CODEWITHSUNDEEP
c++11emacs
Philipp Claßen
Philipp Claßen

Reputation: 43970

Emacs indentation support for C++11 syntax?

Now that C++11 is out, I wondered if there are any tips on improving indentation support in Emacs when more and more code is migrated from C++98 to C++11.

Examples:

Here are some questionable indentions that I find myself working around:

struct m {
    int a;
    char b;
};

std::vector<m> foo { {1, 'a'},
        {2, 'b'},
            { 3, 'c'},
                { 4, 'd' }};

I'd prefer

std::vector<m> foo { {1, 'a'},
                     {2, 'b'},
                     { 3, 'c'},
                     { 4, 'd' }};

or even

std::vector<m> foo { {1, 'a'},
        {2, 'b'},
        { 3, 'c'},
        { 4, 'd' }};

for example.

Next one:

cout << 5
     << [](int a) {
    return 2 * a;
} (5);

I'd prefer

cout << 5
     << [](int a) {
            return 2 * a;
        } (5);

so that the block is indented relative to the lambda.

I find myself spending more time on indentation, which is annoying.

Are any packages or customizations that help to indent modern C++11 code?

(side note: I set up clang-format for Emacs, but I cannot get 100% compatibility which existing code and it also does not yet understand C++11 syntax very well. Still it is useful sometimes and sounds like a good idea for new projects.)

Upvotes: 20

Views: 1901

Answers (3)

mindriot
mindriot

Reputation: 5668

I just manually installed the latest CC Mode 5.33 from SourceForge, which should cover most of what you are looking for:

C++11 should now be fully supported, along with some features of C++14:

  • Uniform initialisation
  • Lambda functions
  • Parameter packs
  • Raw strings
  • Separators in integer literals
  • ">>" as a double template ender
  • etc.

Here are the indentations I get for your examples:

struct m {
  int a;
  char b;
};

std::vector<m> foo { {1, 'a'},
                     {2, 'b'},
                     { 3, 'c'},
                     { 4, 'd' }};

and

cout << 5
     << [](int a) {
          return 2 * a;
        } (5);

I also recommend installing modern-c++-font-lock (e.g. via MELPA) as suggested in this SO answer.

Upvotes: 3

user4268862
user4268862

Reputation:

Have a look at ClangFormat:

ClangFormat describes a set of tools that are built on top of LibFormat. It can support your workflow in a variety of ways including a standalone tool and editor integrations.

It is integrated in emacs:

(load "<path-to-clang>/tools/clang-format/clang-format.el")
(global-set-key [C-M-tab] 'clang-format-region)

You have many options to define your indent style for C++11 and beyond.

Clang-Format Style Options describes configurable formatting style options supported by LibFormat and ClangFormat.

Few examples:

  • AlignTrailingComments
  • AlwaysBreakTemplateDeclarations
  • etc.

Upvotes: 1

tobe
tobe

Reputation: 1741

When I'm using emacs, the following setting is good enough for me to indent code:

; auto indent   
(setq-default indent-tabs-mode nil)
(setq-default tab-width 2)

(define-key global-map (kbd "RET") 'newline-and-indent)
(defun indent-buffer ()
  (interactive)
  (save-excursion
    (indent-region (point-min) (point-max) nil)))
(global-set-key [f12] 'indent-buffer)

Hope it helps.

Upvotes: -3

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