C++ ParserStatus::isSuccess方法代码示例

/// Parse a pattern with an optional type annotation.
///
///  typed-pattern ::= pattern (':' type)?
///
ParserResult<Pattern> Parser::parseTypedPattern() {
  auto result = parsePattern();
  
  // Now parse an optional type annotation.
  if (Tok.is(tok::colon)) {
    SourceLoc colonLoc = consumeToken(tok::colon);
    
    if (result.isNull())  // Recover by creating AnyPattern.
      result = makeParserErrorResult(new (Context) AnyPattern(colonLoc));
    
    ParserResult<TypeRepr> Ty = parseType();
    if (Ty.hasCodeCompletion())
      return makeParserCodeCompletionResult<Pattern>();
    if (!Ty.isNull()) {
      // Attempt to diagnose initializer calls incorrectly written
      // as typed patterns, such as "var x: [Int]()".
      if (Tok.isFollowingLParen()) {
        BacktrackingScope backtrack(*this);
        
        // Create a local context if needed so we can parse trailing closures.
        LocalContext dummyContext;
        Optional<ContextChange> contextChange;
        if (!CurLocalContext) {
          contextChange.emplace(*this, CurDeclContext, &dummyContext);
        }
        
        SourceLoc lParenLoc, rParenLoc;
        SmallVector<Expr *, 2> args;
        SmallVector<Identifier, 2> argLabels;
        SmallVector<SourceLoc, 2> argLabelLocs;
        Expr *trailingClosure;
        ParserStatus status = parseExprList(tok::l_paren, tok::r_paren,
                                            /*isPostfix=*/true,
                                            /*isExprBasic=*/false,
                                            lParenLoc, args, argLabels,
                                            argLabelLocs, rParenLoc,
                                            trailingClosure);
        if (status.isSuccess()) {
          backtrack.cancelBacktrack();
          
          // Suggest replacing ':' with '='
          diagnose(lParenLoc, diag::initializer_as_typed_pattern)
            .highlight({Ty.get()->getStartLoc(), rParenLoc})
            .fixItReplace(colonLoc, " = ");
          result.setIsParseError();
        }
      }
    } else {
      Ty = makeParserResult(new (Context) ErrorTypeRepr(PreviousLoc));
    }
    
    result = makeParserResult(result,
                            new (Context) TypedPattern(result.get(), Ty.get()));
  }
  
  return result;
}

/// 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)));
}

/// parseTypeIdentifierOrTypeComposition
/// - Identifiers and compositions both start with the same identifier
///   token, parse it and continue constructing a composition if the
///   next token is '&'
///
///   type-composition:
///     type-identifier ('&' type-identifier)*
///     'protocol' '<' type-composition-list-deprecated? '>'
///
///   type-composition-list-deprecated:
///     type-identifier (',' type-identifier)*
ParserResult<TypeRepr> Parser::parseTypeIdentifierOrTypeComposition() {
  
  // Handle deprecated case
  if (Tok.getKind() == tok::kw_protocol && startsWithLess(peekToken())) {
    SourceLoc ProtocolLoc = consumeToken(tok::kw_protocol);
    SourceLoc LAngleLoc = consumeStartingLess();
    
    // Parse the type-composition-list.
    ParserStatus Status;
    SmallVector<IdentTypeRepr *, 4> Protocols;
    bool IsEmpty = startsWithGreater(Tok);
    if (!IsEmpty) {
      do {
        // Parse the type-identifier.
        ParserResult<TypeRepr> Protocol = parseTypeIdentifier();
        Status |= Protocol;
        if (auto *ident = dyn_cast_or_null<IdentTypeRepr>(
                                                       Protocol.getPtrOrNull()))
          Protocols.push_back(ident);
      } while (consumeIf(tok::comma));
    }

    // Check for the terminating '>'.
    SourceLoc RAngleLoc = PreviousLoc;
    if (startsWithGreater(Tok)) {
      RAngleLoc = consumeStartingGreater();
    } else {
      if (Status.isSuccess()) {
        diagnose(Tok, diag::expected_rangle_protocol);
        diagnose(LAngleLoc, diag::opening_angle);
        Status.setIsParseError();
      }
      
      // Skip until we hit the '>'.
      RAngleLoc = skipUntilGreaterInTypeList(/*protocolComposition=*/true);
    }

    auto composition = ProtocolCompositionTypeRepr::create(
      Context, Protocols, ProtocolLoc, {LAngleLoc, RAngleLoc});

    if (Status.isSuccess()) {
      // Only if we have complete protocol<...> construct, diagnose deprecated.

      SmallString<32> replacement;
      if (Protocols.empty()) {
        replacement = "Any";
      } else {
        auto extractText = [&](IdentTypeRepr *Ty) -> StringRef {
          auto SourceRange = Ty->getSourceRange();
          return SourceMgr.extractText(
            Lexer::getCharSourceRangeFromSourceRange(SourceMgr, SourceRange));
        };
        auto Begin = Protocols.begin();
        replacement += extractText(*Begin);
        while (++Begin != Protocols.end()) {
          replacement += " & ";
          replacement += extractText(*Begin);
        }
      }

      // Copy trailing content after '>' to the replacement string.
      // FIXME: lexer should smartly separate '>' and trailing contents like '?'.
      StringRef TrailingContent = L->getTokenAt(RAngleLoc).getRange().str().
        substr(1);
      if (!TrailingContent.empty()) {
        if (Protocols.size() > 1) {
          replacement.insert(replacement.begin(), '(');
          replacement += ")";
        }
        replacement += TrailingContent;
      }

      // Replace 'protocol<T1, T2>' with 'T1 & T2'
      diagnose(ProtocolLoc,
        IsEmpty              ? diag::deprecated_any_composition :
        Protocols.size() > 1 ? diag::deprecated_protocol_composition :
                               diag::deprecated_protocol_composition_single)
        .highlight(composition->getSourceRange())
        .fixItReplace(composition->getSourceRange(), replacement);
    }

    return makeParserResult(Status, composition);
  }
  
  SourceLoc FirstTypeLoc = Tok.getLoc();
  
  // Parse the first type
  ParserResult<TypeRepr> FirstType = parseTypeIdentifier();
  if (!Tok.isContextualPunctuator("&"))
//.........这里部分代码省略.........