[clang-format] Add BeforeWhileInDoWhile BraceWrapping option

[ebaker355]

Summary

Adds a new BraceWrapping option called BeforeWhileInDoWhile.

Code like this:

do {
    // Some code
} while (1);

becomes:

do {
    // Some code
}
while (1);

This is meant to compliment the BreakBeforeElse wrapping option.

I couldn't think of a better name for the option than BeforeWhileInDoWhile. I'm open to suggestions!

Also, this is my first attempt at submitting a patch for this project. If I've done anything wrong, please let me know. Thanks!

[ebaker355]

Remove unintended blank line change.

[ebaker355]

Ping. Anyone have an opinion on this?

[djasper]

Is there a coding style that actually recommends this? I would be quite doubtful that it is a good idea as it makes those loops harder to distinguish from other while loops. Generally, there is a certain bar to getting additional style flags into clang-format:
http://clang.llvm.org/docs/ClangFormatStyleOptions.html#adding-additional-style-options

[ebaker355]

Thanks for responding, and for the documentation link! It is certainly wise to not attempt "to supporting every single style used by a codebase somewhere in the wild."

I do not know of a predefined coding style that recommends this format. My thinking was:

• it complements the "else on new line" option
• I have seen other code formatters that offer this style option

[ebaker355]

Since I cannot meet these criteria:

• be used in a project of significant size (have dozens of contributors)
• have a publicly accessible style guide

I will abandon this revision request. Thank you for considering!

[djasper]

Feel free to leave this patch around. Maybe somebody else comes up with something that meets the other criteria ;-).

Me personally, I just think that seeing "while (1);" on a single line is quite misleading. But maybe that is just me.

[ebaker355]

Ok, cool! :) Thanks!

Yeah, personally, I like seeing the vertical alignment of the keywords, especially in code editors that draw indentation lines.

[MyDeveloperDay]

This change need unit tests

docs/ClangFormatStyleOptions.rst

   * ``bool AfterUnion`` Wrap union definitions.
   * ``bool BeforeCatch`` Wrap before ``catch``.
   * ``bool BeforeElse`` Wrap before ``else``.
+  * ``bool BeforeWhileInDoWhile`` Wrap before ``while`` in do...while.
   * ``bool IndentBraces`` Indent the wrapped braces themselves.
 
 

include/clang/Format/Format.h

     bool BeforeCatch;
     /// \brief Wrap before \c else.
     bool BeforeElse;
+    /// \brief Wrap before \c while in do...while.
+    bool BeforeWhileInDoWhile;
     /// \brief Indent the wrapped braces themselves.
     bool IndentBraces;
   };

lib/Format/Format.cpp

     IO.mapOptional("AfterUnion", Wrapping.AfterUnion);
     IO.mapOptional("BeforeCatch", Wrapping.BeforeCatch);
     IO.mapOptional("BeforeElse", Wrapping.BeforeElse);
+    IO.mapOptional("BeforeWhileInDoWhile", Wrapping.BeforeWhileInDoWhile);
     IO.mapOptional("IndentBraces", Wrapping.IndentBraces);
   }
 };

     return Style;
   FormatStyle Expanded = Style;
   Expanded.BraceWrapping = {false, false, false, false, false, false,
-                            false, false, false, false, false};
+                            false, false, false, false, false, false};
   switch (Style.BreakBeforeBraces) {
   case FormatStyle::BS_Linux:
     Expanded.BraceWrapping.AfterClass = true;

     break;
   case FormatStyle::BS_GNU:
     Expanded.BraceWrapping = {true, true, true, true, true, true,
-                              true, true, true, true, true};
+                              true, true, true, true, true, true};
     break;
   case FormatStyle::BS_WebKit:
     Expanded.BraceWrapping.AfterFunction = true;

   LLVMStyle.BreakBeforeTernaryOperators = true;
   LLVMStyle.BreakBeforeBraces = FormatStyle::BS_Attach;
   LLVMStyle.BraceWrapping = {false, false, false, false, false, false,
-                             false, false, false, false, false};
+                             false, false, false, false, false, false};
   LLVMStyle.BreakConstructorInitializersBeforeComma = false;
   LLVMStyle.BreakAfterJavaFieldAnnotations = false;
   LLVMStyle.ColumnLimit = 80;

lib/Format/UnwrappedLineParser.cpp

     parseStructuralElement();
     --Line->Level;
   }
-
+  if (FormatTok->Tok.is(tok::kw_while) &&
+      Style.BraceWrapping.BeforeWhileInDoWhile) {
+    addUnwrappedLine();
+  }
   // FIXME: Add error handling.
   if (!FormatTok->Tok.is(tok::kw_while)) {
     addUnwrappedLine();

unittests/Format/FormatTest.cpp

   CHECK_PARSE_NESTED_BOOL(BraceWrapping, AfterUnion);
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, BeforeCatch);
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, BeforeElse);
+  CHECK_PARSE_NESTED_BOOL(BraceWrapping, BeforeWhileInDoWhile);
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, IndentBraces);
 }