如何用clang-format将长字符串数组格式化为多列形式

问题背景 #

在.h头文件中有一个包含大量字符串的数组，使用Ubuntu clang-format 16.0.6版本时，工具会将每个字符串单独放在一行，导致文件过长难以处理。希望将其格式化为每行包含多个字符串的多列形式，但尝试设置BreakArrays: false后没有效果。

当前代码格式 #

string a[x] = {
    "masfasdno",
    "iasdst",
    "xafdsfayz",
    "pqssssr",
    "mnaado",
    "ist",
    "asdlfkjlkjsad",
    "iasdst",
    "xafasdfsdfsadsfayz",
    "pqssssr",
    "mnaado",
    "ist",
    "asdlfkjlkjsad",
    "kjsakjfksn",
    "lasldfnj",
    "xymnz",
    "pqafr",
    "masfasdno",
    "iasdsadfasdfasdfat",
    "xafdsfayz",
    "pqssssr",
    "mnaado",
    "ist",
    "asdlfkjlkjsad",
    "kjsakjfksn",
    "lasldfnj",
    "xymnz",
    "pqafr",
    "masfasdno",
    "iasdst",
    "xafdsfayz",
    "pqsssadfadasfadfsr",
    "mnaado",
    "ist",
};

期望格式 #

string a[x] = {
    "xymnz",     "masfasdno",   "asjnkjkjb",
    "pqafr",     "masfasdno",   "jnjkbk",
    "masfasdno", "afassaf",     "aksdjfnlkc",
    "iasdst",    "kjbckjasas",  "sajnk",
    "xafdsfayz", "jknkljxakjas","askfnsjdns", 
    "pqssssr",   "skjfkajk",    "akjf",
};

