Support move as an initializer.

Author: msullivan

src/comp/front/ast.rs

@@ -208,6 +208,7 @@ tag stmt_ {
 tag init_op {
     init_assign;
     init_recv;
+    init_move;
 }
 
 type initializer = rec(init_op op,

src/comp/front/parser.rs

@@ -1449,6 +1449,11 @@ fn parse_initializer(&parser p) -> option::t[ast::initializer] {
             ret some(rec(op = ast::init_assign,
                          expr = parse_expr(p)));
         }
+        case (token::LARROW) {
+            p.bump();
+            ret some(rec(op = ast::init_move,
+                         expr = parse_expr(p)));
+        }
         // Now that the the channel is the first argument to receive,
         // combining it with an initializer doesn't really make sense.
         // case (token::RECV) {

src/comp/middle/trans.rs

@@ -6375,6 +6375,11 @@ fn init_local(&@block_ctxt cx, &@ast::local local) -> result {
                     auto sub = trans_expr(bcx, init.expr);
                     bcx = copy_val(sub.bcx, INIT, llptr, sub.val, ty).bcx;
                 }
+                case (ast::init_move) {
+                    auto sub = trans_lval(bcx, init.expr);
+                    bcx = move_val(sub.res.bcx, INIT, llptr,
+                                   sub.res.val, ty).bcx;
+                }
                 case (ast::init_recv) {
                     bcx = recv_val(bcx, llptr, init.expr, ty, INIT).bcx;
                 }

src/comp/middle/typeck.rs

@@ -2723,6 +2723,9 @@ fn check_decl_initializer(&@stmt_ctxt scx, &ast::def_id lid,
         case (ast::init_assign) {
             pushdown::pushdown_expr(scx, lty, init.expr);
         }
+        case (ast::init_move) {
+            pushdown::pushdown_expr(scx, lty, init.expr);
+        }
         case (ast::init_recv) {
             auto port_ty = ty::mk_port(scx.fcx.ccx.tcx, lty);
             pushdown::pushdown_expr(scx, port_ty, init.expr);

src/comp/pretty/pprust.rs

@@ -865,9 +865,12 @@ fn print_decl(&ps s, &@ast::decl decl) {
                         case (ast::init_assign) {
                             word_space(s, "=");
                         }
-                        case (ast::init_recv) {
+                        case (ast::init_move) {
                             word_space(s, "<-");
                         }
+                        case (ast::init_recv) {
+                            word_space(s, "|>");
+                        }
                     }
                     print_expr(s, init.expr);
                 }