[PATCH] D50078: clang-format: support aligned nested conditionals formatting

[Krasimir Georgiev via Phabricator via cfe-commits]

krasimir added a comment.

I'm happy with this patch!

We found a couple of rough edges:

- alignment after `?:` and
- new formatting of `_ ? _ ? _ : _ : _` patterns is bad

These are illustrated as examples D and E below (A, B and C look good to me). `test.cc` is how I'd expect clang-format to behave with this patch with `BreakBeforeTernaryOperators = true`, like in LLVM style.

- alignment after `?:`: this is a GNU extension and we've seen it used in C++ and ObjC: https://stackoverflow.com/questions/24538096/in-objective-c. I think this is special enough for us to consider an occurrence of `?:` to break a ternary operator chain for the purposes of this alignment. I'd expect a +4 alignment of the last 2 lines of example D for consistency with A.

- new formatting doesn't work for `_ ? _ ? _ : _ : _` patterns; old formatting is better in that case. I think the new chained alignment works very well for _ ? _ : _ ? _ : _ ... cases, but we should attempt it otherwise.



  % cat test.cc
  //-- column 80 ----------------------------------------------------------------V
  // A
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 
              ? bbbbbbbbbbbbbbbbbbb
              : cccccccccccccccccccc;
   
  //-- column 80 ----------------------------------------------------------------V
  // B
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaa ? bbbbbbbbbbbbbbbbbbb
          : cccccccccccccccccccc     ? dddddddddddddddddddd
                                     : eeeeeeeeeeeeeeeee;
   
  //-- column 80 ----------------------------------------------------------------V
  // C
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaa
              ?: bbbbbbbbbbbbbbbbbbb ? ccccccccccccc
                                     : ddddddddd;
   
  //-- column 80 ----------------------------------------------------------------V
  // D
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaa
              ?: bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
                     ? bbbbbbbbbbbbbbbbbbb
                     : cccccccccccccccccccc;
   
  //-- column 80 ----------------------------------------------------------------V
  // E 
  return temp[0] > temp[1] ? temp[0] > temp[2] ? 0 : 2
                           : temp[1] > temp[2] ? 1 : 2;



  % bin/clang-format -style=llvm test.cc
  //-- column 80 ----------------------------------------------------------------V
  // A
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
              ? bbbbbbbbbbbbbbbbbbb
              : cccccccccccccccccccc;
   
  //-- column 80 ----------------------------------------------------------------V
  // B
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaa ? bbbbbbbbbbbbbbbbbbb
          : cccccccccccccccccccc     ? dddddddddddddddddddd
                                     : eeeeeeeeeeeeeeeee;
   
  //-- column 80 ----------------------------------------------------------------V
  // C
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaa
              ?: bbbbbbbbbbbbbbbbbbb ? ccccccccccccc
                                     : ddddddddd;
   
  //-- column 80 ----------------------------------------------------------------V
  // D
  int i = aaaaaaaaaaaaaaaaaaaaaaaaaa
              ?: bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
                 ? bbbbbbbbbbbbbbbbbbb
                 : cccccccccccccccccccc;
   
  //-- column 80 ----------------------------------------------------------------V
  // E
  return temp[0] > temp[1]   ? temp[0] > temp[2] ? 0 : 2
         : temp[1] > temp[2] ? 1
                             : 2;


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D50078/new/

https://reviews.llvm.org/D50078