/fold.rs

@@ -102,7 +102,8 @@ fn fold_meta_item_(&&mi: @meta_item, fld: ast_fold) -> @meta_item {
 fn fold_attribute_(at: attribute, fld: ast_fold) ->
    attribute {
     ret {node: {style: at.node.style,
-                value: *fold_meta_item_(@at.node.value, fld)},
+                value: *fold_meta_item_(@at.node.value, fld),
+                is_sugared_doc: at.node.is_sugared_doc },
          span: fld.new_span(at.span)};
 }
 //used in noop_fold_foreign_item and noop_fold_fn_decl

src/libsyntax/parse/attr.rs

@@ -15,7 +15,8 @@ fn parse_outer_attrs_or_ext(first_item_attrs: [ast::attribute]/~)
         -> attr_or_ext
     {
         let expect_item_next = vec::is_not_empty(first_item_attrs);
-        if self.token == token::POUND {
+        alt self.token {
+          token::POUND {
             let lo = self.span.lo;
             if self.look_ahead(1u) == token::LBRACKET {
                 self.bump();
@@ -30,15 +31,40 @@ fn parse_outer_attrs_or_ext(first_item_attrs: [ast::attribute]/~)
                 self.bump();
                 ret some(right(self.parse_syntax_ext_naked(lo)));
             } else { ret none; }
-        } else { ret none; }
+        }
+        token::DOC_COMMENT(_) {
+          ret some(left(self.parse_outer_attributes()));
+        }
+        _ {
+          ret none;
+        }
+      }
     }
 
     // Parse attributes that appear before an item
     fn parse_outer_attributes() -> [ast::attribute]/~ {
         let mut attrs: [ast::attribute]/~ = []/~;
-        while self.token == token::POUND
-            && self.look_ahead(1u) == token::LBRACKET {
-            vec::push(attrs, self.parse_attribute(ast::attr_outer));
+        loop {
+            alt copy self.token {
+              token::POUND {
+                if self.look_ahead(1u) != token::LBRACKET {
+                    break;
+                }
+                attrs += [self.parse_attribute(ast::attr_outer)]/~;
+              }
+              token::DOC_COMMENT(s) {
+                let attr = ::attr::mk_sugared_doc_attr(
+                        *self.get_str(s), self.span.lo, self.span.hi);
+                if attr.node.style != ast::attr_outer {
+                  self.fatal("expected outer comment");
+                }
+                attrs += [attr]/~;
+                self.bump();
+              }
+              _ {
+                break;
+              }
+            }
         }
         ret attrs;
     }
@@ -55,7 +81,8 @@ fn parse_attribute_naked(style: ast::attr_style, lo: uint) ->
         let meta_item = self.parse_meta_item();
         self.expect(token::RBRACKET);
         let mut hi = self.span.hi;
-        ret spanned(lo, hi, {style: style, value: *meta_item});
+        ret spanned(lo, hi, {style: style, value: *meta_item,
+                             is_sugared_doc: false});
     }
 
