Add mix-format function to format Elixir 1.6 files.

Author: anildigital

mix-format.el

@@ -0,0 +1,78 @@
+;;; mix-format.el --- Emacs plugin to mix format Elixir files
+
+;; Copyright (C) 2017 Anil Wadghule
+
+;; Author: Anil Wadghule <[email protected]>
+;; URL: https://github.com/anildigital/mix-format
+
+;; This file is NOT part of GNU Emacs.
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;;; Commentary:
+
+;; The mix-format function formats the elixir files with Elixir's `mix format`
+;; command
+
+;; e.g.
+;;
+;; (require 'mix-format)
+;; M-x mix-format
+;;
+
+;;; Code
+(defun mix-format (&optional is-interactive)
+  (interactive "p")
+
+  (unwind-protect
+      (let* (
+             (in-file (make-temp-file "mix-format"))
+             (out-file (make-temp-file "mix-format"))
+             (err-file (make-temp-file "mix-format"))
+             (contents (buffer-substring-no-properties (point-min) (point-max)))
+             (_ (with-temp-file in-file (insert contents))))
+
+
+        (let* ((command "mix")
+               (error-buffer (get-buffer-create "*mix-format errors*"))
+               (retcode (with-temp-buffer
+                          (call-process command
+                                        nil (list out-file err-file)
+                                        nil
+                                        "format"
+                                        "--print"
+                                        in-file))))
+
+          (with-current-buffer error-buffer
+            (read-only-mode 0)
+            (insert-file-contents err-file nil nil nil t)
+            (ansi-color-apply-on-region (point-min) (point-max))
+            (special-mode))
+
+          (if (zerop retcode )
+              (let ((p (point)))
+                (save-excursion
+                  (erase-buffer)
+                  (insert-buffer-substring out-file)
+                  (message "mix format applied"))
+                (goto-char p))
+
+            (if is-interactive
+                (display-buffer error-buffer)
+              (message "mix-format failed: see %s" (buffer-name error-buffer)))
+            ))
+        (delete-file in-file)
+        (delete-file err-file)
+        (delete-file out-file))))
+
+(provide 'mix-format)
+
+;;; mix-format.el ends here