C++ ParserResult::isNonNull方法代码示例

/// parseTypeComposition
///   
///   type-composition:
///     'protocol' '<' type-composition-list? '>'
///
///   type-composition-list:
///     type-identifier (',' type-identifier)*
///
ParserResult<ProtocolCompositionTypeRepr> Parser::parseTypeComposition() {
  SourceLoc ProtocolLoc = consumeToken(tok::kw_protocol);
 
  // Check for the starting '<'.
  if (!startsWithLess(Tok)) {
    diagnose(Tok, diag::expected_langle_protocol);
    return nullptr;
  }
  SourceLoc LAngleLoc = consumeStartingLess();
  
  // Check for empty protocol composition.
  if (startsWithGreater(Tok)) {
    SourceLoc RAngleLoc = consumeStartingGreater();
    return makeParserResult(new (Context) ProtocolCompositionTypeRepr(
                                             ArrayRef<IdentTypeRepr *>(),
                                             ProtocolLoc,
                                             SourceRange(LAngleLoc,
                                                         RAngleLoc)));
  }
  
  // Parse the type-composition-list.
  ParserStatus Status;
  SmallVector<IdentTypeRepr *, 4> Protocols;
  do {
    // Parse the type-identifier.
    ParserResult<IdentTypeRepr> Protocol = parseTypeIdentifier();
    Status |= Protocol;
    if (Protocol.isNonNull())
      Protocols.push_back(Protocol.get());
  } while (consumeIf(tok::comma));
  
  // Check for the terminating '>'.
  SourceLoc EndLoc = PreviousLoc;
  if (startsWithGreater(Tok)) {
    EndLoc = consumeStartingGreater();
  } else {
    if (Status.isSuccess()) {
      diagnose(Tok, diag::expected_rangle_protocol);
      diagnose(LAngleLoc, diag::opening_angle);
      Status.setIsParseError();
    }

    // Skip until we hit the '>'.
    EndLoc = skipUntilGreaterInTypeList(/*protocolComposition=*/true);
  }

  return makeParserResult(Status, ProtocolCompositionTypeRepr::create(
      Context, Protocols, ProtocolLoc, SourceRange(LAngleLoc, EndLoc)));
}

ParserResult<GenericParamList>
Parser::parseGenericParameters(SourceLoc LAngleLoc) {
  // Parse the generic parameter list.
  SmallVector<GenericTypeParamDecl *, 4> GenericParams;
  bool Invalid = false;
  do {
    // Note that we're parsing a declaration.
    StructureMarkerRAII ParsingDecl(*this, Tok.getLoc(),
                                    StructureMarkerKind::Declaration);

    // Parse attributes.
    DeclAttributes attributes;
    if (Tok.hasComment())
      attributes.add(new (Context) RawDocCommentAttr(Tok.getCommentRange()));
    bool foundCCTokenInAttr;
    parseDeclAttributeList(attributes, foundCCTokenInAttr);

    // Parse the name of the parameter.
    Identifier Name;
    SourceLoc NameLoc;
    if (parseIdentifier(Name, NameLoc,
                        diag::expected_generics_parameter_name)) {
      Invalid = true;
      break;
    }

    // Parse the ':' followed by a type.
    SmallVector<TypeLoc, 1> Inherited;
    if (Tok.is(tok::colon)) {
      (void)consumeToken();
      ParserResult<TypeRepr> Ty;
      
      if (Tok.isAny(tok::identifier, tok::code_complete, tok::kw_protocol, tok::kw_Any)) {
        Ty = parseTypeIdentifierOrTypeComposition();
      } else if (Tok.is(tok::kw_class)) {
        diagnose(Tok, diag::unexpected_class_constraint);
        diagnose(Tok, diag::suggest_anyobject, Name)
          .fixItReplace(Tok.getLoc(), "AnyObject");
        consumeToken();
        Invalid = true;
      } else {
        diagnose(Tok, diag::expected_generics_type_restriction, Name);
        Invalid = true;
      }

      if (Ty.hasCodeCompletion())
        return makeParserCodeCompletionStatus();

      if (Ty.isNonNull())
        Inherited.push_back(Ty.get());
    }

    // We always create generic type parameters with a depth of zero.
    // Semantic analysis fills in the depth when it processes the generic
    // parameter list.
    auto Param = new (Context) GenericTypeParamDecl(CurDeclContext, Name,
                                                    NameLoc, /*Depth=*/0,
                                                    GenericParams.size());
    if (!Inherited.empty())
      Param->setInherited(Context.AllocateCopy(Inherited));
    GenericParams.push_back(Param);

