rustc: Make functional record and struct update use ".." instead of "with".

"with" is still accepted for backwards compatibility.

Author: pcwalton

src/libsyntax/parse/parser.rs

@@ -928,15 +928,16 @@ class parser {
                             !self.is_keyword(~"with") {
                         self.expect(token::COMMA);
                         if self.token == token::RBRACE ||
-                                self.is_keyword(~"with") {
+                                self.is_keyword(~"with") ||
+                                self.token == token::DOTDOT {
                             // Accept an optional trailing comma.
                             break;
                         }
                         vec::push(fields, self.parse_field(token::COLON));
                     }
 
                     let base;
-                    if self.eat_keyword(~"with") {
+                    if self.eat_keyword(~"with") || self.eat(token::DOTDOT) {
                         base = some(self.parse_expr());
                     } else {
                         base = none;
@@ -1548,6 +1549,16 @@ class parser {
         let mut fields = ~[self.parse_field(token::COLON)];
         let mut base = none;
         while self.token != token::RBRACE {
+            if self.token == token::COMMA
+                && self.look_ahead(1) == token::DOTDOT {
+                self.bump();
+                self.bump();
+                base = some(self.parse_expr()); break;
+            }
+
+            // XXX: Remove "with" after all code is converted over and there's
+            // a snapshot.
+
             // optional comma before "with"
             if self.token == token::COMMA
                 && self.token_is_keyword(~"with",

src/libsyntax/print/pprust.rs

@@ -1039,7 +1039,9 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
           some(expr) => {
             if vec::len(fields) > 0u { space(s.s); }
             ibox(s, indent_unit);
-            word_space(s, ~"with");
+            word(s.s, ~",");
+            space(s.s);
+            word(s.s, ~"..");
             print_expr(s, expr);
             end(s);
           }
@@ -1055,7 +1057,9 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
             some(expr) => {
                 if vec::len(fields) > 0u { space(s.s); }
                 ibox(s, indent_unit);
-                word_space(s, ~"with");
+                word(s.s, ~",");
+                space(s.s);
+                word(s.s, ~"..");
                 print_expr(s, expr);
                 end(s);
             }

src/test/run-pass/functional-struct-update.rs

@@ -5,8 +5,7 @@ struct Foo {
 
 fn main() {
     let a = Foo { x: 1, y: 2 };
-    let b = Foo { x: 3 with a };
-    let c = Foo { x: 4, with a };
-    io::println(fmt!("%? %?", b, c));
+    let c = Foo { x: 4, .. a };
+    io::println(fmt!("%?", c));
 }