[es6] Refactor FormalParameter

src/preparser.h

 // 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.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/v8.h"
 
 #include "src/bailout-reason.h"
@@ skipping 85 matching lines @@
         stack_limit_(stack_limit),
         zone_(zone),
         scanner_(scanner),
         stack_overflow_(false),
         allow_lazy_(false),
         allow_natives_(false),
         allow_harmony_arrow_functions_(false),
         allow_harmony_sloppy_(false),
         allow_harmony_sloppy_let_(false),
         allow_harmony_computed_property_names_(false),
-        allow_harmony_rest_params_(false),
+        allow_harmony_rest_parameters_(false),
         allow_harmony_spreadcalls_(false),
         allow_harmony_destructuring_(false),
         allow_harmony_spread_arrays_(false),
         allow_harmony_new_target_(false),
         allow_strong_mode_(false),
         allow_legacy_const_(true) {}
 
 #define ALLOW_ACCESSORS(name)                           \
   bool allow_##name() const { return allow_##name##_; } \
   void set_allow_##name(bool allow) { allow_##name##_ = allow; }
 
   ALLOW_ACCESSORS(lazy);
   ALLOW_ACCESSORS(natives);
   ALLOW_ACCESSORS(harmony_arrow_functions);
   ALLOW_ACCESSORS(harmony_sloppy);
   ALLOW_ACCESSORS(harmony_sloppy_let);
   ALLOW_ACCESSORS(harmony_computed_property_names);
-  ALLOW_ACCESSORS(harmony_rest_params);
+  ALLOW_ACCESSORS(harmony_rest_parameters);
   ALLOW_ACCESSORS(harmony_spreadcalls);
   ALLOW_ACCESSORS(harmony_destructuring);
   ALLOW_ACCESSORS(harmony_spread_arrays);
   ALLOW_ACCESSORS(harmony_new_target);
   ALLOW_ACCESSORS(strong_mode);
   ALLOW_ACCESSORS(legacy_const);
 #undef ALLOW_ACCESSORS
 
   bool allow_harmony_modules() const { return scanner()->HarmonyModules(); }
   bool allow_harmony_unicode() const { return scanner()->HarmonyUnicode(); }
@@ skipping 560 matching lines @@
                                    ExpressionClassifier* classifier, bool* ok);
   ExpressionT ParseNewTargetExpression(bool* ok);
   ExpressionT ParseStrongInitializationExpression(
       ExpressionClassifier* classifier, bool* ok);
   ExpressionT ParseStrongSuperCallExpression(ExpressionClassifier* classifier,
                                              bool* ok);
 
   void ParseFormalParameter(bool is_rest,
                             FormalParametersT* parameters,
                             ExpressionClassifier* classifier, bool* ok);
-  int ParseFormalParameterList(FormalParametersT* parameters,
-                               ExpressionClassifier* classifier, bool* ok);
+  void ParseFormalParameterList(FormalParametersT* parameters,
+                                ExpressionClassifier* classifier, bool* ok);
   void CheckArityRestrictions(
       int param_count, FunctionLiteral::ArityRestriction arity_restriction,
       bool has_rest, int formals_start_pos, int formals_end_pos, bool* ok);
 
   // Checks if the expression is a valid reference expression (e.g., on the
   // left-hand side of assignments). Although ruled out by ECMA as early errors,
   // we allow calls for web compatibility and rewrite them to a runtime throw.
   ExpressionT CheckAndRewriteReferenceExpression(
       ExpressionT expression, Scanner::Location location,
       MessageTemplate::Template message, bool* ok);
@@ skipping 77 matching lines @@
 
   Scanner* scanner_;
   bool stack_overflow_;
 
   bool allow_lazy_;
   bool allow_natives_;
   bool allow_harmony_arrow_functions_;
   bool allow_harmony_sloppy_;
   bool allow_harmony_sloppy_let_;
   bool allow_harmony_computed_property_names_;
-  bool allow_harmony_rest_params_;
+  bool allow_harmony_rest_parameters_;
   bool allow_harmony_spreadcalls_;
   bool allow_harmony_destructuring_;
   bool allow_harmony_spread_arrays_;
   bool allow_harmony_new_target_;
   bool allow_strong_mode_;
   bool allow_legacy_const_;
 };
 
 
 class PreParserIdentifier {
@@ skipping 493 matching lines @@
   int* ast_properties() {
     static int dummy = 42;
     return &dummy;
   }
 };
 
 
 struct PreParserFormalParameters {
   explicit PreParserFormalParameters(Scope* scope)
       : scope(scope),
+        arity(0),
         has_rest(false),
         is_simple(true),
         materialized_literals_count(0) {}
   Scope* scope;
+  int arity;
   bool has_rest;
   bool is_simple;
   int materialized_literals_count;
 };
 
 
 class PreParser;
 
