Parsing binding patterns.

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 120 matching lines @@
   }
   bool allow_harmony_sloppy() const { return allow_harmony_sloppy_; }
   bool allow_harmony_unicode() const { return scanner()->HarmonyUnicode(); }
   bool allow_harmony_computed_property_names() const {
     return allow_harmony_computed_property_names_;
   }
   bool allow_harmony_rest_params() const {
     return allow_harmony_rest_params_;
   }
   bool allow_harmony_spreadcalls() const { return allow_harmony_spreadcalls_; }
+  bool allow_harmony_destructuring() const {
+    return allow_harmony_destructuring_;
+  }
 
   bool allow_strong_mode() const { return allow_strong_mode_; }
 
   // Setters that determine whether certain syntactical constructs are
   // allowed to be parsed by this instance of the parser.
   void set_allow_lazy(bool allow) { allow_lazy_ = allow; }
   void set_allow_natives(bool allow) { allow_natives_ = allow; }
   void set_allow_harmony_arrow_functions(bool allow) {
     allow_harmony_arrow_functions_ = allow;
   }
@@ skipping 15 matching lines @@
   void set_allow_harmony_computed_property_names(bool allow) {
     allow_harmony_computed_property_names_ = allow;
   }
   void set_allow_harmony_rest_params(bool allow) {
     allow_harmony_rest_params_ = allow;
   }
   void set_allow_harmony_spreadcalls(bool allow) {
     allow_harmony_spreadcalls_ = allow;
   }
   void set_allow_strong_mode(bool allow) { allow_strong_mode_ = allow; }
+  void set_allow_harmony_destructuring(bool allow) {
+    allow_harmony_destructuring_ = allow;
+  }
+
 
  protected:
   enum AllowRestrictedIdentifiers {
     kAllowRestrictedIdentifiers,
     kDontAllowRestrictedIdentifiers
   };
 
   enum Mode {
     PARSE_LAZILY,
     PARSE_EAGERLY
@@ skipping 486 matching lines @@
   }
 
   void ValidateAssignmentPattern(const ExpressionClassifier* classifier,
                                  bool* ok) {
     if (!classifier->is_valid_assignment_pattern()) {
       ReportClassifierError(classifier->assignment_pattern_error());
       *ok = false;
     }
   }
 
+  void BindingPatternUnexpectedToken(ExpressionClassifier* classifier) {

[rossberg, 2015/04/27 17:20:24]

Nit: is this function worth it, especially since it only applies in some of the
cases?

[arv (Not doing code reviews), 2015/04/27 17:56:55]

I think it is worth it. The code gets much more readable with it.

[Dmitry Lomov (no reviews), 2015/04/28 10:15:49]

+1 to arv.
Added more usages.

+    classifier->RecordBindingPatternError(
+        scanner()->location(), "unexpected_token", Token::String(peek()));
+  }
 
   // Recursive descent functions:
 
   // Parses an identifier that is valid for the current scope, in particular it
   // fails on strict mode future reserved keywords in a strict scope. If
   // allow_eval_or_arguments is kAllowEvalOrArguments, we allow "eval" or
   // "arguments" as identifier even in strict mode (this is needed in cases like
   // "var foo = eval;").
   IdentifierT ParseIdentifier(AllowRestrictedIdentifiers, bool* ok);
   IdentifierT ParseAndClassifyIdentifier(ExpressionClassifier* classifier,
@@ skipping 158 matching lines @@
   bool stack_overflow_;
 
   bool allow_lazy_;
   bool allow_natives_;
   bool allow_harmony_arrow_functions_;
   bool allow_harmony_object_literals_;
   bool allow_harmony_sloppy_;
   bool allow_harmony_computed_property_names_;
   bool allow_harmony_rest_params_;
   bool allow_harmony_spreadcalls_;
+  bool allow_harmony_destructuring_;
   bool allow_strong_mode_;
 };
 
 
 class PreParserIdentifier {
  public:
   PreParserIdentifier() : type_(kUnknownIdentifier) {}
   static PreParserIdentifier Default() {
     return PreParserIdentifier(kUnknownIdentifier);
   }
@@ skipping 1315 matching lines @@
   //   ClassLiteral
   //   '(' Expression ')'
   //   TemplateLiteral
 
