Clang-format array initializer one per line

Question

Clang-format, given an array of structs with initializers, is putting two items per line:

sym keywords[] = {
 {0, 0, "C"}, {0, 0, "T"},
 {0, 0, "V"}, {0, 0, "ax"},
 {0, 0, "bool"}, {0, 0, "break"},
 ...
 {0, 0, "val"}, {0, 0, "vector"},
 {0, 0, "version"}, {0, 0, "void"},
 {0, 0, "while"},
};

How can I get it to just put one item per line?

clang-format, array initialisers is the closest I have been able to find to a discussion of this problem, but neither of the proposed solutions has any effect; Cpp11BracedListStyle: false does the same thing except with extra spaces between the braces, and as you can see in the above, making sure there is a comma after the last item, doesn't help.

• Ted: hi did you find any solution? any update?
• rwallace: @Ted Erm, the solution I found was to switch the project that was complex enough to generate such constructs from C++ to Java (for other reasons, granted), that's probably not very useful from your perspective, sorry!
• Arsenal: @Ted I might have a solution, not sure if you are still interested.
• Marek R: Try: PackConstructorInitializersStyle value CurrentLine. This requires clang-format 14.

Answer 1

I'm not entirely sure, but ArrayInitializerAlignmentStyle set to left might achieve that result. This option was added with clang-format version 13.

At least my current settings turn your code into:

sym keywords[] = {
 {0, 0, "C" },
 {0, 0, "T" },
 {0, 0, "V" },
 {0, 0, "ax" },
 {0, 0, "bool" },
 {0, 0, "break" },
 {0, 0, "val" },
 {0, 0, "vector" },
 {0, 0, "version"},
 {0, 0, "void" },
 {0, 0, "while" },
};

If I remove that setting I get something similar to your result.

My current settings, which probably don't do what you expect them at other locations:

---
AlignAfterOpenBracket: Align
AlignArrayOfStructures: Left
AlignConsecutiveAssignments: true
AlignConsecutiveDeclarations: true
AlignConsecutiveMacros: true
AlignEscapedNewlines: Left
AlignOperands: true
AlignTrailingComments: true
AllowShortBlocksOnASingleLine: false
AllowShortCaseLabelsOnASingleLine: false
AllowShortFunctionsOnASingleLine: None
AllowShortIfStatementsOnASingleLine: Never
AllowShortLambdasOnASingleLine: None
AllowShortLoopsOnASingleLine: false
BreakBeforeBraces: Allman
BreakConstructorInitializers: AfterColon
BreakInheritanceList: AfterColon
ColumnLimit: 120
EmptyLineBeforeAccessModifier: Always
FixNamespaceComments: true
IncludeBlocks: Regroup
IndentCaseLabels: true
IndentPPDirectives: BeforeHash
IndentWidth: 4
IndentWrappedFunctionNames: true
KeepEmptyLinesAtTheStartOfBlocks: false
MaxEmptyLinesToKeep: 1
PackConstructorInitializers: NextLine
PenaltyBreakAssignment: 10
PenaltyBreakBeforeFirstCallParameter: 10
PenaltyBreakComment: 10
PenaltyBreakFirstLessLess: 10
PenaltyBreakString: 10
PenaltyBreakTemplateDeclaration: 10
PenaltyExcessCharacter: 10
PenaltyReturnTypeOnItsOwnLine: 1000
PointerAlignment: Left
ReflowComments: true
SortUsingDeclarations: true
SpaceAfterCStyleCast: false
SpaceAfterLogicalNot: false
SpaceBeforeAssignmentOperators: true
SpaceBeforeCtorInitializerColon: true
SpaceBeforeInheritanceColon: true
SpaceBeforeParens: ControlStatements
SpacesInCStyleCastParentheses: false
Standard: Latest
TabWidth: 4
UseTab: Never

• zwol: I have clang-format 14.0.0 and your suggestion gives me errors: .clang-format:30:1: error: unknown key 'ArrayInitializerAlignmentStyle'
• bers: @zwol ArrayInitializerAlignmentStyle is not a key, it's the type of the AlignArrayOfStructures setting. So AlignArrayOfStructures: Left is what you are looking for.

Answer 2

The option I found out is BinPackArguments. Setting it to false prevents packing function arguments and array initializer elements onto the same line.