 class PreParserTraits {
  public:
@@ skipping 936 matching lines @@
           return this->EmptyExpression();
         }
         Scope* scope =
             this->NewScope(scope_, ARROW_SCOPE, FunctionKind::kArrowFunction);
         FormalParametersT parameters(scope);
         scope->set_start_position(beg_pos);
         ExpressionClassifier args_classifier;
         result = this->ParseArrowFunctionLiteral(parameters, args_classifier,
                                                  CHECK_OK);
       } else if (allow_harmony_arrow_functions() &&
-                 allow_harmony_rest_params() && Check(Token::ELLIPSIS)) {
+                 allow_harmony_rest_parameters() && Check(Token::ELLIPSIS)) {
         // (...x) => y
         Scope* scope =
             this->NewScope(scope_, ARROW_SCOPE, FunctionKind::kArrowFunction);
         FormalParametersT parameters(scope);
         scope->set_start_position(beg_pos);
         ExpressionClassifier args_classifier;
         const bool is_rest = true;
         this->ParseFormalParameter(is_rest, &parameters, &args_classifier,
                                    CHECK_OK);
         if (peek() == Token::COMMA) {
@@ skipping 91 matching lines @@
   bool seen_rest = false;
   while (peek() == Token::COMMA) {
     if (seen_rest) {
       // At this point the production can't possibly be valid, but we don't know
       // which error to signal.
       classifier->RecordArrowFormalParametersError(
           scanner()->peek_location(), MessageTemplate::kParamAfterRest);
     }
     Consume(Token::COMMA);
     bool is_rest = false;
-    if (allow_harmony_rest_params() && peek() == Token::ELLIPSIS) {
+    if (allow_harmony_rest_parameters() && peek() == Token::ELLIPSIS) {
       // 'x, y, ...z' in CoverParenthesizedExpressionAndArrowParameterList only
       // as the formal parameters of'(x, y, ...z) => foo', and is not itself a
       // valid expression or binding pattern.
       ExpressionUnexpectedToken(classifier);
       BindingPatternUnexpectedToken(classifier);
       Consume(Token::ELLIPSIS);
       seen_rest = is_rest = true;
     }
     int pos = position();
     ExpressionT right = this->ParseAssignmentExpression(
@@ skipping 1238 matching lines @@
 
   if (parameters->is_simple) {
     parameters->is_simple = !is_rest && Traits::IsIdentifier(pattern);
   }
   parameters->has_rest = is_rest;
   if (is_rest && !Traits::IsIdentifier(pattern)) {
     ReportUnexpectedToken(next);
     *ok = false;
     return;
   }
+  ++parameters->arity;
   Traits::DeclareFormalParameter(parameters, pattern, is_rest, classifier);
 }
 
 
 template <class Traits>
-int ParserBase<Traits>::ParseFormalParameterList(
+void ParserBase<Traits>::ParseFormalParameterList(
     FormalParametersT* parameters, ExpressionClassifier* classifier, bool* ok) {
   // FormalParameters[Yield,GeneratorParameter] :
   //   [empty]
   //   FormalParameterList[?Yield, ?GeneratorParameter]
   //
   // FormalParameterList[Yield,GeneratorParameter] :
   //   FunctionRestParameter[?Yield]
   //   FormalsList[?Yield, ?GeneratorParameter]
   //   FormalsList[?Yield, ?GeneratorParameter] , FunctionRestParameter[?Yield]
   //
   // FormalsList[Yield,GeneratorParameter] :
   //   FormalParameter[?Yield, ?GeneratorParameter]
   //   FormalsList[?Yield, ?GeneratorParameter] ,
   //     FormalParameter[?Yield,?GeneratorParameter]
 
-  int arity = 0;
+  DCHECK(parameters->arity == 0);

[adamk, 2015/08/03 18:20:23]

DCHECK_EQ

[rossberg, 2015/08/04 13:44:22]

Done.

 
   if (peek() != Token::RPAREN) {
     do {
-      if (++arity > Code::kMaxArguments) {
+      if (parameters->arity > Code::kMaxArguments) {
         ReportMessage(MessageTemplate::kTooManyParameters);
         *ok = false;
-        return -1;
+        return;
       }
-      bool is_rest = allow_harmony_rest_params() && Check(Token::ELLIPSIS);
+      bool is_rest = allow_harmony_rest_parameters() && Check(Token::ELLIPSIS);
       ParseFormalParameter(is_rest, parameters, classifier, ok);
-      if (!*ok) return -1;
+      if (!*ok) return;
     } while (!parameters->has_rest && Check(Token::COMMA));
 
     if (parameters->has_rest && peek() == Token::COMMA) {
       ReportMessageAt(scanner()->peek_location(),
                       MessageTemplate::kParamAfterRest);
       *ok = false;
-      return -1;
     }
   }
-
-  return arity;
 }
 
 
 template <class Traits>
 void ParserBase<Traits>::CheckArityRestrictions(
     int param_count, FunctionLiteral::ArityRestriction arity_restriction,
     bool has_rest, int formals_start_pos, int formals_end_pos, bool* ok) {
   switch (arity_restriction) {
     case FunctionLiteral::GETTER_ARITY:
       if (param_count != 0) {
@@ skipping 310 matching lines @@
       *ok = false;
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H