   int beg_pos = scanner()->peek_location().beg_pos;
   int end_pos = scanner()->peek_location().end_pos;
   ExpressionT result = this->EmptyExpression();
   Token::Value token = peek();
   switch (token) {
     case Token::THIS: {
+      BindingPatternUnexpectedToken(classifier);
       Consume(Token::THIS);
       if (is_strong(language_mode())) {
         // Constructors' usages of 'this' in strong mode are parsed separately.
         // TODO(rossberg): this does not work with arrow functions yet.
         if (i::IsConstructor(function_state_->kind())) {
           ReportMessage("strong_constructor_this");
           *ok = false;
           break;
         }
       }
       scope_->RecordThisUsage();
       result = this->ThisExpression(scope_, factory(), beg_pos);
       break;
     }
 
     case Token::NULL_LITERAL:
     case Token::TRUE_LITERAL:
     case Token::FALSE_LITERAL:
-    case Token::SMI:
-    case Token::NUMBER:
+      BindingPatternUnexpectedToken(classifier);
       Next();
       result =
           this->ExpressionFromLiteral(token, beg_pos, scanner(), factory());
+      break;
+    case Token::SMI:
+    case Token::NUMBER:
+      classifier->RecordBindingPatternError(scanner()->location(),
+                                            "unexpected_token_number");
+      Next();
+      result =
+          this->ExpressionFromLiteral(token, beg_pos, scanner(), factory());
       break;
 
     case Token::IDENTIFIER:
     case Token::LET:
     case Token::STATIC:
     case Token::YIELD:
     case Token::FUTURE_STRICT_RESERVED_WORD: {
       // Using eval or arguments in this context is OK even in strict mode.
       IdentifierT name = ParseAndClassifyIdentifier(classifier, CHECK_OK);
       result = this->ExpressionFromIdentifier(name, beg_pos, end_pos, scope_,
                                               factory());
       break;
     }
 
     case Token::STRING: {
+      classifier->RecordBindingPatternError(scanner()->location(),
+                                            "unexpected_token_string");
       Consume(Token::STRING);
       result = this->ExpressionFromString(beg_pos, scanner(), factory());
       break;
     }
 
     case Token::ASSIGN_DIV:
       result = this->ParseRegExpLiteral(true, classifier, CHECK_OK);
       break;
 
     case Token::DIV:
@@ skipping 26 matching lines @@
         // Heuristically try to detect immediately called functions before
         // seeing the call parentheses.
         parenthesized_function_ = (peek() == Token::FUNCTION);
         result = this->ParseExpression(true, classifier, CHECK_OK);
         result->increase_parenthesization_level();
         Expect(Token::RPAREN, CHECK_OK);
       }
       break;
 
     case Token::CLASS: {
+      BindingPatternUnexpectedToken(classifier);
       Consume(Token::CLASS);
       if (!allow_harmony_sloppy() && is_sloppy(language_mode())) {
         ReportMessage("sloppy_lexical");
         *ok = false;
         break;
       }
       int class_token_position = position();
       IdentifierT name = this->EmptyIdentifier();
       bool is_strict_reserved_name = false;
       Scanner::Location class_name_location = Scanner::Location::invalid();
@@ skipping 644 matching lines @@
   //   'typeof' UnaryExpression
   //   '++' UnaryExpression
   //   '--' UnaryExpression
   //   '+' UnaryExpression
   //   '-' UnaryExpression
   //   '~' UnaryExpression
   //   '!' UnaryExpression
 
   Token::Value op = peek();
   if (Token::IsUnaryOp(op)) {
+    classifier->RecordBindingPatternError(
+        scanner()->location(), "unexpected_token", Token::String(op));
+    classifier->RecordAssignmentPatternError(
+        scanner()->location(), "unexpected_token", Token::String(op));
     op = Next();
     int pos = position();
     ExpressionT expression = ParseUnaryExpression(classifier, CHECK_OK);
 
     if (op == Token::DELETE && is_strict(language_mode())) {
       if (is_strong(language_mode())) {
         ReportMessage("strong_delete");
         *ok = false;
         return this->EmptyExpression();
       } else if (this->IsIdentifier(expression)) {
         // "delete identifier" is a syntax error in strict mode.
         ReportMessage("strict_delete");
         *ok = false;
         return this->EmptyExpression();
       }
     }
 
     // Allow Traits do rewrite the expression.
     return this->BuildUnaryExpression(expression, op, pos, factory());
   } else if (Token::IsCountOp(op)) {
+    classifier->RecordBindingPatternError(
+        scanner()->location(), "unexpected_token", Token::String(op));
+    classifier->RecordAssignmentPatternError(
+        scanner()->location(), "unexpected_token", Token::String(op));
     op = Next();
     Scanner::Location lhs_location = scanner()->peek_location();
     ExpressionT expression = this->ParseUnaryExpression(classifier, CHECK_OK);
     expression = this->CheckAndRewriteReferenceExpression(
         expression, lhs_location, "invalid_lhs_in_prefix_op", CHECK_OK);
     this->MarkExpressionAsAssigned(expression);
 
     return factory()->NewCountOperation(op,
                                         true /* prefix */,
                                         expression,
@@ skipping 10 matching lines @@
 ParserBase<Traits>::ParsePostfixExpression(ExpressionClassifier* classifier,
                                            bool* ok) {
   // PostfixExpression ::
   //   LeftHandSideExpression ('++' | '--')?
 
