Implement new syntax for ImportDeclarations

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/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
 #include "src/base/platform/platform.h"
@@ skipping 1281 matching lines @@
   Interface* interface = scope->interface();
   Module* result = factory()->NewModuleLiteral(body, interface, pos);
   interface->Freeze(ok);
   DCHECK(*ok);
   interface->Unify(scope->interface(), zone(), ok);
   DCHECK(*ok);
   return result;
 }
 
 
-void* Parser::ParseModuleDeclarationClause(ZoneList<const AstRawString*>* names,
-                                           bool* ok) {
-  // Handles both imports and exports:
+void* Parser::ParseExportClause(ZoneList<const AstRawString*>* names,
+                                Scanner::Location* reserved_loc, bool* ok) {
+  // ExportClause :
+  //   '{' '}'
+  //   '{' ExportsList '}'
+  //   '{' ExportsList ',' '}'
   //
-  // ImportOrExportClause :
-  //   '{' '}'
-  //   '{' ImportOrExportsList '}'
-  //   '{' ImportOrExportsList ',' '}'
+  // ExportsList :
+  //   ExportSpecifier
+  //   ExportsList ',' ExportSpecifier
   //
-  // ImportOrExportsList :
-  //   ImportOrExportSpecifier
-  //   ImportOrExportsList ',' ImportOrExportSpecifier
-  //
-  // ImportOrExportSpecifier :
+  // ExportSpecifier :
   //   IdentifierName
   //   IdentifierName 'as' IdentifierName
 
   Expect(Token::LBRACE, CHECK_OK);
 
-  while (peek() != Token::RBRACE) {
+  Token::Value name_tok;
+  while ((name_tok = peek()) != Token::RBRACE) {
+    // Keep track of the first reserved word encountered in case our
+    // caller needs to report an error.
+    if (!reserved_loc->IsValid() &&
+        !Token::IsIdentifier(name_tok, STRICT, false)) {
+      *reserved_loc = scanner()->location();
+    }
     const AstRawString* name = ParseIdentifierName(CHECK_OK);
     names->Add(name, zone());
     const AstRawString* export_name = NULL;
     if (CheckContextualKeyword(CStrVector("as"))) {
       export_name = ParseIdentifierName(CHECK_OK);
     }
     // TODO(ES6): Return the export_name as well as the name.
     USE(export_name);
     if (peek() == Token::RBRACE) break;
     Expect(Token::COMMA, CHECK_OK);
   }
 
   Expect(Token::RBRACE, CHECK_OK);
 
   return 0;
 }
 
 
+void* Parser::ParseNamedImports(ZoneList<const AstRawString*>* names,
+                                bool* ok) {
+  // NamedImports :
+  //   '{' '}'
+  //   '{' ImportsList '}'
+  //   '{' ImportsList ',' '}'
+  //
+  // ImportsList :
+  //   ImportSpecifier
+  //   ImportsList ',' ImportSpecifier
+  //
+  // ImportSpecifier :
+  //   BindingIdentifier
+  //   IdentifierName 'as' BindingIdentifier
+
+  Expect(Token::LBRACE, CHECK_OK);
+
+  Token::Value name_tok;
+  while ((name_tok = peek()) != Token::RBRACE) {
+    const AstRawString* name = ParseIdentifierName(CHECK_OK);
+    const AstRawString* import_name = NULL;
+    // In the presence of 'as', the left-side of the 'as' can
+    // be any IdentifierName. But without 'as', it must be a valid
+    // BindingIdentiifer.
+    if (CheckContextualKeyword(CStrVector("as"))) {
+      import_name = ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+    } else if (!Token::IsIdentifier(name_tok, STRICT, false)) {
+      *ok = false;
+      ReportMessageAt(scanner()->location(), "unexpected_reserved");
+      return NULL;
+    } else if (IsEvalOrArguments(name)) {
+      *ok = false;
+      ReportMessageAt(scanner()->location(), "strict_eval_arguments");
+      return NULL;
+    }
+    // TODO(ES6): Return the import_name as well as the name.
+    names->Add(name, zone());
+    USE(import_name);
+    if (peek() == Token::RBRACE) break;
+    Expect(Token::COMMA, CHECK_OK);
+  }
+
+  Expect(Token::RBRACE, CHECK_OK);
+
+  return NULL;
+}
+
+
 Statement* Parser::ParseImportDeclaration(bool* ok) {
-  // ImportDeclaration:
-  //    'import' IdentifierName (',' IdentifierName)* 'from' ModuleUrl ';'
+  // ImportDeclaration :
+  //   'import' ImportClause 'from' ModuleSpecifier ';'
+  //   'import' ModuleSpecifier ';'
   //
-  // TODO(ES6): implement current syntax
+  // ImportClause :
+  //   NameSpaceImport
+  //   NamedImports
+  //   ImportedDefaultBinding
+  //   ImportedDefaultBinding ',' NameSpaceImport
+  //   ImportedDefaultBinding ',' NamedImports
+  //
+  // NameSpaceImport :
+  //   '*' 'as' ImportedBinding
 
