[es6] implement destructuring assignment [clean diff]

src/parser.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/parser.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/ast-literal-reindexer.h"
 #include "src/bailout-reason.h"
@@ skipping 3585 matching lines @@
 
   inner_scope->set_end_position(scanner()->location().end_pos);
   inner_block->set_scope(inner_scope);
   scope_ = for_scope;
 
   outer_loop->Initialize(NULL, NULL, NULL, inner_block);
   return outer_block;
 }
 
 
+Expression* Parser::DesugarDestructuringAssignmentInternal(Expression* expr,
+                                                           Variable** result) {
+  Assignment* assign = expr->AsAssignment();
+  Expression* value = assign->value();
+  Expression* target = assign->target();
+  if (value->IsAssignment()) {
+    value = DesugarDestructuringAssignmentInternal(value, result);
+  }
+  if (target->IsObjectLiteral() || target->IsArrayLiteral()) {
+    Block* block = factory()->NewBlock(nullptr, 8, false, expr->position());
+    bool ok = true;
+    *result = PatternRewriter::RewriteDestructuringAssignment(
+        this, block, target, value, *result, &ok);
+    DCHECK_EQ(ok, true);
+    DCHECK_NOT_NULL(*result);
+    return factory()->NewDoExpression(block, *result, expr->position());
+  }
+
+  return expr;
+}
+
+
 Expression* Parser::DesugarDestructuringAssignment(Expression* expr) {
-  // TODO(caitp): implement the desugaring
   DCHECK(expr->IsAssignment());
-  Assignment* assign = expr->AsAssignment();
-  while (assign->value()->IsAssignment()) {
-    assign = assign->value()->AsAssignment();
-  }
-  return assign->value();
+  Variable* result = nullptr;
+
+  return DesugarDestructuringAssignmentInternal(expr, &result);
 }
 
 
 Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
                                      bool* ok) {
   // ForStatement ::
   //   'for' '(' Expression? ';' Expression? ';' Expression? ')' Statement
 
   int stmt_pos = peek_position();
   bool is_const = false;
@@ skipping 2774 matching lines @@
 
 Expression* Parser::SpreadCallNew(Expression* function,
                                   ZoneList<v8::internal::Expression*>* args,
                                   int pos) {
   args->InsertAt(0, function, zone());
 
   return factory()->NewCallRuntime(Context::REFLECT_CONSTRUCT_INDEX, args, pos);
 }
 }  // namespace internal
 }  // namespace v8