   Scanner::Location lhs_location = scanner()->peek_location();
   ExpressionT expression =
       this->ParseLeftHandSideExpression(classifier, CHECK_OK);
   if (!scanner()->HasAnyLineTerminatorBeforeNext() &&
       Token::IsCountOp(peek())) {
+    classifier->RecordBindingPatternError(

[arv (Not doing code reviews), 2015/04/27 17:56:55]

Maybe introduce a RecordPatternError that does both?

[Dmitry Lomov (no reviews), 2015/04/28 10:15:49]

On second thoughts, I removed all RecordAssignmentPatternErrors for now, since I
do not have tests for them and they are likely incorrect.

+        scanner()->location(), "unexpected_token", Token::String(peek()));
+    classifier->RecordAssignmentPatternError(
+        scanner()->location(), "unexpected_token", Token::String(peek()));
+
     expression = this->CheckAndRewriteReferenceExpression(
         expression, lhs_location, "invalid_lhs_in_postfix_op", CHECK_OK);
     expression = this->MarkExpressionAsAssigned(expression);
 
     Token::Value next = Next();
     expression =
         factory()->NewCountOperation(next,
                                      false /* postfix */,
                                      expression,
                                      position());
   }
   return expression;
 }
 
 
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
 ParserBase<Traits>::ParseLeftHandSideExpression(
     ExpressionClassifier* classifier, bool* ok) {
   // LeftHandSideExpression ::
   //   (NewExpression | MemberExpression) ...
 
   ExpressionT result =
       this->ParseMemberWithNewPrefixesExpression(classifier, CHECK_OK);
 
   while (true) {
     switch (peek()) {
       case Token::LBRACK: {
+        BindingPatternUnexpectedToken(classifier);
         Consume(Token::LBRACK);
         int pos = position();
         ExpressionT index = ParseExpression(true, classifier, CHECK_OK);
         result = factory()->NewProperty(result, index, pos);
         Expect(Token::RBRACK, CHECK_OK);
         break;
       }
 
       case Token::LPAREN: {
+        BindingPatternUnexpectedToken(classifier);
+
         if (is_strong(language_mode()) && this->IsIdentifier(result) &&
             this->IsEval(this->AsIdentifier(result))) {
           ReportMessage("strong_direct_eval");
           *ok = false;
           return this->EmptyExpression();
         }
         int pos;
         if (scanner()->current_token() == Token::IDENTIFIER) {
           // For call of an identifier we want to report position of
           // the identifier as position of the call in the stack trace.
@@ skipping 29 matching lines @@
           args = Traits::PrepareSpreadArguments(args);
           result = Traits::SpreadCall(result, args, pos);
         } else {
           result = factory()->NewCall(result, args, pos);
         }
         if (fni_ != NULL) fni_->RemoveLastFunction();
         break;
       }
 
       case Token::PERIOD: {
+        BindingPatternUnexpectedToken(classifier);
         Consume(Token::PERIOD);
         int pos = position();
         IdentifierT name = ParseIdentifierName(CHECK_OK);
         result = factory()->NewProperty(
             result, factory()->NewStringLiteral(name, pos), pos);
         if (fni_ != NULL) this->PushLiteralName(fni_, name);
         break;
       }
 
       default:
@@ skipping 18 matching lines @@
 
   // Examples of new expression:
   // new foo.bar().baz means (new (foo.bar)()).baz
   // new foo()() means (new foo())()
   // new new foo()() means (new (new foo())())
   // new new foo means new (new foo)
   // new new foo() means new (new foo())
   // new new foo().bar().baz means (new (new foo()).bar()).baz
 
   if (peek() == Token::NEW) {
+    BindingPatternUnexpectedToken(classifier);
     Consume(Token::NEW);
     int new_pos = position();
     ExpressionT result = this->EmptyExpression();
     if (peek() == Token::SUPER) {
       const bool is_new = true;
       result = ParseSuperExpression(is_new, classifier, CHECK_OK);
     } else {
       result = this->ParseMemberWithNewPrefixesExpression(classifier, CHECK_OK);
     }
     if (peek() == Token::LPAREN) {
@@ skipping 30 matching lines @@
   //   (PrimaryExpression | FunctionLiteral | ClassLiteral)
   //     ('[' Expression ']' | '.' Identifier | Arguments | TemplateLiteral)*
 
   // The '[' Expression ']' and '.' Identifier parts are parsed by
   // ParseMemberExpressionContinuation, and the Arguments part is parsed by the
   // caller.
 
