Noissue - clang-format configuration file for C++

c++/clang-format/clang-format-eyeo

 ---
-Language:        Cpp
-AccessModifierOffset: -2

[sergei, 2017/09/08 15:10:44]

I think we should add
AlignAfterOpenBracket: DontAlign

[Eric, 2017/09/08 15:48:34]

The Mozilla style guide uses examples where the value would be "Align". A dump
of the Mozilla style within `clang-format` has the value "Align". I've added the
"Align" value.

We can change the Eyeo coding style, but that's out of scope for this change.

-AlignEscapedNewlinesLeft: false
-AlignTrailingComments: true
-AllowAllParametersOfDeclarationOnNextLine: false
-AllowShortBlocksOnASingleLine: false
-AllowShortFunctionsOnASingleLine: All
-AllowShortIfStatementsOnASingleLine: false
-AllowShortLoopsOnASingleLine: false
-AlwaysBreakBeforeMultilineStrings: false
-AlwaysBreakTemplateDeclarations: true
+# The syntax herein is for Clang 4, with opt-in support for Clang 5.
+
+Language: Cpp
+BasedOnStyle: Mozilla
+
+# _de facto_ style is no breaking for return types.
+# Clang 5 version
+AlwaysBreakAfterReturnType: None 
+# Clang 4 version
+# Clang 4 documentation defect: It defines "AlwaysBreakAfterReturnType" and 
+# states that "AlwaysBreakAfterDefinitionReturnType" is deprecated. Disregard
+# this; the line below is necessary for Clang 4 and the Clang 5 version need not
+# be commented out.  
+AlwaysBreakAfterDefinitionReturnType: None
+
+# Long function definitions or calls should not become even longer.
+BinPackArguments: true
 BinPackParameters: true
-BreakBeforeBinaryOperators: false
+
+# Non-assignment operators appear at the beginning of line (after indent).
+BreakBeforeBinaryOperators: NonAssignment
+
+# General override: "Opening braces always go on their own line." 
 BreakBeforeBraces: Allman
-BreakBeforeTernaryOperators: false
+
+# Don't treat commas specially within initializers.
+# Clang 5 version
+#BreakConstructorInitializers: BeforeColon
+# Clang 4 version
 BreakConstructorInitializersBeforeComma: false
+
+# Don't wrap long lines automatically.
+# If lines need to be wrapped, do so explicitly. 
 ColumnLimit: 0

[hub, 2017/09/06 14:42:42]

Should we have a column limit like 80 ? it is loosely applied, but 0 make some
line being unwrapped.

[Eric, 2017/09/08 15:48:34]

I tried column limits before, and it wasn't practicable, not at the outset. A
bunch of old code suddenly looked far worse. Lot's of lines that had been ~
81-90 characters got orphaned second lines. Etc.

Since this is an initial commit, it's more conservative not to enforce this one
yet. I'm thinking we need a script wrapper around the use case of reformatting
long lines.

[hub, 2017/09/08 16:02:45]

this actually unwrap manually wrapped lines. So maybe a different approach would
be to ensure it doesn't unwrap. Not sure which option.

-CommentPragmas:  '^ IWYU pragma:'
-ConstructorInitializerAllOnOneLineOrOnePerLine: true
-ConstructorInitializerIndentWidth: 2
-ContinuationIndentWidth: 2
+
+# Format braced lists like function calls.  
 Cpp11BracedListStyle: true
-DerivePointerAlignment: false
-DisableFormat:   false
-ExperimentalAutoDetectBinPacking: false
-ForEachMacros:   [ foreach, Q_FOREACH, BOOST_FOREACH ]
-IndentCaseLabels: false

[hub, 2017/09/06 14:56:51]

This should be "true"

False turns

```
switch ()
{
  case 1:
```

to 

```
switch ()
{
case 1:
```

I have seen the later style though (in a few instances), so we should just
settle on one and set this options accordingly.

[Eric, 2017/09/08 15:48:34]

I changed this one to conform to the Mozilla style guide.

As I recall, this was to deal with legacy ablockplusie code or Visual Studio
default (I forget which) that used the other style.

-IndentFunctionDeclarationAfterType: false
-IndentWidth: 2
-IndentWrappedFunctionNames: false
+
+# Don't preserve excess vertical whitespace. 
 KeepEmptyLinesAtTheStartOfBlocks: false
-MaxEmptyLinesToKeep: 1
+
+# C++ override. "Indent namespace bodies."
 NamespaceIndentation: All
-PenaltyBreakBeforeFirstCallParameter: 19
-PenaltyBreakComment: 300
-PenaltyBreakFirstLessLess: 120
-PenaltyBreakString: 1000
-PenaltyExcessCharacter: 1000000
-PenaltyReturnTypeOnItsOwnLine: 200
-PointerAlignment: Left
-SpaceBeforeAssignmentOperators: true
-SpaceBeforeParens: ControlStatements
-SpaceInEmptyParentheses: false
-SpacesBeforeTrailingComments: 1
-SpacesInAngles: false
-SpacesInContainerLiterals: true
-SpacesInCStyleCastParentheses: false
-SpacesInParentheses: false
-SpacesInSquareBrackets: false
+
+# Use modern C++. Argument stands for C++11, C++14, etc. 
 Standard: Cpp11
-TabWidth: 8
-UseTab: Never
 ...
-