    // Attach attributes.
    Param->getAttrs() = attributes;

    // Add this parameter to the scope.
    addToScope(Param);

    // Parse the comma, if the list continues.
  } while (consumeIf(tok::comma));

  // Parse the optional where-clause.
  SourceLoc WhereLoc;
  SmallVector<RequirementRepr, 4> Requirements;
  bool FirstTypeInComplete;
  if (Tok.is(tok::kw_where) &&
      parseGenericWhereClause(WhereLoc, Requirements,
                              FirstTypeInComplete).isError()) {
    Invalid = true;
  }
  
  // Parse the closing '>'.
  SourceLoc RAngleLoc;
  if (!startsWithGreater(Tok)) {
    if (!Invalid) {
      diagnose(Tok, diag::expected_rangle_generics_param);
      diagnose(LAngleLoc, diag::opening_angle);
      
      Invalid = true;
    }
    
    // Skip until we hit the '>'.
    skipUntilGreaterInTypeList();
    if (startsWithGreater(Tok))
      RAngleLoc = consumeStartingGreater();
    else
      RAngleLoc = Tok.getLoc();
  } else {
    RAngleLoc = consumeStartingGreater();
  }
//.........这里部分代码省略.........

/// parseTypeSimple
///   type-simple:
///     type-identifier
///     type-tuple
///     type-composition
///     'Any'
///     type-simple '.Type'
///     type-simple '.Protocol'
///     type-simple '?'
///     type-simple '!'
///     type-collection
ParserResult<TypeRepr> Parser::parseTypeSimple(Diag<> MessageID,
                                               bool HandleCodeCompletion) {
  ParserResult<TypeRepr> ty;
  // If this is an "inout" marker for an identifier type, consume the inout.
  SourceLoc InOutLoc;
  consumeIf(tok::kw_inout, InOutLoc);

  switch (Tok.getKind()) {
  case tok::kw_Self:
    ty = parseTypeIdentifier();
    break;
  case tok::identifier:
  case tok::kw_protocol:
  case tok::kw_Any:
    ty = parseTypeIdentifierOrTypeComposition();
    break;
  case tok::l_paren:
    ty = parseTypeTupleBody();
    break;
  case tok::code_complete:
    if (!HandleCodeCompletion)
      break;
    if (CodeCompletion)
      CodeCompletion->completeTypeSimpleBeginning();
    // Eat the code completion token because we handled it.
    consumeToken(tok::code_complete);
    return makeParserCodeCompletionResult<TypeRepr>();
  case tok::kw_super:
  case tok::kw_self:
    // These keywords don't start a decl or a statement, and thus should be
    // safe to skip over.
    diagnose(Tok, MessageID);
    ty = makeParserErrorResult(new (Context) ErrorTypeRepr(Tok.getLoc()));
    consumeToken();
    // FIXME: we could try to continue to parse.
    return ty;
  case tok::l_square:
    ty = parseTypeCollection();
    break;
  default:
    checkForInputIncomplete();
    diagnose(Tok, MessageID);
    return nullptr;
  }
  