     // Parse attributes that appear after the opening of an item, each
@@ -68,7 +95,9 @@ fn parse_inner_attrs_and_next() ->
         {inner: [ast::attribute]/~, next: [ast::attribute]/~} {
         let mut inner_attrs: [ast::attribute]/~ = []/~;
         let mut next_outer_attrs: [ast::attribute]/~ = []/~;
-        while self.token == token::POUND {
+        loop {
+            alt copy self.token {
+              token::POUND {
                 if self.look_ahead(1u) != token::LBRACKET {
                     // This is an extension
                     break;
@@ -76,16 +105,33 @@ fn parse_inner_attrs_and_next() ->
                 let attr = self.parse_attribute(ast::attr_inner);
                 if self.token == token::SEMI {
                     self.bump();
-                vec::push(inner_attrs, attr);
+                    inner_attrs += [attr]/~;
                 } else {
                     // It's not really an inner attribute
                     let outer_attr =
                         spanned(attr.span.lo, attr.span.hi,
-                            {style: ast::attr_outer, value: attr.node.value});
-                vec::push(next_outer_attrs, outer_attr);
+                            {style: ast::attr_outer, value: attr.node.value,
+                             is_sugared_doc: false});
+                    next_outer_attrs += [outer_attr]/~;
+                    break;
+                }
+              }
+              token::DOC_COMMENT(s) {
+                let attr = ::attr::mk_sugared_doc_attr(
+                        *self.get_str(s), self.span.lo, self.span.hi);
+                self.bump();
+                if attr.node.style == ast::attr_inner {
+                  inner_attrs += [attr]/~;
+                } else {
+                  next_outer_attrs += [attr]/~;
                   break;
                 }
               }
+              _ {
+                break;
+              }
+            }
+        }
         ret {inner: inner_attrs, next: next_outer_attrs};
     }
 

src/libsyntax/parse/comments.rs

@@ -8,6 +8,7 @@
 export lit;
 export cmnt_style;
 export gather_comments_and_literals;
+export is_doc_comment, doc_comment_style, strip_doc_comment_decoration;
 
 enum cmnt_style {
     isolated, // No code on either side of each line of the comment
@@ -18,6 +19,81 @@ enum cmnt_style {
 
 type cmnt = {style: cmnt_style, lines: [str]/~, pos: uint};
 
+fn is_doc_comment(s: str) -> bool {
+    s.starts_with("///") ||
+    s.starts_with("//!") ||
+    s.starts_with("/**") ||
+    s.starts_with("/*!")
+}
+
+fn doc_comment_style(comment: str) -> ast::attr_style {
+    assert is_doc_comment(comment);
+    if comment.starts_with("//!") || comment.starts_with("/*!") {
+        ast::attr_inner
+    } else {
+        ast::attr_outer
+    }
+}
+
+fn strip_doc_comment_decoration(comment: str) -> str {
+
+    /// remove whitespace-only lines from the start/end of lines
+    fn vertical_trim(lines: [str]/~) -> [str]/~ {
+        let mut i = 0u, j = lines.len();
+        while i < j && lines[i].trim().is_empty() {
+            i += 1u;
+        }
+        while j > i && lines[j - 1u].trim().is_empty() {
+            j -= 1u;
+        }
+        ret lines.slice(i, j);
+    }
+
+    // drop leftmost columns that contain only values in chars
+    fn block_trim(lines: [str]/~, chars: str, max: option<uint>) -> [str]/~ {
+
+        let mut i = max.get_default(uint::max_value);
+        for lines.each {|line|
+            if line.trim().is_empty() {
+                cont;
+            }
+            for line.each_chari {|j, c|
+                if j >= i {
+                    break;
+                }
+                if !chars.contains_char(c) {
+                    i = j;
+                    break;
+                }
+            }
+        }
+
+        ret lines.map {|line|
+            let chars = str::chars(line);
+            if i > chars.len() {
+                ""
+            } else {
+                str::from_chars(chars.slice(i, chars.len()))
+            }
+        };
+    }
+
+    if comment.starts_with("//") {
+        ret comment.slice(3u, comment.len()).trim();
+    }
+
+    if comment.starts_with("/*") {
+        let lines = str::lines_any(comment.slice(3u, comment.len() - 2u));
+        let lines = vertical_trim(lines);
+        let lines = block_trim(lines, "\t ", none);
+        let lines = block_trim(lines, "*", some(1u));
+        let lines = block_trim(lines, "\t ", none);
+        ret str::connect(lines, "\n");
+    }
+
+    fail "not a doc-comment: " + comment;
+}
+
 fn read_to_eol(rdr: string_reader) -> str {
     let mut val = "";
     while rdr.curr != '\n' && !is_eof(rdr) {
@@ -57,29 +133,41 @@ fn consume_whitespace_counting_blank_lines(rdr: string_reader,
     }
 }
 
