Add optional types to function/method declarations

src/parsing/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/parsing/parser.h"
 
 #include "src/api.h"
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-rewriter.h"
 #include "src/ast/ast-expression-visitor.h"
@@ skipping 732 matching lines @@
 
 Expression* ParserTraits::ParseV8Intrinsic(bool* ok) {
   return parser_->ParseV8Intrinsic(ok);
 }
 
 
 FunctionLiteral* ParserTraits::ParseFunctionLiteral(
     const AstRawString* name, Scanner::Location function_name_location,
     FunctionNameValidity function_name_validity, FunctionKind kind,
     int function_token_position, FunctionLiteral::FunctionType type,
-    LanguageMode language_mode, bool* ok) {
+    LanguageMode language_mode, typesystem::TypeFlags type_flags, bool* ok) {
   return parser_->ParseFunctionLiteral(
       name, function_name_location, function_name_validity, kind,
-      function_token_position, type, language_mode, ok);
+      function_token_position, type, language_mode, type_flags, ok);
 }
 
 
 ClassLiteral* ParserTraits::ParseClassLiteral(
     const AstRawString* name, Scanner::Location class_name_location,
     bool name_is_strict_reserved, int pos, bool* ok) {
   return parser_->ParseClassLiteral(name, class_name_location,
                                     name_is_strict_reserved, pos, ok);
 }
 
@@ skipping 361 matching lines @@
             ok = false;
           }
         }
       }
     } else if (shared_info->is_default_constructor()) {
       result = DefaultConstructor(
           raw_name, IsSubclassConstructor(shared_info->kind()), scope,
           shared_info->start_position(), shared_info->end_position(),
           shared_info->language_mode());
     } else {
-      result = ParseFunctionLiteral(raw_name, Scanner::Location::invalid(),
-                                    kSkipFunctionNameCheck, shared_info->kind(),
-                                    RelocInfo::kNoPosition, function_type,
-                                    shared_info->language_mode(), &ok);
+      result = ParseFunctionLiteral(
+          raw_name, Scanner::Location::invalid(), kSkipFunctionNameCheck,
+          shared_info->kind(), RelocInfo::kNoPosition, function_type,
+          shared_info->language_mode(), typesystem::kNormalTypes, &ok);
     }
     // Make sure the results agree.
     DCHECK(ok == (result != NULL));
   }
 
   // Make sure the target stack is empty.
   DCHECK(target_stack_ == NULL);
 
   if (result != NULL) {
     Handle<String> inferred_name(shared_info->inferred_name());
@@ skipping 446 matching lines @@
 
   const AstRawString* default_string = ast_value_factory()->default_string();
   ZoneList<const AstRawString*> names(1, zone());
   Statement* result = nullptr;
   Expression* default_export = nullptr;
   switch (peek()) {
     case Token::FUNCTION: {
       Consume(Token::FUNCTION);
       int pos = position();
       bool is_generator = Check(Token::MUL);
-      if (peek() == Token::LPAREN) {
+      if (peek() == Token::LPAREN || (scope_->typed() && Check(Token::LT))) {
         // FunctionDeclaration[+Default] ::
         //   'function' '(' FormalParameters ')' '{' FunctionBody '}'
         //
         // GeneratorDeclaration[+Default] ::
         //   'function' '*' '(' FormalParameters ')' '{' FunctionBody '}'
         default_export = ParseFunctionLiteral(
             default_string, Scanner::Location::invalid(),
             kSkipFunctionNameCheck,
             is_generator ? FunctionKind::kGeneratorFunction
                          : FunctionKind::kNormalFunction,
-            pos, FunctionLiteral::kDeclaration, language_mode(), CHECK_OK);
+            pos, FunctionLiteral::kDeclaration, language_mode(),
+            typesystem::kAllowSignature, CHECK_OK);
         result = factory()->NewEmptyStatement(RelocInfo::kNoPosition);
       } else {
         result = ParseFunctionDeclaration(pos, is_generator, &names, CHECK_OK);
       }
       break;
     }
 
     case Token::CLASS:
       Consume(Token::CLASS);
       if (peek() == Token::EXTENDS || peek() == Token::LBRACE) {
@@ skipping 530 matching lines @@
   // GeneratorDeclaration ::
   //   'function' '*' Identifier '(' FormalParameters ')' '{' FunctionBody '}'
   //
   // 'function' and '*' (if present) have been consumed by the caller.
   bool is_strict_reserved = false;
   const AstRawString* name = ParseIdentifierOrStrictReservedWord(
       &is_strict_reserved, CHECK_OK);
 
