Early attempts to format in GNU style.

[alexfh]

Summary

This still misses a few important features, so there's no mention of
this style in the help message, but a few style rules are implemented.

[alexfh]

Use getLLVMStyle() in getGoogleStyle() to reduce code duplication and make differences more clear.

include/clang/Format/Format.h

enum LanguageStandard {
     /// Automatic detection based on the input.
     LS_Auto
   };
 
   /// \brief Format compatible with this standard, e.g. use
   /// <tt>A<A<int> ></tt> instead of \c A<A<int>> for LS_Cpp03.
   LanguageStandard Standard;
 
+  /// \brief When \c true, blocks (including braces) get an additional level of
+  /// indentation.
+  bool IndentBlocks;
+
   /// \brief Indent case labels one level from the switch statement.
   ///
   /// When \c false, use the same indentation level as for the switch statement.
   /// Switch statement body is always indented one level more than case labels.
   bool IndentCaseLabels;
 
   /// \brief Different ways to indent namespace contents.
   enum NamespaceIndentationKind {
return AccessModifierOffset == R.AccessModifierOffset &&
            BreakConstructorInitializersBeforeComma ==
                R.BreakConstructorInitializersBeforeComma &&
            ColumnLimit == R.ColumnLimit &&
            ConstructorInitializerAllOnOneLineOrOnePerLine ==
                R.ConstructorInitializerAllOnOneLineOrOnePerLine &&
            DerivePointerBinding == R.DerivePointerBinding &&
            ExperimentalAutoDetectBinPacking ==
                R.ExperimentalAutoDetectBinPacking &&
+           IndentBlocks == R.IndentBlocks &&
            IndentCaseLabels == R.IndentCaseLabels &&
            IndentFunctionDeclarationAfterType ==
                R.IndentFunctionDeclarationAfterType &&
            IndentWidth == R.IndentWidth && Language == R.Language &&
            MaxEmptyLinesToKeep == R.MaxEmptyLinesToKeep &&
            NamespaceIndentation == R.NamespaceIndentation &&
            ObjCSpaceBeforeProtocolList == R.ObjCSpaceBeforeProtocolList &&
            PenaltyBreakComment == R.PenaltyBreakComment &&

 /// \brief Returns a format style complying with Mozilla's style guide:
 /// https://developer.mozilla.org/en-US/docs/Developer_Guide/Coding_Style.
 FormatStyle getMozillaStyle();
 
 /// \brief Returns a format style complying with Webkit's style guide:
 /// http://www.webkit.org/coding/coding-style.html
 FormatStyle getWebKitStyle();
 
+/// \brief Returns a format style complying with GNU Coding Standards:
+/// http://www.gnu.org/prep/standards/standards.html
+FormatStyle getGNUStyle();
+
 /// \brief Gets a predefined style for the specified language by name.
 ///
 /// Currently supported names: LLVM, Google, Chromium, Mozilla. Names are
 /// compared case-insensitively.
 ///
 /// Returns \c true if the Style has been set.
 bool getPredefinedStyle(StringRef Name, FormatStyle::LanguageKind Language,
                         FormatStyle *Style);

lib/Format/Format.cpp

 
 template <> struct MappingTraits<FormatStyle> {
   static void mapping(IO &IO, FormatStyle &Style) {
     // When reading, read the language first, we need it for getPredefinedStyle.
     IO.mapOptional("Language", Style.Language);
 
     if (IO.outputting()) {
       StringRef StylesArray[] = { "LLVM",    "Google", "Chromium",
-                                  "Mozilla", "WebKit" };
+                                  "Mozilla", "WebKit", "GNU" };
       ArrayRef<StringRef> Styles(StylesArray);
       for (size_t i = 0, e = Styles.size(); i < e; ++i) {
         StringRef StyleName(Styles[i]);
         FormatStyle PredefinedStyle;
         if (getPredefinedStyle(StyleName, Style.Language, &PredefinedStyle) &&
             Style == PredefinedStyle) {
           IO.mapOptional("# BasedOnStyle", StyleName);
           break;
template <> struct DocumentListTraits<std::vector<FormatStyle> > {
   }
 };
 }
 }
 