-fn read_shebang_comment(rdr: string_reader, code_to_the_left: bool) -> cmnt {
+
+fn read_shebang_comment(rdr: string_reader, code_to_the_left: bool,
+                                                        &comments: [cmnt]/~) {
     #debug(">>> shebang comment");
     let p = rdr.chpos;
     #debug("<<< shebang comment");
-    ret {style: if code_to_the_left { trailing } else { isolated },
+    vec::push(comments, {
+        style: if code_to_the_left { trailing } else { isolated },
         lines: [read_one_line_comment(rdr)]/~,
-         pos: p};
+        pos: p
+    });
 }
 
-fn read_line_comments(rdr: string_reader, code_to_the_left: bool) -> cmnt {
+fn read_line_comments(rdr: string_reader, code_to_the_left: bool,
+                                                        &comments: [cmnt]/~) {
     #debug(">>> line comments");
     let p = rdr.chpos;
     let mut lines: [str]/~ = []/~;
     while rdr.curr == '/' && nextch(rdr) == '/' {
         let line = read_one_line_comment(rdr);
         log(debug, line);
+        if is_doc_comment(line) { // doc-comments are not put in comments
+            break;
+        }
         vec::push(lines, line);
         consume_non_eol_whitespace(rdr);
     }
     #debug("<<< line comments");
-    ret {style: if code_to_the_left { trailing } else { isolated },
+    if !lines.is_empty() {
+        vec::push(comments, {
+            style: if code_to_the_left { trailing } else { isolated },
             lines: lines,
-         pos: p};
+            pos: p
+        });
+    }
 }
 
 fn all_whitespace(s: str, begin: uint, end: uint) -> bool {
@@ -101,13 +189,27 @@ fn trim_whitespace_prefix_and_push_line(&lines: [str]/~,
     vec::push(lines, s1);
 }
 
-fn read_block_comment(rdr: string_reader, code_to_the_left: bool) -> cmnt {
+fn read_block_comment(rdr: string_reader, code_to_the_left: bool,
+                                                        &comments: [cmnt]/~) {
     #debug(">>> block comment");
     let p = rdr.chpos;
     let mut lines: [str]/~ = []/~;
     let mut col: uint = rdr.col;
     bump(rdr);
     bump(rdr);
+
+    // doc-comments are not really comments, they are attributes
+    if rdr.curr == '*' || rdr.curr == '!' {
+        while !(rdr.curr == '*' && nextch(rdr) == '/') && !is_eof(rdr) {
+            bump(rdr);
+        }
+        if !is_eof(rdr) {
+            bump(rdr);
+            bump(rdr);
+        }
+        ret;
+    }
+
     let mut curr_line = "/*";
     let mut level: int = 1;
     while level > 0 {
@@ -143,7 +245,7 @@ fn read_block_comment(rdr: string_reader, code_to_the_left: bool) -> cmnt {
         style = mixed;
     }
     #debug("<<< block comment");
-    ret {style: style, lines: lines, pos: p};
+    vec::push(comments, {style: style, lines: lines, pos: p});
 }
 
 fn peeking_at_comment(rdr: string_reader) -> bool {
@@ -156,11 +258,11 @@ fn consume_comment(rdr: string_reader, code_to_the_left: bool,
                    &comments: [cmnt]/~) {
     #debug(">>> consume comment");
     if rdr.curr == '/' && nextch(rdr) == '/' {
-        vec::push(comments, read_line_comments(rdr, code_to_the_left));
+        read_line_comments(rdr, code_to_the_left, comments);
     } else if rdr.curr == '/' && nextch(rdr) == '*' {
-        vec::push(comments, read_block_comment(rdr, code_to_the_left));
+        read_block_comment(rdr, code_to_the_left, comments);
     } else if rdr.curr == '#' && nextch(rdr) == '!' {
-        vec::push(comments, read_shebang_comment(rdr, code_to_the_left));
+        read_shebang_comment(rdr, code_to_the_left, comments);
     } else { fail; }
     #debug("<<< consume comment");
 }