  // '.Type', '.Protocol', '?', and '!' still leave us with type-simple.
  while (ty.isNonNull()) {
    if ((Tok.is(tok::period) || Tok.is(tok::period_prefix))) {
      if (peekToken().isContextualKeyword("Type")) {
        consumeToken();
        SourceLoc metatypeLoc = consumeToken(tok::identifier);
        ty = makeParserResult(ty,
          new (Context) MetatypeTypeRepr(ty.get(), metatypeLoc));
        continue;
      }
      if (peekToken().isContextualKeyword("Protocol")) {
        consumeToken();
        SourceLoc protocolLoc = consumeToken(tok::identifier);
        ty = makeParserResult(ty,
          new (Context) ProtocolTypeRepr(ty.get(), protocolLoc));
        continue;
      }
    }

    if (!Tok.isAtStartOfLine()) {
      if (isOptionalToken(Tok)) {
        ty = parseTypeOptional(ty.get());
        continue;
      }
      if (isImplicitlyUnwrappedOptionalToken(Tok)) {
        ty = parseTypeImplicitlyUnwrappedOptional(ty.get());
        continue;
      }
    }
    break;
  }

  // If we parsed an inout modifier, prepend it.
  if (InOutLoc.isValid())
    ty = makeParserResult(new (Context) InOutTypeRepr(ty.get(),
                                                      InOutLoc));

  return ty;
}

/// parseType
///   type:
///     attribute-list type-function
///     attribute-list type-array
///
///   type-function:
///     type-simple '->' type
///
ParserResult<TypeRepr> Parser::parseType(Diag<> MessageID,
                                         bool HandleCodeCompletion) {
  // Parse attributes.
  TypeAttributes attrs;
  parseTypeAttributeList(attrs);

  // Parse Generic Parameters. Generic Parameters are visible in the function
  // body.
  GenericParamList *generics = nullptr;
  if (isInSILMode()) {
    generics = maybeParseGenericParams().getPtrOrNull();
  }

  ParserResult<TypeRepr> ty = parseTypeSimple(MessageID, HandleCodeCompletion);
  if (ty.hasCodeCompletion())
    return makeParserCodeCompletionResult<TypeRepr>();

  if (ty.isNull())
    return nullptr;

  // Parse a throws specifier.  'throw' is probably a typo for 'throws',
  // but in local contexts we could just be at the end of a statement,
  // so we need to check for the arrow.
  ParserPosition beforeThrowsPos;
  SourceLoc throwsLoc;
  bool rethrows = false;
  if (Tok.isAny(tok::kw_throws, tok::kw_rethrows) ||
      (Tok.is(tok::kw_throw) && peekToken().is(tok::arrow))) {
    if (Tok.is(tok::kw_throw)) {
      diagnose(Tok.getLoc(), diag::throw_in_function_type)
        .fixItReplace(Tok.getLoc(), "throws");
    }

    beforeThrowsPos = getParserPosition();
    rethrows = Tok.is(tok::kw_rethrows);
    throwsLoc = consumeToken();
  }

  // Handle type-function if we have an arrow.
  SourceLoc arrowLoc;
  if (consumeIf(tok::arrow, arrowLoc)) {
    ParserResult<TypeRepr> SecondHalf =
      parseType(diag::expected_type_function_result);
    if (SecondHalf.hasCodeCompletion())
      return makeParserCodeCompletionResult<TypeRepr>();
    if (SecondHalf.isNull())
      return nullptr;
    if (rethrows) {
      // 'rethrows' is only allowed on function declarations for now.
      diagnose(throwsLoc, diag::rethrowing_function_type);
    }
    auto fnTy = new (Context) FunctionTypeRepr(generics, ty.get(),
                                               throwsLoc,
                                               arrowLoc,
                                               SecondHalf.get());
    return makeParserResult(applyAttributeToType(fnTy, attrs));
  } else if (throwsLoc.isValid()) {
    // Don't consume 'throws', so we can emit a more useful diagnostic when
    // parsing a function decl.
    restoreParserPosition(beforeThrowsPos);
    return ty;
  }
  
  // Only function types may be generic.
  if (generics) {
    auto brackets = generics->getSourceRange();
    diagnose(brackets.Start, diag::generic_non_function);
  }

  // Parse legacy array types for migration.
  while (ty.isNonNull() && !Tok.isAtStartOfLine()) {
    if (Tok.is(tok::l_square)) {
      ty = parseTypeArray(ty.get());
    } else {
      break;
    }
  }

  if (ty.isNonNull() && !ty.hasCodeCompletion()) {
    ty = makeParserResult(applyAttributeToType(ty.get(), attrs));
  }
  return ty;
}

