.dir-locals.el

((nil . ((sentence-end-double-space . t)
         (eval . (add-to-list 'auto-mode-alist '("\\.h\\'" . c++-mode)))))
 (python-mode . ((fill-column . 79)
                 (python-fill-docstring-style . django)))
 (c-mode . ((eval . (setq flycheck-gcc-include-path (list "/usr/include/python3.7")))))
 (c++-mode . ((c-basic-offset . 4)
              (fill-column . 90)
              (flycheck-gcc-language-standard . "gnu++17")
              (eval . (progn
                        (c-set-offset 'innamespace 0)

                        (defun do-shell (s)
                          ;; Helper for running a shell command and getting the first line
                          ;; of its output.
                          (substring (shell-command-to-string s) 0 -1))

                        (setq flycheck-gcc-include-path
                              (let* ((python-include
                                      (do-shell "python -c \"import sysconfig; print(sysconfig.get_path('include'))\""))
                                     (project-root
                                      (do-shell "git rev-parse --show-toplevel")))
                                 (list python-include project-root))))))))