Diff regions in Emacs
But it's kind of too generic. I only want to view the different lines of two regions as quickly as possible.
So here is my code,
;; Diff two regions ;; Step 1: Select a region and `M-x diff-region-tag-selected-as-a' ;; Step 2: Select another region and `M-x diff-region-compare-with-b' ;; Press "q" in evil-mode or "C-c C-c" to exit the diff output buffer (defun diff-region-format-region-boundary (b e) "Make sure lines are selected and B is less than E" (let (tmp rlt) ;; swap b e, make sure b < e (when (> b e) (setq tmp b) (setq b e) (set e tmp)) ;; select lines (save-excursion ;; Another workaround for evil-visual-line bug: ;; In evil-mode, if we use hotkey V or `M-x evil-visual-line` to select line, ;; the (line-beginning-position) of the line which is after the last selected ;; line is always (region-end)! Don't know why. (if (and (> e b) (save-excursion (goto-char e) (= e (line-beginning-position))) (boundp 'evil-state) (eq evil-state 'visual)) (setq e (1- e))) (goto-char b) (setq b (line-beginning-position)) (goto-char e) (setq e (line-end-position))) (setq rlt (list b e)) rlt)) (defun diff-region-exit () (interactive) (bury-buffer "*Diff-region-output*") (winner-undo)) (defun diff-region-tag-selected-as-a () "Select a region to compare" (interactive) (when (region-active-p) (let (tmp buf) ;; select lines (setq tmp (diff-region-format-region-boundary (region-beginning) (region-end))) (setq buf (get-buffer-create "*Diff-regionA*")) (save-current-buffer (set-buffer buf) (erase-buffer)) (append-to-buffer buf (car tmp) (cadr tmp)))) (message "Now select other region to compare and run `diff-region-compare-with-b`")) (defun diff-region-compare-with-b () "Compare current region with region selected by `diff-region-tag-selected-as-a' " (interactive) (if (region-active-p) (let (rlt-buf diff-output (fa (make-temp-file (expand-file-name "scor" (or small-temporary-file-directory temporary-file-directory)))) (fb (make-temp-file (expand-file-name "scor" (or small-temporary-file-directory temporary-file-directory))))) ;; save current content as file B (when fb (setq tmp (diff-region-format-region-boundary (region-beginning) (region-end))) (write-region (car tmp) (cadr tmp) fb)) (setq rlt-buf (get-buffer-create "*Diff-region-output*")) (when (and fa (file-exists-p fa) fb (file-exists-p fb)) ;; save region A as file A (save-current-buffer (set-buffer (get-buffer-create "*Diff-regionA*")) (write-region (point-min) (point-max) fa)) ;; diff NOW! (setq diff-output (shell-command-to-string (format "diff -Nabur %s %s" fa fb))) ;; show the diff output (if (string= diff-output "") ;; two regions are same (message "Two regions are SAME!") ;; show the diff (save-current-buffer (switch-to-buffer-other-window rlt-buf) (set-buffer rlt-buf) (erase-buffer) (insert diff-output) (diff-mode) (if (fboundp 'evil-local-set-key) (evil-local-set-key 'normal "q" 'diff-region-exit)) (local-set-key (kbd "C-c C-c") 'diff-region-exit) ))) ;; clean the temporary files (if (and fa (file-exists-p fa)) (delete-file fa)) (if (and fb (file-exists-p fb)) (delete-file fb))) (message "Please select region at first!")))