GenericParamList *Parser::parseGenericParameters(SourceLoc LAngleLoc) {
  // Parse the generic parameter list.
  SmallVector<GenericTypeParamDecl *, 4> GenericParams;
  bool Invalid = false;
  do {
    // Parse the name of the parameter.
    Identifier Name;
    SourceLoc NameLoc;
    if (parseIdentifier(Name, NameLoc, diag::expected_generics_parameter_name)) {
      Invalid = true;
      break;
    }

    // Parse the ':' followed by a type.
    SmallVector<TypeLoc, 1> Inherited;
    if (Tok.is(tok::colon)) {
      (void)consumeToken();
      ParserResult<TypeRepr> Ty;
      if (Tok.getKind() == tok::identifier) {
        Ty = parseTypeIdentifier();
      } else if (Tok.getKind() == tok::kw_protocol) {
        Ty = parseTypeComposition();
      } else {
        diagnose(Tok, diag::expected_generics_type_restriction, Name);
        Invalid = true;
      }

      // FIXME: code completion not handled.
      if (Ty.isNonNull())
        Inherited.push_back(Ty.get());
    }

    // We always create generic type parameters with a depth of zero.
    // Semantic analysis fills in the depth when it processes the generic
    // parameter list.
    auto Param = new (Context) GenericTypeParamDecl(CurDeclContext, Name,
                                                    NameLoc, /*Depth=*/0,
                                                    GenericParams.size());
    if (!Inherited.empty())
      Param->setInherited(Context.AllocateCopy(Inherited));
    GenericParams.push_back(Param);

    // Add this parameter to the scope.
    addToScope(Param);

    // Parse the comma, if the list continues.
  } while (consumeIf(tok::comma));

  // Parse the optional where-clause.
  SourceLoc WhereLoc;
  SmallVector<RequirementRepr, 4> Requirements;
  if (Tok.is(tok::kw_where) &&
      parseGenericWhereClause(WhereLoc, Requirements)) {
    Invalid = true;
  }
  
  // Parse the closing '>'.
  SourceLoc RAngleLoc;
  if (!startsWithGreater(Tok)) {
    if (!Invalid) {
      diagnose(Tok, diag::expected_rangle_generics_param);
      diagnose(LAngleLoc, diag::opening_angle);
      
      Invalid = true;
    }
    
    // Skip until we hit the '>'.
    skipUntilGreaterInTypeList();
    if (startsWithGreater(Tok))
      RAngleLoc = consumeStartingGreater();
    else
      RAngleLoc = Tok.getLoc();
  } else {
    RAngleLoc = consumeStartingGreater();
  }

  if (GenericParams.empty())
    return nullptr;

  return GenericParamList::create(Context, LAngleLoc, GenericParams,
                                  WhereLoc, Requirements, RAngleLoc);
}

static ParserStatus parseDefaultArgument(Parser &P,
                                   Parser::DefaultArgumentInfo *defaultArgs,
                                   unsigned argIndex,
                                   ExprHandle *&init,
                                 Parser::ParameterContextKind paramContext) {
  SourceLoc equalLoc = P.consumeToken(tok::equal);

  // Enter a fresh default-argument context with a meaningless parent.
  // We'll change the parent to the function later after we've created
  // that declaration.
  auto initDC =
    P.Context.createDefaultArgumentContext(P.CurDeclContext, argIndex);
  Parser::ParseFunctionBody initScope(P, initDC);

  ParserResult<Expr> initR = P.parseExpr(diag::expected_init_value);

  // Give back the default-argument context if we didn't need it.
  if (!initScope.hasClosures()) {
    P.Context.destroyDefaultArgumentContext(initDC);

  // Otherwise, record it if we're supposed to accept default
  // arguments here.
  } else if (defaultArgs) {
    defaultArgs->ParsedContexts.push_back(initDC);
  }

