[destructuring] Implement parameter pattern matching.

src/scopes.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/v8.h"
 
 #include "src/accessors.h"
 #include "src/bootstrapper.h"
 #include "src/messages.h"
 #include "src/parser.h"
@@ skipping 441 matching lines @@
   for (Scope* scope = this;
        scope != NULL;
        scope = scope->outer_scope()) {
     Variable* var = scope->LookupLocal(name);
     if (var != NULL) return var;
   }
   return NULL;
 }
 
 
-Variable* Scope::DeclareParameter(const AstRawString* name, VariableMode mode,
-                                  bool is_rest, bool* is_duplicate) {
+Variable* Scope::DeclareParameter(const AstRawString* name, Expression* pattern,
+                                  VariableMode mode, bool is_rest,
+                                  bool* is_duplicate) {
   DCHECK(!already_resolved());
   DCHECK(is_function_scope());
   Variable* var = variables_.Declare(this, name, mode, Variable::NORMAL,
                                      kCreatedInitialized);
   if (is_rest) {
     DCHECK_NULL(rest_parameter_);
     rest_parameter_ = var;
     rest_index_ = num_parameters();
   }
-  // TODO(wingo): Avoid O(n^2) check.
-  *is_duplicate = IsDeclaredParameter(name);
-  params_.Add(var, zone());
+
+  if (pattern == nullptr) {
+    // TODO(wingo): Avoid O(n^2) check.
+    *is_duplicate = IsDeclaredParameter(name);
+  }
+  params_.Add(Parameter(var, pattern), zone());
   return var;
 }
 
 
 Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
                               InitializationFlag init_flag, Variable::Kind kind,
                               MaybeAssignedFlag maybe_assigned_flag,
                               int declaration_group_start) {
   DCHECK(!already_resolved());
   // This function handles VAR, LET, and CONST modes.  DYNAMIC variables are
@@ skipping 405 matching lines @@
   if (!scope_name_->IsEmpty()) {
     PrintF(" ");
     PrintName(scope_name_);
   }
 
   // Print parameters, if any.
   if (is_function_scope()) {
     PrintF(" (");
     for (int i = 0; i < params_.length(); i++) {
       if (i > 0) PrintF(", ");
-      PrintName(params_[i]->raw_name());
+      PrintName(params_[i].var->raw_name());
     }
     PrintF(")");
   }
 
   PrintF(" { // (%d, %d)\n", start_position(), end_position());
 
   // Function name, if any (named function literals, only).
   if (function_ != NULL) {
     Indent(n1, "// (local) function name: ");
     PrintName(function_->proxy()->raw_name());
@@ skipping 418 matching lines @@
   if (is_script_scope() && IsLexicalVariableMode(var->mode())) return true;
   return var->has_forced_context_allocation() ||
       scope_calls_eval_ ||
       inner_scope_calls_eval_ ||
       scope_contains_with_;
 }
 
 
 bool Scope::HasArgumentsParameter(Isolate* isolate) {
   for (int i = 0; i < params_.length(); i++) {
-    if (params_[i]->name().is_identical_to(
+    if (params_[i].var->name().is_identical_to(
             isolate->factory()->arguments_string())) {
       return true;
     }
   }
   return false;
 }
 
 
 void Scope::AllocateStackSlot(Variable* var) {
   if (is_block_scope()) {
@@ skipping 40 matching lines @@
 
   if (rest_parameter_ && !MustAllocate(rest_parameter_)) {
     rest_parameter_ = NULL;
   }
 
   // The same parameter may occur multiple times in the parameters_ list.
   // If it does, and if it is not copied into the context object, it must
   // receive the highest parameter index for that parameter; thus iteration
   // order is relevant!
   for (int i = params_.length() - 1; i >= 0; --i) {
-    Variable* var = params_[i];
+    Variable* var = params_[i].var;
     if (var == rest_parameter_) continue;
 
     DCHECK(var->scope() == this);
     if (uses_sloppy_arguments || has_forced_context_allocation()) {
       // Force context allocation of the parameter.
       var->ForceContextAllocation();
     }
     AllocateParameter(var, i);
   }
 }
@@ skipping 152 matching lines @@
 }
 
 
 int Scope::ContextLocalCount() const {
   if (num_heap_slots() == 0) return 0;
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
       (function_ != NULL && function_->proxy()->var()->IsContextSlot() ? 1 : 0);
 }
 }  // namespace internal
 }  // namespace v8