How can I align function parameter names in clang-format?

Question

Is it possible to use clang-format to format struct members and function parameter names into columns?

For example:

struct
{
   int           alpha; //aligned to 'b' of "beta"
   unsigned int  beta;
   MyObject     *gamma; //aligned with 'g' not '*'
};

void foobar (int           alpha, //aligned to 'b' of "beta"
             unsigned int  beta
             MyObject     *gamma) //aligned with 'g' not '*'
{
}

If it's not possible, could I extend clang-format somehow to achieve this?

Answer 1

clang-format recently (3.7 or 3.8) gained some more options to adjust alignment, what I was asking in my question is still not fully supported, but we can now get a little closer:

AlignConsecutiveDeclarations: true

which aligns declarations like shown above.

Unfortunately there still seems to be limited control for formatting of the pointer asterisk, see clang-format: Align asterisk (*) of pointer declaration with variable name

Answer 2

Well, you can get close.

For function declarations:

You can set BinPackParameters=false, which will force that all the parameters of a function declaration are either on one line or each on a different line, and they will be aligned as you show.

(But not with tab stops in between types and identifiers. That is not possible in clang format right now afaik.)

Also, see the option AllowAllParametersOfDeclarationOnNextLine

Allow putting all parameters of a function declaration onto the next line even if BinPackParameters is false.

For structs, I don't think you can achieve this.

Having written patches for clang-format myself in the past, I think it would be a lot of work to get the alignment like you are suggesting. You would have to write a fair bit of C++ yourself into clang lib format to support this.

Answer 3

Following up on your post, I'm able to get the following:

struct
{
  int          alpha;
  unsigned int beta;
  MyObject *   gamma;
};

void foobar( int          alphaXXXXXXXXXX,
             unsigned int betaXXXXXXXXX,
             MyObject *   gammaXXXXXXXX )
{
}

with BinPackArguments and BinPackParameters both false, and AlignConsecutiveAssignments and AlignConsecutiveDeclarations both set to true (documentation of these parameters). I had to extend the length of the variables to the function, because the original could fit all of them on one line.