   int pos = peek_position();
   Expect(Token::IMPORT, CHECK_OK);
+
+  Token::Value tok = peek();
+
+  // 'import' ModuleSpecifier ';'
+  if (tok == Token::STRING) {
+    ParseModuleSpecifier(CHECK_OK);
+    ExpectSemicolon(CHECK_OK);
+    return factory()->NewEmptyStatement(pos);
+  }
+
+  // Parse ImportedDefaultBinding if present.
+  const AstRawString* imported_default_binding = NULL;
+  if (tok != Token::MUL && tok != Token::LBRACE) {
+    imported_default_binding =
+        ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+  }
+
+  const AstRawString* module_instance_binding = NULL;
   ZoneList<const AstRawString*> names(1, zone());
+  if (imported_default_binding == NULL || Check(Token::COMMA)) {
+    switch (peek()) {
+      case Token::MUL: {
+        Consume(Token::MUL);
+        ExpectContextualKeyword(CStrVector("as"), CHECK_OK);
+        module_instance_binding =
+            ParseIdentifier(kDontAllowEvalOrArguments, CHECK_OK);
+        break;
+      }
 
-  const AstRawString* name = ParseIdentifierName(CHECK_OK);
-  names.Add(name, zone());
-  while (peek() == Token::COMMA) {
-    Consume(Token::COMMA);
-    name = ParseIdentifierName(CHECK_OK);
-    names.Add(name, zone());
+      case Token::LBRACE:
+        ParseNamedImports(&names, CHECK_OK);
+        break;
+
+      default:
+        *ok = false;
+        ReportUnexpectedToken(scanner()->current_token());
+        return NULL;
+    }
   }
 
   ExpectContextualKeyword(CStrVector("from"), CHECK_OK);
   Module* module = ParseModuleSpecifier(CHECK_OK);
+  USE(module);
+
   ExpectSemicolon(CHECK_OK);
 
-  // TODO(ES6): Do something with ParseModuleSpecifier's return value.
-  USE(module);
+  if (module_instance_binding != NULL) {
+    // TODO(ES6): Bind name to the Module Instance Object of module.
+  }
+
+  if (imported_default_binding != NULL) {
+    // TODO(ES6): Add an appropriate declaration.
+  }
 
   for (int i = 0; i < names.length(); ++i) {
     // TODO(ES6): Add an appropriate declaration for each name
   }
 
   return factory()->NewEmptyStatement(pos);
 }
 
 
 Statement* Parser::ParseExportDefault(bool* ok) {
@@ skipping 54 matching lines @@
       Module* module = ParseModuleSpecifier(CHECK_OK);
       ExpectSemicolon(CHECK_OK);
       // TODO(ES6): Do something with the return value
       // of ParseModuleSpecifier.
       USE(module);
       is_export_from = true;
       result = factory()->NewEmptyStatement(pos);
       break;
     }
 
-    case Token::LBRACE:
-      ParseModuleDeclarationClause(&names, CHECK_OK);
+    case Token::LBRACE: {
+      // There are two cases here:
+      //
+      // 'export' ExportClause ';'
+      // and
+      // 'export' ExportClause FromClause ';'
+      //
+      // In the first case, the exported identifiers in ExportClause must
+      // not be reserved words, while in the latter they may be. We
+      // pass in a location that gets filled with the first reserved word
+      // encountered, and then throw a SyntaxError if we are in the
+      // non-FromClause case.
+      Scanner::Location reserved_loc = Scanner::Location::invalid();
+      ParseExportClause(&names, &reserved_loc, CHECK_OK);
       if (CheckContextualKeyword(CStrVector("from"))) {
         Module* module = ParseModuleSpecifier(CHECK_OK);
         // TODO(ES6): Do something with the return value
         // of ParseModuleSpecifier.
         USE(module);
         is_export_from = true;
+      } else if (reserved_loc.IsValid()) {
+        // No FromClause, so reserved words are invalid in ExportClause.
+        *ok = false;
+        ReportMessageAt(reserved_loc, "unexpected_reserved");
+        return NULL;
       }
       ExpectSemicolon(CHECK_OK);
       result = factory()->NewEmptyStatement(pos);
       break;
+    }
 
     case Token::FUNCTION:
       result = ParseFunctionDeclaration(&names, CHECK_OK);
       break;
 
     case Token::CLASS:
       result = ParseClassDeclaration(&names, CHECK_OK);
       break;
 
     case Token::VAR:
@@ skipping 3772 matching lines @@
     } else {
       const uc16* data = reinterpret_cast<const uc16*>(raw_string->raw_data());
       running_hash = StringHasher::ComputeRunningHash(running_hash, data,
                                                       raw_string->length());
     }
   }
 
   return running_hash;
 }
 } }  // namespace v8::internal