💥 Rewrite line numbers system for Emacs 25

This removes the various doom-line-number* variables and replaces it
with the Emacs 26 display-line-numbers API, which I've ported to Emacs
25.x (however, it uses nlinum under the hood, and not all of
display-line-numbers options are supported).

core/autoload/line-numbers.el

@@ -0,0 +1,82 @@
+;;; core/autoload/line-numbers.el -*- lexical-binding: t; -*-
+;;;###if (not (boundp 'display-line-numbers))
+
+;; This was lifted out of the display-line-numbers library in Emacs 26.1 and
+;; modified to use nlinum for Emacs 25.x users. It should be removed should
+;; Emacs 25 support be removed.
+
+;;;###autoload
+(defvar display-line-numbers t
+  "Non-nil means display line numbers.
+
+If the value is t, display the absolute number of each line of a buffer
+shown in a window.  Absolute line numbers count from the beginning of
+the current narrowing, or from buffer beginning.  If the value is
+relative, display for each line not containing the window's point its
+relative number instead, i.e. the number of the line relative to the
+line showing the window's point.
+
+In either case, line numbers are displayed at the beginning of each
+non-continuation line that displays buffer text, i.e. after each newline
+character that comes from the buffer.  The value visual is like
+relative but counts screen lines instead of buffer lines.  In practice
+this means that continuation lines count as well when calculating the
+relative number of a line.
+
+Lisp programs can disable display of a line number of a particular
+buffer line by putting the display-line-numbers-disable text property
+or overlay property on the first visible character of that line.")
+
+;;;###autoload
+(defcustom display-line-numbers-type t
+  "The default type of line numbers to use in `display-line-numbers-mode'.
+See `display-line-numbers' for value options."
+  :type '(choice (const :tag "Relative line numbers" relative)
+                 (const :tag "Relative visual line numbers" visual)
+                 (other :tag "Absolute line numbers" t)))
+
+;;;###autoload
+(defcustom display-line-numbers-grow-only nil
+  "If non-nil, do not shrink line number width."
+  :type 'boolean)
+
+;;;###autoload
+(defcustom display-line-numbers-width-start nil
+  "If non-nil, count number of lines to use for line number width.
+When `display-line-numbers-mode' is turned on,
+`display-line-numbers-width' is set to the minimum width necessary
+to display all line numbers in the buffer."
+  :type 'boolean)
+
+(defun display-line-numbers-update-width ()
+  "Prevent the line number width from shrinking."
+  (let ((width (line-number-display-width)))
+    (when (> width (or display-line-numbers-width 1))
+      (setq display-line-numbers-width width))))
+
+;;;###autoload
+(define-minor-mode display-line-numbers-mode
+  "Toggle display of line numbers in the buffer.
+This uses `display-line-numbers' internally.
+
+To change the type of line numbers displayed by default,
+customize `display-line-numbers-type'.  To change the type while
+the mode is on, set `display-line-numbers' directly."
+  :lighter nil
+  (cond ((eq display-line-numbers-type 'relative)
+         (if display-line-numbers-mode
+             (nlinum-relative-off)
+           (nlinum-relative-on)))
+        ((not (null display-line-numbers-type))
+         (nlinum-mode (if display-line-numbers-mode +1 -1)))))
+
+(defun display-line-numbers--turn-on ()
+  "Turn on `display-line-numbers-mode'."
+  (unless (or (minibufferp)
+              ;; taken from linum.el
+              (and (daemonp) (null (frame-parameter nil 'client))))
+    (display-line-numbers-mode)))
+
+;;;###autoload
+(define-globalized-minor-mode global-display-line-numbers-mode
+  display-line-numbers-mode display-line-numbers--turn-on)

core/core-ui.el

@@ -296,43 +296,11 @@ from the default."
 ;; Line numbers
 ;;
 
-(defvar doom-line-numbers-style t
+;; Emacs 26+ has native line number support, and will ignore nlinum. This is for
-  "The default styles to use for the line number display. Accepts one of the
+;; Emacs 25 users:
-following:
+(defun doom|enable-line-numbers ()  (display-line-numbers-mode +1))
+(defun doom|disable-line-numbers () (display-line-numbers-mode -1))
 
-  nil         No line numbers
-  t           Ordinary line numbers
-  'relative   Relative line numbers
-
-Use `doom/toggle-line-numbers' to cycle between these line number styles.")
-
-(when (boundp 'display-line-numbers)
-  (defvar doom-line-numbers-visual-style nil
-    "If non-nil, relative line numbers will be countered by screen line, rather
-than buffer line. Setting this to non-nil is the equivalent of using 'visual in
-`display-line-numbers'.
-
-It has no effect on nlinum."))
-
-(defun doom|enable-line-numbers (&optional arg)
-  "Enables the display of line numbers, using `display-line-numbers' (in Emacs
-26+) or `nlinum-mode'.
-
-See `doom-line-numbers-style' to control the style of line numbers to display."
-  (cond ((boundp 'display-line-numbers)
-         (setq display-line-numbers (unless (eq arg -1) doom-line-numbers-style)))
-        ((eq doom-line-numbers-style 'relative)
-         (if (eq arg -1)
-             (nlinum-relative-off)
-           (nlinum-relative-on)))
-        ((not (null doom-line-numbers-style))
-         (nlinum-mode (or arg +1)))))
-
-(defun doom|disable-line-numbers ()
-  "Disable the display of line numbers."
-  (doom|enable-line-numbers -1))
-
-;; Emacs 26+ has native line number support.
 ;; Line number column. A faster (or equivalent, in the worst case) line number
 ;; plugin than `linum-mode'.
 (def-package! nlinum
@@ -484,7 +452,7 @@ frame's window-system, the theme will be reloaded.")
 ;; a good indicator that Emacs isn't frozen
 (add-hook 'doom-init-ui-hook #'blink-cursor-mode)
 ;; line numbers in most modes
-(add-hook! (prog-mode text-mode conf-mode) #'doom|enable-line-numbers)
+(add-hook! (prog-mode text-mode conf-mode) #'display-line-numbers-mode)
 
 ;; More sensibile replacements for default commands
 (define-key! 'global

modules/app/write/config.el

@@ -7,9 +7,7 @@
   "What to set `line-spacing' in `+write-mode'.")
 
 (defun +write|init-line-numbers ()
-  (if +write-mode
+  (display-line-numbers-mode (if +write-mode +1 -1)))
-      (doom|enable-line-numbers)
-    (doom|disable-line-numbers)))
 
 (defun +write|init-mixed-pitch ()
   (mixed-pitch-mode (if +write-mode +1 -1)))

modules/lang/ess/config.el

@@ -34,7 +34,7 @@
   (unless (featurep! :lang julia)
     (add-to-list 'auto-mode-alist '("\\.jl\\'" . ess-julia-mode)))
   :config
-  (add-hook 'ess-mode-hook #'doom|enable-line-numbers)
+  (add-hook 'ess-mode-hook #'display-line-numbers-mode)
   (setq ess-offset-continued 'straight
         ess-expression-offset 2
         ess-nuke-trailing-whitespace-p t

modules/lang/rest/config.el

@@ -6,7 +6,7 @@
   (set-popup-rule! "^\\*HTTP Response" :size 0.4 :quit 'other)
 
   ;; line numbers aren't enabled by default in fundamental-mode-derived modes
-  (add-hook 'restclient-mode-hook #'doom|enable-line-numbers)
+  (add-hook 'restclient-mode-hook #'display-line-numbers-mode)
 
   ;; Forces underlying SSL verification to prompt for self-signed or invalid
   ;; certs, rather than silently reject them.