   FuncNameInferrer::State fni_state(fni_);
   if (fni_ != NULL) fni_->PushEnclosingName(name);
-  FunctionLiteral* fun = ParseFunctionLiteral(
-      name, scanner()->location(),
-      is_strict_reserved ? kFunctionNameIsStrictReserved
-                         : kFunctionNameValidityUnknown,
-      is_generator ? FunctionKind::kGeneratorFunction
-                   : FunctionKind::kNormalFunction,
-      pos, FunctionLiteral::kDeclaration, language_mode(), CHECK_OK);
+  FunctionLiteral* fun =
+      ParseFunctionLiteral(name, scanner()->location(),
+                           is_strict_reserved ? kFunctionNameIsStrictReserved
+                                              : kFunctionNameValidityUnknown,
+                           is_generator ? FunctionKind::kGeneratorFunction
+                                        : FunctionKind::kNormalFunction,
+                           pos, FunctionLiteral::kDeclaration, language_mode(),
+                           typesystem::kAllowSignature, CHECK_OK);
+  // Return no function declaration if just the signature was given.
+  EmptyStatement* empty = factory()->NewEmptyStatement(RelocInfo::kNoPosition);
+  if (fun == nullptr) return empty;
 
   // Even if we're not at the top-level of the global or a function
   // scope, we treat it as such and introduce the function with its
   // initial value upon entering the corresponding scope.
   // In ES6, a function behaves as a lexical binding, except in
   // a script scope, or the initial scope of eval or another function.
   VariableMode mode =
       (is_strict(language_mode()) || allow_harmony_sloppy_function()) &&
       !scope_->is_declaration_scope()
           ? LET
           : VAR;
   VariableProxy* proxy = NewUnresolved(name, mode);
   Declaration* declaration =
       factory()->NewFunctionDeclaration(proxy, mode, fun, scope_, pos);
   Declare(declaration, DeclarationDescriptor::NORMAL, true, CHECK_OK);
   if (names) names->Add(name, zone());
-  EmptyStatement* empty = factory()->NewEmptyStatement(RelocInfo::kNoPosition);
   if (is_sloppy(language_mode()) && allow_harmony_sloppy_function() &&
       !scope_->is_declaration_scope()) {
     SloppyBlockFunctionStatement* delegate =
         factory()->NewSloppyBlockFunctionStatement(empty, scope_);
     scope_->DeclarationScope()->sloppy_block_function_map()->Declare(name,
                                                                      delegate);
     return delegate;
   }
   return empty;
 }
@@ skipping 186 matching lines @@
     int decl_pos = peek_position();
     {
       ExpressionClassifier pattern_classifier(this);
       pattern = ParsePrimaryExpression(&pattern_classifier, CHECK_OK);
       ValidateBindingPattern(&pattern_classifier, CHECK_OK);
       if (IsLexicalVariableMode(parsing_result->descriptor.mode)) {
         ValidateLetPattern(&pattern_classifier, CHECK_OK);
       }
     }
 
-    // Optional type annotation.
-    if (scope_->typed() && Check(Token::COLON)) {
-      typename TypeSystem::Type type = ParseValidType(CHECK_OK);
-      USE(type);
+    // Parse optional type annotation.
+    typename TypeSystem::Type type = this->EmptyType();
+    if (scope_->typed() && Check(Token::COLON)) {  // Braces required here.
+      type = ParseValidType(CHECK_OK);
     }
+    USE(type);  // TODO(nikolaos): really use it!
 