   // Parse the initial primary or function expression.
   ExpressionT result = this->EmptyExpression();
   if (peek() == Token::FUNCTION) {
+    BindingPatternUnexpectedToken(classifier);
+
     Consume(Token::FUNCTION);
     int function_token_position = position();
     bool is_generator = Check(Token::MUL);
     IdentifierT name = this->EmptyIdentifier();
     bool is_strict_reserved_name = false;
     Scanner::Location function_name_location = Scanner::Location::invalid();
     FunctionLiteral::FunctionType function_type =
         FunctionLiteral::ANONYMOUS_EXPRESSION;
     if (peek_any_identifier()) {
       name = ParseIdentifierOrStrictReservedWord(&is_strict_reserved_name,
@@ skipping 100 matching lines @@
   return factory()->NewAssignment(Token::ASSIGN, left, right, pos);
 }
 
 
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
 ParserBase<Traits>::ParseStrongSuperCallExpression(
     ExpressionClassifier* classifier, bool* ok) {
   // SuperCallExpression ::  (strong mode)
   //  'super' '(' ExpressionList ')'
+  BindingPatternUnexpectedToken(classifier);
 
   Consume(Token::SUPER);
   int pos = position();
   Scanner::Location super_loc = scanner()->location();
   ExpressionT expr = this->SuperReference(scope_, factory());
 
   if (peek() != Token::LPAREN) {
     ReportMessage("strong_constructor_super");
     *ok = false;
     return this->EmptyExpression();
@@ skipping 76 matching lines @@
 
 template <class Traits>
 typename ParserBase<Traits>::ExpressionT
 ParserBase<Traits>::ParseMemberExpressionContinuation(
     ExpressionT expression, ExpressionClassifier* classifier, bool* ok) {
   // Parses this part of MemberExpression:
   // ('[' Expression ']' | '.' Identifier | TemplateLiteral)*
   while (true) {
     switch (peek()) {
       case Token::LBRACK: {
+        BindingPatternUnexpectedToken(classifier);
+
         Consume(Token::LBRACK);
         int pos = position();
         ExpressionT index = this->ParseExpression(true, classifier, CHECK_OK);
         expression = factory()->NewProperty(expression, index, pos);
         if (fni_ != NULL) {
           this->PushPropertyName(fni_, index);
         }
         Expect(Token::RBRACK, CHECK_OK);
         break;
       }
       case Token::PERIOD: {
+        BindingPatternUnexpectedToken(classifier);
+
         Consume(Token::PERIOD);
         int pos = position();
         IdentifierT name = ParseIdentifierName(CHECK_OK);
         expression = factory()->NewProperty(
             expression, factory()->NewStringLiteral(name, pos), pos);
         if (fni_ != NULL) {
           this->PushLiteralName(fni_, name);
         }
         break;
       }
       case Token::TEMPLATE_SPAN:
       case Token::TEMPLATE_TAIL: {
+        BindingPatternUnexpectedToken(classifier);
         int pos;
         if (scanner()->current_token() == Token::IDENTIFIER) {
           pos = position();
         } else {
           pos = peek_position();
           if (expression->IsFunctionLiteral() && mode() == PARSE_EAGERLY) {
             // If the tag function looks like an IIFE, set_parenthesized() to
             // force eager compilation.
             expression->AsFunctionLiteral()->set_should_eager_compile();
           }
@@ skipping 126 matching lines @@
   int materialized_literal_count = -1;
   int expected_property_count = -1;
   int handler_count = 0;
   Scanner::Location super_loc;
 
   {
     typename Traits::Type::Factory function_factory(ast_value_factory());
     FunctionState function_state(&function_state_, &scope_, scope,
                                  kArrowFunction, &function_factory);
 
+    if (peek() == Token::ARROW) {
+      BindingPatternUnexpectedToken(classifier);
+    }
     Expect(Token::ARROW, CHECK_OK);
 
     if (peek() == Token::LBRACE) {
       // Multiple statement body
       Consume(Token::LBRACE);
       bool is_lazily_parsed =
           (mode() == PARSE_LAZILY && scope_->AllowsLazyCompilation());
       if (is_lazily_parsed) {
         body = this->NewStatementList(0, zone());
         this->SkipLazyFunctionBody(&materialized_literal_count,
@@ skipping 237 matching lines @@
       *ok = false;
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H