emacs: Introduce number-format-mode.el

2 files changed, 137 insertions, 0 deletions

diff --git a/.config/emacs/modules/mm-editing.el b/.config/emacs/modules/mm-editing.el
index 2bc71e5..c6c8532 100644
--- a/.config/emacs/modules/mm-editing.el
+++ b/.config/emacs/modules/mm-editing.el
@@ -310,6 +310,14 @@ is as described by `emmet-expand-line'."
   (emmet-self-closing-tag-style ""))
 
 
+;;; Number Formatting
+
+(use-package number-format-mode
+  :commands ( number-format-buffer number-format-region
+              number-unformat-buffer number-unformat-region
+              number-format-mode))
+
+
 ;;; Additional Major Modes
 
 (use-package awk-ts-mode :ensure t)
diff --git a/.config/emacs/site-lisp/number-format-mode.el b/.config/emacs/site-lisp/number-format-mode.el
new file mode 100644
index 0000000..cbc5937
--- /dev/null
+++ b/.config/emacs/site-lisp/number-format-mode.el
@@ -0,0 +1,129 @@
+;;; number-format-mode.el --- Format numbers in the current buffer  -*- lexical-binding: t; -*-
+
+(eval-when-compile
+  (require 'cl-macs)
+  (require 'seq))
+
+(defgroup number-format nil
+  "Customization group for `number-format'."
+  :group 'convenience)                  ; TODO: Is this the right group?
+
+(defcustom number-format-separator "."
+  "Thousands separator to use in numeric literals."
+  :type 'string
+  :package-version '(number-format-mode . "1.0.0")
+  :group 'number-format)
+
+(defcustom number-format-predicate nil
+  "Function determining if a number should be formatted.
+When formatting a number, this function is called with the START and END
+range of the number in the buffer.  If this function returns non-nil the
+number is formatted.
+
+If this function is nil then all numbers are formatted."
+  :type 'function
+  :package-version '(number-format-mode . "1.0.0")
+  :group 'number-format)
+
+(defvar-local number-format--overlays (make-hash-table :test 'eq))
+(defconst number-format--regexp "\\b[0-9]\\{4,\\}\\b")
+
+(defun number-format--add-separators (s)
+  (while (string-match "\\(.*[0-9]\\)\\([0-9][0-9][0-9].*\\)" s)
+    (setq s (concat (match-string 1 s)
+                    number-format-separator
+                    (match-string 2 s))))
+  s)
+
+(defun number-format--adjust-overlays (ov _1 beg end &optional _2)
+  (let* ((ov-beg (overlay-start ov))
+         (ov-end (overlay-end   ov))
+         (overlays (overlays-in ov-beg ov-end)))
+    (mapcar #'delete-overlay (gethash ov number-format--overlays))
+    (save-excursion
+      (goto-char ov-beg)
+      (if (looking-at number-format--regexp :inhibit-modify)
+          (puthash ov (number-format--at-range ov-beg ov-end)
+                   number-format--overlays)
+        (delete-overlay ov)
+        (remhash ov number-format--overlays)))))
+
+(defun number-format--at-range (beg end)
+  (when (or (null number-format-predicate)
+            (funcall number-format-predicate beg end))
+    (let* ((offsets [3 1 2])
+           (len (- end beg))
+           (off (aref offsets (mod len 3))))
+      (goto-char (+ beg off)))
+    (let (overlays)
+      (while (< (point) end)
+        (let* ((group-end (+ (point) 3))
+               (ov (make-overlay (point) group-end)))
+          (overlay-put ov 'before-string ".")
+          (overlay-put ov 'evaporate t)
+          (push ov overlays)
+          (goto-char group-end)))
+      overlays)))
+
+(defun number-format--jit-lock (beg end)
+  (let ((line-beg (save-excursion (goto-char beg) (line-beginning-position)))
+	(line-end (save-excursion (goto-char end) (line-end-position))))
+    (number-unformat-region line-beg line-end)
+    (number-format-region   line-beg line-end)))
+
+;;;###autoload
+(defun number-format-region (beg end)
+  "Format numbers between BEG and END.
+When called interactively, format numbers in the active region."
+  (interactive "r")
+  (save-excursion
+    (goto-char beg)
+    (save-restriction
+      (narrow-to-region beg end)
+      (number-unformat-region beg end)
+      (while (re-search-forward number-format--regexp nil :noerror)
+        (save-excursion
+          (cl-destructuring-bind (beg end) (match-data)
+            (let ((ov (make-overlay beg end nil nil :rear-advance)))
+              (overlay-put ov 'evaporate t)
+              (dolist (sym '(insert-behind-hooks
+                             insert-in-front-hooks
+                             modification-hooks))
+                (overlay-put ov sym '(number-format--adjust-overlays)))
+              (puthash ov (number-format--at-range beg end)
+                       number-format--overlays))))))))
+
+;;;###autoload
+(defun number-unformat-region (beg end)
+  "Unformat numbers between BEG and END.
+When called interactively, unformat numbers in the active region."
+  (interactive "r")
+  (dolist (ov (overlays-in beg end))
+    (when-let ((overlays (gethash ov number-format--overlays)))
+      (mapcar #'delete-overlay overlays)
+      (remhash ov number-format--overlays)
+      (delete-overlay ov))))
+
+;;;###autoload
+(defun number-format-buffer ()
+  "Format numbers in the current buffer."
+  (interactive)
+  (number-format-region (point-min) (point-max)))
+
+;;;###autoload
+(defun number-unformat-buffer ()
+  "Unformat numbers in the current buffer."
+  (interactive)
+  (number-unformat-region (point-min) (point-max)))
+
+;;;###autoload
+(define-minor-mode number-format-mode
+  "TODO"
+  :lighter " Number-Format"
+  :group 'number-format
+  (number-unformat-buffer)
+  (if number-format-mode
+      (jit-lock-register #'number-format--jit-lock)
+    (jit-lock-unregister #'number-format--jit-lock)))
+
+(provide 'number-format)
\ No newline at end of file