src/libsyntax/parse/lexer.rs

@@ -161,7 +161,11 @@ fn dup() -> reader { dup_tt_reader(self) as reader }
 }
 
 fn string_advance_token(&&r: string_reader) {
-    consume_whitespace_and_comments(r);
+    for consume_whitespace_and_comments(r).each {|comment|
+        r.peek_tok = comment.tok;
+        r.peek_span = comment.sp;
+        ret;
+    }
 
     if is_eof(r) {
         r.peek_tok = token::EOF;
@@ -277,22 +281,41 @@ fn is_hex_digit(c: char) -> bool {
 
 fn is_bin_digit(c: char) -> bool { ret c == '0' || c == '1'; }
 
-fn consume_whitespace_and_comments(rdr: string_reader) {
+// might return a sugared-doc-attr
+fn consume_whitespace_and_comments(rdr: string_reader)
+                                -> option<{tok: token::token, sp: span}> {
     while is_whitespace(rdr.curr) { bump(rdr); }
     ret consume_any_line_comment(rdr);
 }
 
-fn consume_any_line_comment(rdr: string_reader) {
+// might return a sugared-doc-attr
+fn consume_any_line_comment(rdr: string_reader)
+                                -> option<{tok: token::token, sp: span}> {
     if rdr.curr == '/' {
         alt nextch(rdr) {
           '/' {
+            bump(rdr);
+            bump(rdr);
+            // line comments starting with "///" or "//!" are doc-comments
+            if rdr.curr == '/' || rdr.curr == '!' {
+                let start_chpos = rdr.chpos - 2u;
+                let mut acc = "//";
+                while rdr.curr != '\n' && !is_eof(rdr) {
+                    str::push_char(acc, rdr.curr);
+                    bump(rdr);
+                }
+                ret some({
+                    tok: token::DOC_COMMENT(intern(*rdr.interner, @acc)),
+                    sp: ast_util::mk_sp(start_chpos, rdr.chpos)
+                });
+            } else {
                 while rdr.curr != '\n' && !is_eof(rdr) { bump(rdr); }
                 // Restart whitespace munch.
-
                 ret consume_whitespace_and_comments(rdr);
             }
+          }
           '*' { bump(rdr); bump(rdr); ret consume_block_comment(rdr); }
-          _ { ret; }
+          _ {}
         }
     } else if rdr.curr == '#' {
         if nextch(rdr) == '!' {
@@ -305,9 +328,34 @@ fn consume_any_line_comment(rdr: string_reader) {
             }
         }
     }
+    ret none;
 }
 
-fn consume_block_comment(rdr: string_reader) {
+// might return a sugared-doc-attr
+fn consume_block_comment(rdr: string_reader)
+                                -> option<{tok: token::token, sp: span}> {
+
+    // block comments starting with "/**" or "/*!" are doc-comments
+    if rdr.curr == '*' || rdr.curr == '!' {
+        let start_chpos = rdr.chpos - 2u;
+        let mut acc = "/*";
+        while !(rdr.curr == '*' && nextch(rdr) == '/') && !is_eof(rdr) {
+            str::push_char(acc, rdr.curr);
+            bump(rdr);
+        }
+        if is_eof(rdr) {
+            rdr.fatal("unterminated block doc-comment");
+        } else {
+            acc += "*/";
+            bump(rdr);
+            bump(rdr);
+            ret some({
+                tok: token::DOC_COMMENT(intern(*rdr.interner, @acc)),
+                sp: ast_util::mk_sp(start_chpos, rdr.chpos)
+            });
+        }
+    }
+
     let mut level: int = 1;
     while level > 0 {
         if is_eof(rdr) { rdr.fatal("unterminated block comment"); }

