1 files changed, 75 insertions, 0 deletions
diff --git a/lisp/fmt/fmt.el b/lisp/fmt/fmt.el
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+++ b/lisp/fmt/fmt.el
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+;;; fmt.el ---                                       -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2023  John Turner
+
+;; Author: John Turner <notroot@gentoo-pc>
+
+;; 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 3 of the License, 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.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+(defgroup fmt nil
+  "Format buffers using external programs such as rustfmt.")
+
+(defcustom fmt-executable nil
+  "Formatter executable to use for formatting a buffer."
+  :local t
+  :type '(string)
+  :group 'fmt)
+
+(defcustom fmt-args nil
+  "Args to use when running fmt-executable."
+  :local t
+  :type '(repeat string)
+  :group 'fmt)
+
+(defcustom fmt-stdout-buffer "*fmt stdout*"
+  "Buffer to send fmt-executable stdout to."
+  :type '(string)
+  :group 'fmt)
+
+(defcustom fmt-stderr-file "/dev/null"
+  "Buffer to send fmt-executable stderr to."
+  :type '(string)
+  :group 'fmt)
+
+(defcustom fmt-before-format-hook nil
+  "Hooks to run before fmt-executable runs."
+  :type '(hook)
+  :group 'fmt)
+
+(define-error 'fmt-failure "fmt-failure")
+
+(defun fmt-buffer ()
+  (run-hooks 'fmt-before-format-hook)
+  (let ((exit-status (apply 'call-process-region `(,(point-min) ,(point-max) ,fmt-executable
+                                                   nil ,(list fmt-stdout-buffer fmt-stderr-file)
+                                                   nil ,@fmt-args))))
+    (if (zerop exit-status)
+        (replace-buffer-contents fmt-stdout-buffer)
+      (signal 'fmt-failure nil))))
+
+(defun fmt-current-buffer ()
+  (interactive)
+  (condition-case _ (fmt-buffer)
+    ('fmt-failure (message "%s failed, see %s for more details" fmt-executable fmt-stderr-file))))
+
+;; hooks
+
+(defun fmt-erase-stdout-buffer ()
+  (with-current-buffer (get-buffer-create fmt-stdout-buffer)
+    (erase-buffer)))
+
+(add-hook 'fmt-before-format-hook 'fmt-erase-stdout-buffer)
+
+(provide 'fmt)
+;;; fmt.el ends here