     Scanner::Location variable_loc = scanner()->location();
     const AstRawString* single_name =
         pattern->IsVariableProxy() ? pattern->AsVariableProxy()->raw_name()
                                    : nullptr;
     if (single_name != nullptr) {
       if (fni_ != NULL) fni_->PushVariableName(single_name);
     }
 
     Expression* value = NULL;
@@ skipping 1676 matching lines @@
     DCHECK(reindexer.count() <=
            parser_->function_state_->materialized_literal_count());
   }
 }
 
 
 FunctionLiteral* Parser::ParseFunctionLiteral(
     const AstRawString* function_name, Scanner::Location function_name_location,
     FunctionNameValidity function_name_validity, FunctionKind kind,
     int function_token_pos, FunctionLiteral::FunctionType function_type,
-    LanguageMode language_mode, bool* ok) {
+    LanguageMode language_mode, typesystem::TypeFlags type_flags, bool* ok) {
   // Function ::
   //   '(' FormalParameterList? ')' '{' FunctionBody '}'
   //
   // Getter ::
   //   '(' ')' '{' FunctionBody '}'
   //
   // Setter ::
   //   '(' PropertySetParameterList ')' '{' FunctionBody '}'
 
   int pos = function_token_pos == RelocInfo::kNoPosition
@@ skipping 74 matching lines @@
       scope_->ForceContextAllocation();
 
       // Calling a generator returns a generator object.  That object is stored
       // in a temporary variable, a definition that is used by "yield"
       // expressions. This also marks the FunctionState as a generator.
       Variable* temp = scope_->NewTemporary(
           ast_value_factory()->dot_generator_object_string());
       function_state.set_generator_object_variable(temp);
     }
 
+    // Parse optional type parameters.
+    typename TypeSystem::TypeParameters type_parameters =
+        this->NullTypeParameters();
+    if (scope_->typed() &&
+        !(type_flags & typesystem::kDisallowTypeParameters) &&
+        peek() == Token::LT) {  // Braces required here.
+      type_parameters = ParseTypeParameters(CHECK_OK);
+    }
+    USE(type_parameters);  // TODO(nikolaos): really use them!
+
     Expect(Token::LPAREN, CHECK_OK);
     int start_position = scanner()->location().beg_pos;
     scope_->set_start_position(start_position);
     ParserFormalParameters formals(scope);
     ParseFormalParameterList(&formals, &formals_classifier, CHECK_OK);
     arity = formals.Arity();
     Expect(Token::RPAREN, CHECK_OK);
     int formals_end_position = scanner()->location().end_pos;
 
     CheckArityRestrictions(arity, kind, formals.has_rest, start_position,
                            formals_end_position, CHECK_OK);
+
+    // Parse optional type annotation.
+    typename TypeSystem::Type result_type = this->EmptyType();
+    if (scope_->typed() &&
+        !(type_flags & typesystem::kDisallowTypeAnnotation) &&
+        Check(Token::COLON)) {  // Braces required here.
+      result_type = ParseValidType(CHECK_OK);
+    }
+    USE(result_type);  // TODO(nikolaos): really use it!
+
+    // Allow for a function signature (i.e., a literal without body).
+    // In that case, return a nullptr instead of a function literal.

[rossberg, 2016/04/18 09:22:24]

May be worth documenting at the funciton declaration that it may return null.

[nickie, 2016/04/19 10:58:10]

Done.

+    if (peek() != Token::LBRACE && scope_->typed() &&
+        (type_flags & typesystem::kAllowSignature)) {
+      ExpectSemicolon(CHECK_OK);
+      return nullptr;
+    }
+
     Expect(Token::LBRACE, CHECK_OK);
 
     // Don't include the rest parameter into the function's formal parameter
     // count (esp. the SharedFunctionInfo::internal_formal_parameter_count,
     // which says whether we need to create an arguments adaptor frame).
     if (formals.has_rest) arity--;
 
     // Determine if the function can be parsed lazily. Lazy parsing is different
     // from lazy compilation; we need to parse more eagerly than we compile.
 
@@ skipping 2730 matching lines @@
                         try_block, target);
     final_loop = target;
   }
 
   return final_loop;
 }
 
 
 }  // namespace internal
 }  // namespace v8