src/libsyntax/parse/token.rs

@@ -80,6 +80,7 @@ enum token {
 
     //ACTUALLY(whole_nonterminal),
 
+    DOC_COMMENT(str_num),
     EOF,
 }
 
@@ -170,11 +171,15 @@ fn to_str(in: interner<@str>, t: token) -> str {
             + str::escape_default(*interner::get(in, s))
             + "\""
       }
+
       /* Name components */
       IDENT(s, _) {
         *interner::get(in, s)
       }
       UNDERSCORE { "_" }
+
+      /* Other */
+      DOC_COMMENT(s) { *interner::get(in, s) }
       EOF { "<eof>" }
     }
 }

src/libsyntax/print/pprust.rs

@@ -647,7 +647,9 @@ fn print_inner_attributes(s: ps, attrs: [ast::attribute]/~) {
         alt attr.node.style {
           ast::attr_inner {
             print_attribute(s, attr);
+            if !attr.node.is_sugared_doc {
                 word(s.s, ";");
+            }
             count += 1;
           }
           _ {/* fallthrough */ }
@@ -659,9 +661,15 @@ fn print_inner_attributes(s: ps, attrs: [ast::attribute]/~) {
 fn print_attribute(s: ps, attr: ast::attribute) {
     hardbreak_if_not_bol(s);
     maybe_print_comment(s, attr.span.lo);
+    if attr.node.is_sugared_doc {
+        let meta = attr::attr_meta(attr);
+        let comment = attr::get_meta_item_value_str(meta).get();
+        word(s.s, *comment);
+    } else {
         word(s.s, "#[");
         print_meta_item(s, @attr.node.value);
         word(s.s, "]");
+    }
 }
 
 

src/rustc/driver/session.rs

@@ -233,7 +233,8 @@ fn make_crate_type_attr(t: str) -> ast::attribute {
                 ast::meta_name_value(
                     @"crate_type",
                     ast_util::respan(ast_util::dummy_sp(),
-                                     ast::lit_str(@t))))
+                                     ast::lit_str(@t)))),
+            is_sugared_doc: false
         })
     }
 

src/rustc/metadata/decoder.rs

@@ -612,7 +612,8 @@ fn get_attributes(md: ebml::doc) -> [ast::attribute]/~ {
             assert (vec::len(meta_items) == 1u);
             let meta_item = meta_items[0];
             vec::push(attrs,
-                      {node: {style: ast::attr_outer, value: *meta_item},
+                      {node: {style: ast::attr_outer, value: *meta_item,
+                              is_sugared_doc: false},
                        span: ast_util::dummy_sp()});
         };
       }

src/rustdoc/attr_parser.rs

@@ -44,7 +44,10 @@ fn doc_meta(
        doc attribute"];
 
     let doc_attrs = attr::find_attrs_by_name(attrs, "doc");
-    let doc_metas = attr::attr_metas(doc_attrs);
+    let doc_metas = doc_attrs.map {|attr|
+        attr::attr_meta(attr::desugar_doc_attr(attr))
+    };
+
     if vec::is_not_empty(doc_metas) {
         if vec::len(doc_metas) != 1u {
             #warn("ignoring %u doc attributes", vec::len(doc_metas) - 1u);

src/test/pretty/doc-comments.rs

+// pp-exact
+
+// some single-line non-doc comment
+
+/// some single line outer-docs
+fn a() { }
+
+fn b() {
+    //! some single line inner-docs
+}
+
+/*
+ * some multi-line non-doc comment
+ */
+
+/**
+ * some multi-line outer-docs
+ */
+fn c() { }
+
+fn d() {
+    /*!
+     * some multi-line inner-docs
+     */
+}
+
+#[doc = "unsugared outer doc-comments work also"]
+fn e() { }
+
+fn f() {
+    #[doc = "as do inner ones"];
+}