auto merge of #16689 : wickerwaka/rust/crate-as, r=pcwalton

For review. Not sure about the link_attrs stuff. Will work on converting all the tests.

extern crate "foobar" as foo;
extern crate foobar as foo;

Implements remaining part of RFC #47.
Addresses issue #16461.

Removed link_attrs from rust.md, they don't appear to be supported by
the parser.

Author: bors

src/doc/rust.md

@@ -891,9 +891,8 @@ There are several kinds of view item:
 ##### Extern crate declarations
 
 ~~~~ {.ebnf .gram}
-extern_crate_decl : "extern" "crate" ident [ '(' link_attrs ')' ] ? [ '=' string_lit ] ? ;
-link_attrs : link_attr [ ',' link_attrs ] + ;
-link_attr : ident '=' literal ;
+extern_crate_decl : "extern" "crate" crate_name
+crate_name: ident | ( string_lit as ident )
 ~~~~
 
 An _`extern crate` declaration_ specifies a dependency on an external crate.
@@ -913,11 +912,9 @@ Four examples of `extern crate` declarations:
 ~~~~ {.ignore}
 extern crate pcre;
 
-extern crate std; // equivalent to: extern crate std = "std";
+extern crate std; // equivalent to: extern crate std as std;
 
-extern crate ruststd = "std"; // linking to 'std' under another name
-
-extern crate foo = "some/where/rust-foo#foo:1.0"; // a full crate ID for external tools
+extern crate "std" as ruststd; // linking to 'std' under another name
 ~~~~
 
 ##### Use declarations

src/libsyntax/parse/parser.rs

@@ -4807,7 +4807,8 @@ impl<'a> Parser<'a> {
     /// # Example
     ///
     /// extern crate url;
-    /// extern crate foo = "bar";
+    /// extern crate foo = "bar"; //deprecated
+    /// extern crate "bar" as foo;
     fn parse_item_extern_crate(&mut self,
                                 lo: BytePos,
                                 visibility: Visibility,
@@ -4818,14 +4819,23 @@ impl<'a> Parser<'a> {
             token::IDENT(..) => {
                 let the_ident = self.parse_ident();
                 self.expect_one_of(&[], &[token::EQ, token::SEMI]);
+                // NOTE - #16689 change this to a warning once
+                //        the 'as' support is in stage0
                 let path = if self.token == token::EQ {
                     self.bump();
                     Some(self.parse_str())
                 } else {None};
 
                 self.expect(&token::SEMI);
                 (path, the_ident)
-            }
+            },
+            token::LIT_STR(..) | token::LIT_STR_RAW(..) => {
+                let path = self.parse_str();
+                self.expect_keyword(keywords::As);
+                let the_ident = self.parse_ident();
+                self.expect(&token::SEMI);
+                (Some(path), the_ident)
+            },
             _ => {
                 let span = self.span;
                 let token_str = self.this_token_to_string();

src/libsyntax/print/pprust.rs

@@ -2363,13 +2363,13 @@ impl<'a> State<'a> {
         match item.node {
             ast::ViewItemExternCrate(id, ref optional_path, _) => {
                 try!(self.head("extern crate"));
-                try!(self.print_ident(id));
                 for &(ref p, style) in optional_path.iter() {
+                    try!(self.print_string(p.get(), style));
                     try!(space(&mut self.s));
-                    try!(word(&mut self.s, "="));
+                    try!(word(&mut self.s, "as"));
                     try!(space(&mut self.s));
-                    try!(self.print_string(p.get(), style));
                 }
+                try!(self.print_ident(id));
             }
 
             ast::ViewItemUse(ref vp) => {

src/test/auxiliary/crateresolve4b-1.rs

@@ -13,6 +13,6 @@
 #![crate_id="crateresolve4b#0.1"]
 #![crate_type = "lib"]
 
-extern crate crateresolve4a = "crateresolve4a#0.2";
+extern crate "crateresolve4a#0.2" as crateresolve4a;
 
 pub fn f() -> int { crateresolve4a::g() }

src/test/auxiliary/crateresolve4b-2.rs

@@ -13,6 +13,6 @@
 #![crate_id="crateresolve4b#0.2"]
 #![crate_type = "lib"]
 
-extern crate crateresolve4a = "crateresolve4a#0.1";
+extern crate "crateresolve4a#0.1" as crateresolve4a;
 
 pub fn g() -> int { crateresolve4a::f() }

src/test/auxiliary/issue-12133-dylib2.rs

@@ -12,6 +12,6 @@
 
 #![crate_type = "dylib"]
 
-extern crate a = "issue-12133-rlib";
-extern crate b = "issue-12133-dylib";
+extern crate "issue-12133-rlib" as a;
+extern crate "issue-12133-dylib" as b;
 

src/test/auxiliary/issue-13560-3.rs

@@ -13,6 +13,6 @@
 #![crate_type = "rlib"]
 #![feature(phase)]
 
-#[phase(plugin)] extern crate t1 = "issue-13560-1";
-#[phase(plugin, link)] extern crate t2 = "issue-13560-2";
+#[phase(plugin)] extern crate "issue-13560-1" as t1;
+#[phase(plugin, link)] extern crate "issue-13560-2" as t2;
 

src/test/auxiliary/issue-13620-2.rs

@@ -8,6 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate crate1 = "issue-13620-1";
+extern crate "issue-13620-1" as crate1;
 
 pub static FOO2: crate1::Foo = crate1::FOO;

src/test/auxiliary/issue-13872-2.rs

@@ -8,6 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate foo = "issue-13872-1";
+extern crate "issue-13872-1" as foo;
 
 pub use foo::B;

src/test/auxiliary/issue-13872-3.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate bar = "issue-13872-2";
+extern crate "issue-13872-2" as bar;
 
 use bar::B;