当前clang-format配置 #

---
Language:        Cpp
# BasedOnStyle:  LLVM
AccessModifierOffset: -2
AlignAfterOpenBracket: Align
AlignArrayOfStructures: None
AlignConsecutiveAssignments:
  Enabled:         false
  AcrossEmptyLines: false
  AcrossComments:  false
  AlignCompound:   false
  PadOperators:    true
AlignConsecutiveBitFields:
  Enabled:         false
  AcrossEmptyLines: false
  AcrossComments:  false
  AlignCompound:   false
  PadOperators:    false
AlignConsecutiveDeclarations:
  Enabled:         false
  AcrossEmptyLines: false
  AcrossComments:  false
  AlignCompound:   false
  PadOperators:    false
AlignConsecutiveMacros:
  Enabled:         false
  AcrossEmptyLines: false
  AcrossComments:  false
  AlignCompound:   false
  PadOperators:    false
AlignEscapedNewlines: Right
AlignOperands:   Align
AlignTrailingComments:
  Kind:            Always
  OverEmptyLines:  0
AllowAllArgumentsOnNextLine: true
AllowAllParametersOfDeclarationOnNextLine: true
AllowShortBlocksOnASingleLine: Never
AllowShortCaseLabelsOnASingleLine: false
AllowShortEnumsOnASingleLine: true
AllowShortFunctionsOnASingleLine: All
AllowShortIfStatementsOnASingleLine: Never
AllowShortLambdasOnASingleLine: All
AllowShortLoopsOnASingleLine: false
AlwaysBreakAfterDefinitionReturnType: None
AlwaysBreakAfterReturnType: None
AlwaysBreakBeforeMultilineStrings: false
AlwaysBreakTemplateDeclarations: MultiLine
AttributeMacros:
  - __capability
BinPackArguments: true
BinPackParameters: true
BitFieldColonSpacing: Both
BraceWrapping:
  AfterCaseLabel:  false
  AfterClass:      false
  AfterControlStatement: Never
  AfterEnum:       false
  AfterExternBlock: false
  AfterFunction:   false
  AfterNamespace:  false
  AfterObjCDeclaration: false
  AfterStruct:     false
  AfterUnion:      false
  BeforeCatch:     false
  BeforeElse:      false
  BeforeLambdaBody: false
  BeforeWhile:     false
  IndentBraces:    false
  SplitEmptyFunction: true
  SplitEmptyRecord: true
  SplitEmptyNamespace: true
BreakAfterAttributes: Never
BreakAfterJavaFieldAnnotations: false
BreakArrays:   true 
BreakBeforeBinaryOperators: None
BreakBeforeConceptDeclarations: Always
BreakBeforeBraces: Attach
BreakBeforeInlineASMColon: OnlyMultiline
BreakBeforeTernaryOperators: true
BreakConstructorInitializers: BeforeColon
BreakInheritanceList: BeforeColon
BreakStringLiterals: true
ColumnLimit:     80
CommentPragmas:  '^ IWYU pragma:'
CompactNamespaces: false
ConstructorInitializerIndentWidth: 4
ContinuationIndentWidth: 4
Cpp11BracedListStyle: true
DerivePointerAlignment: false
DisableFormat:   false
EmptyLineAfterAccessModifier: Never
EmptyLineBeforeAccessModifier: LogicalBlock
ExperimentalAutoDetectBinPacking: false
FixNamespaceComments: true
ForEachMacros:
  - foreach
  - Q_FOREACH
  - BOOST_FOREACH
IfMacros:
  - KJ_IF_MAYBE
IncludeBlocks:   Preserve
IncludeCategories:
  - Regex:           '^"(llvm|llvm-c|clang|clang-c)/'
    Priority:        2
    SortPriority:    0
    CaseSensitive:   false
  - Regex:           '^(<|"(gtest|gmock|isl|json)/)'
    Priority:        3
    SortPriority:    0
    CaseSensitive:   false
  - Regex:           '.*'
    Priority:        1
    SortPriority:    0
    CaseSensitive:   false
IncludeIsMainRegex: '(Test)?$'
IncludeIsMainSourceRegex: ''
IndentAccessModifiers: false
IndentCaseBlocks: false
IndentCaseLabels: false
IndentExternBlock: AfterExternBlock
IndentGotoLabels: true
IndentPPDirectives: None
IndentRequiresClause: true
IndentWidth:     2
IndentWrappedFunctionNames: false
InsertBraces:    false
InsertNewlineAtEOF: false
InsertTrailingCommas: None
IntegerLiteralSeparator:
  Binary:          0
  BinaryMinDigits: 0
  Decimal:         0
  DecimalMinDigits: 0
  Hex:             0
  HexMinDigits:    0
JavaScriptQuotes: Leave
JavaScriptWrapImports: true
KeepEmptyLinesAtTheStartOfBlocks: true
LambdaBodyIndentation: Signature
LineEnding:      DeriveLF
MacroBlockBegin: ''
MacroBlockEnd:   ''
MaxEmptyLinesToKeep: 1
NamespaceIndentation: None
ObjCBinPackProtocolList: Auto
ObjCBlockIndentWidth: 2
ObjCBreakBeforeNestedBlockParam: true
ObjCSpaceAfterProperty: false
ObjCSpaceBeforeProtocolList: true
PackConstructorInitializers: BinPack
PenaltyBreakAssignment: 2
PenaltyBreakBeforeFirstCallParameter: 19
PenaltyBreakComment: 300
PenaltyBreakFirstLessLess: 120
PenaltyBreakOpenParenthesis: 0
PenaltyBreakString: 1000
PenaltyBreakTemplateDeclaration: 10
PenaltyExcessCharacter: 1000000
PenaltyIndentedWhitespace: 0
PenaltyReturnTypeOnItsOwnLine: 60
PointerAlignment: Right
PPIndentWidth:   -1
QualifierAlignment: Leave
ReferenceAlignment: Pointer
ReflowComments:  true
RemoveBracesLLVM: false
RemoveSemicolon: false
RequiresClausePosition: OwnLine
RequiresExpressionIndentation: OuterScope
SeparateDefinitionBlocks: Leave
ShortNamespaceLines: 1
SortIncludes:    CaseSensitive
SortJavaStaticImport: Before
SortUsingDeclarations: LexicographicNumeric
SpaceAfterCStyleCast: false
SpaceAfterLogicalNot: false
SpaceAfterTemplateKeyword: true
SpaceAroundPointerQualifiers: Default
SpaceBeforeAssignmentOperators: true
SpaceBeforeCaseColon: false
SpaceBeforeCpp11BracedList: false
SpaceBeforeCtorInitializerColon: true
SpaceBeforeInheritanceColon: true
SpaceBeforeParens: ControlStatements
SpaceBeforeParensOptions:
  AfterControlStatements: true
  AfterForeachMacros: true
  AfterFunctionDefinitionName: false
  AfterFunctionDeclarationName: false
  AfterIfMacros:   true
  AfterOverloadedOperator: false
  AfterRequiresInClause: false
  AfterRequiresInExpression: false
  BeforeNonEmptyParentheses: false
SpaceBeforeRangeBasedForLoopColon: true
SpaceBeforeSquareBrackets: false
SpaceInEmptyBlock: false
SpaceInEmptyParentheses: false
SpacesBeforeTrailingComments: 1
SpacesInAngles:  Never
SpacesInConditionalStatement: false
SpacesInContainerLiterals: true
SpacesInCStyleCastParentheses: false
SpacesInLineCommentPrefix:
  Minimum:         1
  Maximum:         -1
SpacesInParentheses: false
SpacesInSquareBrackets: false
Standard:        Latest
StatementAttributeLikeMacros:
  - Q_EMIT
StatementMacros:
  - Q_UNUSED
  - QT_REQUIRE_VERSION
TabWidth:        8
UseTab:          Never
WhitespaceSensitiveMacros:
  - BOOST_PP_STRINGIZE
  - CF_SWIFT_NAME
  - NS_SWIFT_NAME
  - PP_STRINGIZE
  - STRINGIZE
...

解决方案 #

1. 修正核心配置项 #

你的配置中BreakArrays设为true，这是导致数组元素被强制拆分的核心原因，需要调整以下关键配置：

# 禁止拆分数组元素，允许同一行放多个字符串
BreakArrays: false
# 调大列宽限制，给多列字符串留出足够空间
ColumnLimit: 120
# 关闭C++11花括号列表样式，避免强制换行规则影响数组
Cpp11BracedListStyle: false
# 保持开启，让clang-format倾向于将元素打包到同一行
BinPackArguments: true
BinPackParameters: true

2. 可选对齐优化 #

如果希望字符串自动对齐成整齐的列，可以开启AlignConsecutiveDeclarations（注意该选项会影响其他代码的声明格式）：

AlignConsecutiveDeclarations:
  Enabled: true
  AcrossEmptyLines: false
  AcrossComments: false
  AlignCompound: false
  PadOperators: true

3. 验证配置 #

修改配置后，运行以下命令格式化文件：

clang-format -i your_header_file.h

说明 #

BreakArrays选项直接控制clang-format是否拆分数组元素，设为false后工具会尝试将多个字符串放在同一行，直到达到ColumnLimit的宽度限制。Cpp11BracedListStyle设为false可以避免C++11风格的强制换行规则干扰数组的格式化逻辑。

内容的提问来源于stack exchange，提问作者thirdeye