 namespace clang {
 namespace format {
 
-void setDefaultPenalties(FormatStyle &Style) {
-  Style.PenaltyBreakComment = 60;
-  Style.PenaltyBreakFirstLessLess = 120;
-  Style.PenaltyBreakString = 1000;
-  Style.PenaltyExcessCharacter = 1000000;
-}
-
 FormatStyle getLLVMStyle() {
   FormatStyle LLVMStyle;
   LLVMStyle.Language = FormatStyle::LK_Cpp;
   LLVMStyle.AccessModifierOffset = -2;
   LLVMStyle.AlignEscapedNewlinesLeft = false;
   LLVMStyle.AlignTrailingComments = true;
   LLVMStyle.AllowAllParametersOfDeclarationOnNextLine = true;
   LLVMStyle.AllowShortFunctionsOnASingleLine = true;
   LLVMStyle.AllowShortIfStatementsOnASingleLine = false;
   LLVMStyle.AllowShortLoopsOnASingleLine = false;
   LLVMStyle.AlwaysBreakBeforeMultilineStrings = false;
   LLVMStyle.AlwaysBreakTemplateDeclarations = false;
   LLVMStyle.BinPackParameters = true;
   LLVMStyle.BreakBeforeBinaryOperators = false;
   LLVMStyle.BreakBeforeTernaryOperators = true;
   LLVMStyle.BreakBeforeBraces = FormatStyle::BS_Attach;
   LLVMStyle.BreakConstructorInitializersBeforeComma = false;
   LLVMStyle.ColumnLimit = 80;
   LLVMStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = false;
   LLVMStyle.ConstructorInitializerIndentWidth = 4;
   LLVMStyle.Cpp11BracedListStyle = false;
   LLVMStyle.DerivePointerBinding = false;
   LLVMStyle.ExperimentalAutoDetectBinPacking = false;
+  LLVMStyle.IndentBlocks = false;
   LLVMStyle.IndentCaseLabels = false;
   LLVMStyle.IndentFunctionDeclarationAfterType = false;
   LLVMStyle.IndentWidth = 2;
   LLVMStyle.TabWidth = 8;
   LLVMStyle.MaxEmptyLinesToKeep = 1;
   LLVMStyle.NamespaceIndentation = FormatStyle::NI_None;
   LLVMStyle.ObjCSpaceBeforeProtocolList = true;
   LLVMStyle.PointerBindsToType = false;
   LLVMStyle.SpacesBeforeTrailingComments = 1;
   LLVMStyle.Standard = FormatStyle::LS_Cpp03;
   LLVMStyle.UseTab = FormatStyle::UT_Never;
   LLVMStyle.SpacesInParentheses = false;
   LLVMStyle.SpaceInEmptyParentheses = false;
   LLVMStyle.SpacesInCStyleCastParentheses = false;
   LLVMStyle.SpaceBeforeParens = FormatStyle::SBPO_ControlStatements;
   LLVMStyle.SpaceBeforeAssignmentOperators = true;
   LLVMStyle.ContinuationIndentWidth = 4;
   LLVMStyle.SpacesInAngles = false;
 
-  setDefaultPenalties(LLVMStyle);
+  LLVMStyle.PenaltyBreakComment = 60;
+  LLVMStyle.PenaltyBreakFirstLessLess = 120;
+  LLVMStyle.PenaltyBreakString = 1000;
+  LLVMStyle.PenaltyExcessCharacter = 1000000;
   LLVMStyle.PenaltyReturnTypeOnItsOwnLine = 60;
   LLVMStyle.PenaltyBreakBeforeFirstCallParameter = 19;
 
   return LLVMStyle;
 }
 
 FormatStyle getGoogleStyle() {
-  FormatStyle GoogleStyle;
-  GoogleStyle.Language = FormatStyle::LK_Cpp;
+  FormatStyle GoogleStyle = getLLVMStyle();
   GoogleStyle.AccessModifierOffset = -1;
   GoogleStyle.AlignEscapedNewlinesLeft = true;
-  GoogleStyle.AlignTrailingComments = true;
-  GoogleStyle.AllowAllParametersOfDeclarationOnNextLine = true;
-  GoogleStyle.AllowShortFunctionsOnASingleLine = true;
   GoogleStyle.AllowShortIfStatementsOnASingleLine = true;
   GoogleStyle.AllowShortLoopsOnASingleLine = true;
   GoogleStyle.AlwaysBreakBeforeMultilineStrings = true;
   GoogleStyle.AlwaysBreakTemplateDeclarations = true;
-  GoogleStyle.BinPackParameters = true;
-  GoogleStyle.BreakBeforeBinaryOperators = false;
-  GoogleStyle.BreakBeforeTernaryOperators = true;
-  GoogleStyle.BreakBeforeBraces = FormatStyle::BS_Attach;
-  GoogleStyle.BreakConstructorInitializersBeforeComma = false;
-  GoogleStyle.ColumnLimit = 80;
   GoogleStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = true;
-  GoogleStyle.ConstructorInitializerIndentWidth = 4;
   GoogleStyle.Cpp11BracedListStyle = true;
   GoogleStyle.DerivePointerBinding = true;
-  GoogleStyle.ExperimentalAutoDetectBinPacking = false;
   GoogleStyle.IndentCaseLabels = true;
   GoogleStyle.IndentFunctionDeclarationAfterType = true;
-  GoogleStyle.IndentWidth = 2;
-  GoogleStyle.TabWidth = 8;
-  GoogleStyle.MaxEmptyLinesToKeep = 1;
-  GoogleStyle.NamespaceIndentation = FormatStyle::NI_None;
   GoogleStyle.ObjCSpaceBeforeProtocolList = false;
   GoogleStyle.PointerBindsToType = true;
   GoogleStyle.SpacesBeforeTrailingComments = 2;
   GoogleStyle.Standard = FormatStyle::LS_Auto;
-  GoogleStyle.UseTab = FormatStyle::UT_Never;
-  GoogleStyle.SpacesInParentheses = false;
-  GoogleStyle.SpaceInEmptyParentheses = false;
-  GoogleStyle.SpacesInCStyleCastParentheses = false;
-  GoogleStyle.SpaceBeforeParens = FormatStyle::SBPO_ControlStatements;
-  GoogleStyle.SpaceBeforeAssignmentOperators = true;
-  GoogleStyle.ContinuationIndentWidth = 4;
-  GoogleStyle.SpacesInAngles = false;
 