  Diag<> diagID = { DiagID() };
  switch (paramContext) {
  case Parser::ParameterContextKind::Function:
  case Parser::ParameterContextKind::Operator:
  case Parser::ParameterContextKind::Initializer:
    break;
  case Parser::ParameterContextKind::Closure:
    diagID = diag::no_default_arg_closure;
    break;
  case Parser::ParameterContextKind::Subscript:
    diagID = diag::no_default_arg_subscript;
    break;
  case Parser::ParameterContextKind::Curried:
    diagID = diag::no_default_arg_curried;
    break;
  }
  
  assert(((diagID.ID != DiagID()) == !defaultArgs ||
          // Sometimes curried method parameter lists get default arg info.
          // Remove this when they go away.
          paramContext == Parser::ParameterContextKind::Curried) &&
         "Default arguments specified for an unexpected parameter list kind");
  
  if (diagID.ID != DiagID()) {
    auto inFlight = P.diagnose(equalLoc, diagID);
    if (initR.isNonNull())
      inFlight.fixItRemove(SourceRange(equalLoc, initR.get()->getEndLoc()));
    return ParserStatus();
  }
  
  defaultArgs->HasDefaultArgument = true;

  if (initR.hasCodeCompletion())
    return makeParserCodeCompletionStatus();

  if (initR.isNull())
    return makeParserError();

  init = ExprHandle::get(P.Context, initR.get());
  return ParserStatus();
}

ParserStatus
Parser::parseGenericParametersBeforeWhere(SourceLoc LAngleLoc,
                        SmallVectorImpl<GenericTypeParamDecl *> &GenericParams) {
  ParserStatus Result;
  SyntaxParsingContext GPSContext(SyntaxContext, SyntaxKind::GenericParameterList);
  bool HasNextParam;
  do {
    SyntaxParsingContext GParamContext(SyntaxContext, SyntaxKind::GenericParameter);
    // Note that we're parsing a declaration.
    StructureMarkerRAII ParsingDecl(*this, Tok.getLoc(),
                                    StructureMarkerKind::Declaration);
    
    if (ParsingDecl.isFailed()) {
      return makeParserError();
    }

    // Parse attributes.
    DeclAttributes attributes;
    if (Tok.hasComment())
      attributes.add(new (Context) RawDocCommentAttr(Tok.getCommentRange()));
    bool foundCCTokenInAttr;
    parseDeclAttributeList(attributes, foundCCTokenInAttr);

    // Parse the name of the parameter.
    Identifier Name;
    SourceLoc NameLoc;
    if (parseIdentifier(Name, NameLoc,
                        diag::expected_generics_parameter_name)) {
      Result.setIsParseError();
      break;
    }

    // Parse the ':' followed by a type.
    SmallVector<TypeLoc, 1> Inherited;
    if (Tok.is(tok::colon)) {
      (void)consumeToken();
      ParserResult<TypeRepr> Ty;

      if (Tok.isAny(tok::identifier, tok::code_complete, tok::kw_protocol,
                    tok::kw_Any)) {
        Ty = parseType();
      } else if (Tok.is(tok::kw_class)) {
        diagnose(Tok, diag::unexpected_class_constraint);
        diagnose(Tok, diag::suggest_anyobject)
        .fixItReplace(Tok.getLoc(), "AnyObject");
        consumeToken();
        Result.setIsParseError();
      } else {
        diagnose(Tok, diag::expected_generics_type_restriction, Name);
        Result.setIsParseError();
      }

      if (Ty.hasCodeCompletion())
        return makeParserCodeCompletionStatus();

      if (Ty.isNonNull())
        Inherited.push_back(Ty.get());
    }

    // We always create generic type parameters with an invalid depth.
    // Semantic analysis fills in the depth when it processes the generic
    // parameter list.
    auto Param = new (Context) GenericTypeParamDecl(CurDeclContext, Name, NameLoc,
                                            GenericTypeParamDecl::InvalidDepth,
                                                    GenericParams.size());
    if (!Inherited.empty())
      Param->setInherited(Context.AllocateCopy(Inherited));
    GenericParams.push_back(Param);

    // Attach attributes.
    Param->getAttrs() = attributes;

    // Add this parameter to the scope.
    addToScope(Param);

    // Parse the comma, if the list continues.
    HasNextParam = consumeIf(tok::comma);
  } while (HasNextParam);

  return Result;
}