clang-format is a de facto standard tool to auto format (C++) code with style described by .clang-format file that typically located inside your project's root directory. AUI has such file.

Since AUI abuses C++'s syntax, it's important to set up appropriate auto formatting, or you will often find yourself struggling with AUI's DSL especially in large portions of layout, despite the fact we recommend to decompose large AUI DSLs into smaller pieces (i.e., functions). For your project, we recommend to start with AUI's formatting configuration listed below. AUI's App Template has .clang-format already. Your IDE should pick up it without further configuration.

Always Use Trailing Comma in Initializer Lists#

When it comes to clang-format there's one an unobvious feature when using AUI's DSL. Consider the example:

With Trailing Comma	Without Trailing Comma
setContents(Vertical { Button { "Up" }, Button { "Down" }, });	setContents(Vertical { Button { "Up" }, Button { "Down" } });

See the difference? The second example lacks one comma. If we try to trigger clang-format (ALT+CTRL+L in CLion), we'll get the following results (assuming AUI's .clang-format):

With Trailing Comma	Without Trailing Comma
setContents(Vertical { Button { "Up" }, Button { "Down" }, });	setContents(Vertical { Button { "Up" }, Button { "Down" } });

The first example left as is (correct), the second example formatted confusingly.

When using any kind of AUI's DSL with initializer lists please always use trailing comma. Not only it helps with reordering, git diffs, etc..., but also .clang-format makes proper formatting for lists with trailing commas.

Use clang-format off/on#

In some scenarios clang-format may fight against you, especially with complicated syntax. You can use // clang-format off and // clang-format on to disable and enable clang-format, respectively.

struct DataOptional {
    int v1;
    int v2;
};
 
// clang-format off
AJSON_FIELDS(DataOptional,
             (v1, "v1")
             (v2, "v2", AJsonFieldFlags::OPTIONAL))
// clang-format on

AUI's .clang-format#

Place this .clang-format file in root of your project.

# options: https://clang.llvm.org/docs/ClangFormatStyleOptions.html
BasedOnStyle: Google
IndentWidth: 4
ColumnLimit: 120
# does (int) x instead of (int)x
SpaceAfterCStyleCast: true
# spaces, not tabs!
UseTab: Never
# if (x) doStuff()  is not allowed, bad style
AllowShortIfStatementsOnASingleLine: false
AlignTrailingComments: true
SpacesBeforeTrailingComments: 3
AlignConsecutiveMacros: Consecutive
 
# use \n instead of \r\n
UseCRLF: false
 
AccessModifierOffset: -4
EmptyLineBeforeAccessModifier: Always
EmptyLineAfterAccessModifier: Never
 
NamespaceIndentation: None
BreakConstructorInitializers: BeforeComma
 
# we have some problems with ranges-v3 and AUI's let, so keep it disabled
SortIncludes: Never
 
 
################################################# UI BUILDING ##########################################################
 
# use shorter indentation for UI building stuff (like in Dart/Flutter)
BracedInitializerIndentWidth: 2
ConstructorInitializerIndentWidth: 2
 
# better spacing around with_style and let.
# before:
# view with_style{Expanding()},
# view let{printf("Hello");},
#
# after:
# view with_style { Expanding() },
# view let { printf("Hello"); },
Cpp11BracedListStyle: false
SpaceBeforeCpp11BracedList: true
 
# forces nested initializer lists to begin with their own lines.
# note: you should use comma after last element in initializer lists.
# before:
# Centered { Horizontal {
#
# after:
# Centered {
#   Horizontal {
PenaltyIndentedWhitespace: 1000
BreakBeforeBraces: Attach
BreakBeforeBinaryOperators: None
  
StatementAttributeLikeMacros:
  - emit
 
# fix AUI's scary macros.
Macros:
  - let=+[]
  - async=[]
  - AUI_DECLARATIVE_FOR(a,b,c)=[v2=b,v3=c](a)
  - AUI_DECLARATIVE_FOR_EX(a,b,c,d)=[d,v2=b,v3=c](a)
  - with_style=+std::vector