-  setDefaultPenalties(GoogleStyle);
   GoogleStyle.PenaltyReturnTypeOnItsOwnLine = 200;
   GoogleStyle.PenaltyBreakBeforeFirstCallParameter = 1;
 
   return GoogleStyle;
 }
 
 FormatStyle getGoogleJSStyle() {
   FormatStyle GoogleJSStyle = getGoogleStyle();
FormatStyle getWebKitStyle() {
   Style.BreakConstructorInitializersBeforeComma = true;
   Style.ColumnLimit = 0;
   Style.IndentWidth = 4;
   Style.NamespaceIndentation = FormatStyle::NI_Inner;
   Style.PointerBindsToType = true;
   return Style;
 }
 
+FormatStyle getGNUStyle() {
+  FormatStyle Style = getLLVMStyle();
+  Style.BreakBeforeBinaryOperators = true;
+  Style.BreakBeforeBraces = FormatStyle::BS_Allman;
+  Style.BreakBeforeTernaryOperators = true;
+  Style.ColumnLimit = 79;
+  Style.IndentBlocks = true;
+  Style.SpaceBeforeParens = FormatStyle::SBPO_Always;
+  return Style;
+}
+
 bool getPredefinedStyle(StringRef Name, FormatStyle::LanguageKind Language,
                         FormatStyle *Style) {
   if (Name.equals_lower("llvm")) {
     *Style = getLLVMStyle();
   } else if (Name.equals_lower("chromium")) {
     *Style = getChromiumStyle();
   } else if (Name.equals_lower("mozilla")) {
     *Style = getMozillaStyle();
   } else if (Name.equals_lower("google")) {
     *Style = Language == FormatStyle::LK_JavaScript ? getGoogleJSStyle()
                                                     : getGoogleStyle();
   } else if (Name.equals_lower("webkit")) {
     *Style = getWebKitStyle();
+  } else if (Name.equals_lower("gnu")) {
+    *Style = getGNUStyle();
   } else {
     return false;
   }
 
   Style->Language = Language;
   return true;
 }
 

unittests/Format/FormatTest.cpp

TEST_F(FormatTest, GetsPredefinedStyleByName) {
   EXPECT_TRUE(getPredefinedStyle("moZILla", FormatStyle::LK_Cpp, &Styles[2]));
   EXPECT_ALL_STYLES_EQUAL(Styles);
 
   Styles[0] = getWebKitStyle();
   EXPECT_TRUE(getPredefinedStyle("WebKit", FormatStyle::LK_Cpp, &Styles[1]));
   EXPECT_TRUE(getPredefinedStyle("wEbKit", FormatStyle::LK_Cpp, &Styles[2]));
   EXPECT_ALL_STYLES_EQUAL(Styles);
 
+  Styles[0] = getGNUStyle();
+  EXPECT_TRUE(getPredefinedStyle("GNU", FormatStyle::LK_Cpp, &Styles[1]));
+  EXPECT_TRUE(getPredefinedStyle("gnU", FormatStyle::LK_Cpp, &Styles[2]));
+  EXPECT_ALL_STYLES_EQUAL(Styles);
+
   EXPECT_FALSE(getPredefinedStyle("qwerty", FormatStyle::LK_Cpp, &Styles[0]));
 }
 
 TEST_F(FormatTest, GetsCorrectBasedOnStyle) {
   SmallVector<FormatStyle, 8> Styles;
   Styles.resize(2);
 
   Styles[0] = getGoogleStyle();