[elpa] externals/lin d51e895b46 28/46: Upgrade to version 0.2.0

[ELPA Syncer]

branch: externals/lin
commit d51e895b46116eeb4120ec909f61d2d092efad47
Author: Protesilaos Stavrou <info@protesilaos.com>
Commit: Protesilaos Stavrou <info@protesilaos.com>

    Upgrade to version 0.2.0
---
 CHANGELOG.org |  67 ++++++++++++
 README.org    | 231 ++++++++++++++--------------------------
 lin.el        | 334 ++++++++++++++++++++++++++++++++++++++++++++--------------
 3 files changed, 404 insertions(+), 228 deletions(-)

diff --git a/CHANGELOG.org b/CHANGELOG.org
new file mode 100644
index 0000000000..c43b888640
--- /dev/null
+++ b/CHANGELOG.org
@@ -0,0 +1,67 @@
+#+TITLE: Change log of lin.el
+#+AUTHOR: Protesilaos Stavrou
+#+EMAIL: info@protesilaos.com
+#+OPTIONS: ':nil toc:nil num:nil author:nil email:nil
+
+This document contains the release notes for each tagged commit on the
+project's main git repository: <https://gitlab.com/protesilaos/lin>.
+
+The newest release is at the top.  For further details, please consult
+the manual: <https://protesilaos.com/emacs/lin>.
+
+* Version 0.2.0 on 2022-03-16
+
+Rewrote the entirety of =lin.el= to make the configuration easier and
+keep the code streamlined.  The gist is that now Lin automatically
+enables ~hl-line-mode~ in every mode implied by ~lin-mode-hooks~.  Here
+is how Lin should be set up henceforth:
+
+#+begin_src emacs-lisp
+(require 'lin)
+
+(setq lin-face 'lin-blue) ; check doc string for alternative styles
+
+(lin-setup) ; Either run this or change `lin-mode-hooks'
+
+(customize-set-variable
+ 'lin-mode-hooks ; do not use `setq' with this; `customize-set-variable' runs 
`lin-setup' automatically
+ '(dired-mode-hook
+   elfeed-search-mode-hook
+   git-rebase-mode-hook
+   ibuffer-mode-hook
+   ilist-mode-hook
+   ledger-report-mode-hook
+   log-view-mode-hook
+   magit-log-mode-hook
+   mu4e-headers-mode
+   notmuch-search-mode-hook
+   notmuch-tree-mode-hook
+   occur-mode-hook
+   org-agenda-mode-hook
+   tabulated-list-mode-hook))
+#+end_src
+
+The manual has been updated to reflect those changes:
+<https://protesilaos.com/emacs/lin>.
+
+Thanks to:
+
++ Christian Tietze for showing how the Lin face can use colors from the
+  macOS palette.  The original contribution was in merge request 2:
+  <https://gitlab.com/protesilaos/lin/-/merge_requests/2>.  Now we
+  provide the ~lin-mac~ and ~lin-mac-override-fg~ faces.  These can be
+  assigned as a value to the user option ~lin-face~.
+
++ Damien Cassou for suggesting that Lin sets itself up for a list of
+  mode hooks.  The original contribution was in merge request 3:
+  <https://gitlab.com/protesilaos/lin/-/merge_requests/3>.  It has now
+  been rewritten as the ~lin-mode-hooks~ user option, though the idea is
+  the same.
+
++ Federico Stilman for adding ~mu4e-headers-mode~ to the list that
+  Damien had provided and which now lives as ~lin-mode-hooks~.
+  Federico's contribution was sent as a patch via email.
+
+* Version 0.1.0 on 2022-03-14
+
+Initial release of the package.  Please read the manual.
diff --git a/README.org b/README.org
index bc4fb08f52..d2de39703b 100644
--- a/README.org
+++ b/README.org
@@ -5,9 +5,9 @@
 #+options: ':t toc:nil author:t email:t num:t
 #+startup: content
 
-#+macro: stable-version 0.1.0
-#+macro: release-date 2021-11-01
-#+macro: development-version 0.2.0-dev
+#+macro: stable-version 0.2.0
+#+macro: release-date 2022-03-18
+#+macro: development-version 0.3.0-dev
 #+macro: file @@texinfo:@file{@@$1@@texinfo:}@@
 #+macro: space @@texinfo:@: @@
 #+macro: kbd @@texinfo:@kbd{@@$1@@texinfo:}@@
@@ -17,7 +17,7 @@
 #+texinfo_filename: lin.info
 #+texinfo_dir_category: Emacs misc features
 #+texinfo_dir_title: LIN Is Noticeable: (lin)
-#+texinfo_dir_desc: Buffer-local remapping of hl-line face
+#+texinfo_dir_desc: Make 'hl-line-mode' more suitable for selection UIs
 #+texinfo_header: @set MAINTAINERSITE @uref{https://protesilaos.com,maintainer 
webpage}
 #+texinfo_header: @set MAINTAINER Protesilaos Stavrou
 #+texinfo_header: @set MAINTAINEREMAIL @email{info@protesilaos.com}
@@ -43,7 +43,7 @@ Current development target is {{{development-version}}}.
 :CUSTOM_ID: h:33b423a6-1b89-40a3-bbbc-1524138be3a4
 :END:
 
-Copyright (C) 2021  Free Software Foundation, Inc.
+Copyright (C) 2021-2022  Free Software Foundation, Inc.
 
 #+begin_quote
 Permission is granted to copy, distribute and/or modify this document
@@ -63,29 +63,63 @@ modify this GNU manual.”
 :END:
 #+cindex: Overview
 
-LIN locally remaps the ~hl-line~ face to a style that is optimal for major
-modes where line selection is the primary mode of interaction.
-
-The idea is that ~hl-line~ cannot work equally well for contexts with
-competing priorities: (i) line selection, or (ii) simple line highlight.
-In the former case, the current line needs to be made prominent because
-it carries a specific meaning of some significance in the given context.
-Whereas in the latter case, the primary mode of interaction does not
-revolve around the line highlight itself: it may be because the focus is
-on editing text or reading through the buffer's contents, so the current
-line highlight is more of a gentle reminder of the point's location on
-the vertical axis.
-
-~lin-mode~ only shows its effect when ~hl-line-mode~ is active or, more
-specifically, when the ~hl-line~ face is used in the buffer.  ~lin-mode~
-DOES NOT activate ~hl-line-mode~ and does not do anything other than the
-aforementioned face remapping.
+Lin is a stylistic enhancement for Emacs' built-in ~hl-line-mode~.  It
+remaps the ~hl-line~ face (or equivalent) buffer-locally to a style that
+is optimal for major modes where line selection is the primary mode of
+interaction.
+
+The idea is that ~hl-line-mode~ cannot work equally well for contexts
+with competing priorities: (i) line selection, or (ii) simple line
+highlight.  In the former case, the current line needs to be made
+prominent because it carries a specific meaning of some significance in
+the given context: the user has to select a line.  Whereas in the latter
+case, the primary mode of interaction does not revolve around the line
+highlight itself: it may be because the focus is on editing text or
+reading through the buffer's contents, so the current line highlight is
+more of a reminder of the point's location on the vertical axis.
+
+#+findex: lin-mode
+#+vindex: lin-mode-hooks
+#+findex: lin-setup
+~lin-mode~ enables ~hl-line-mode~ by adding it to every hook specified
+in the user option ~lin-mode-hooks~.  Users are advised to configure
+that variable with ~customize-set-variable~, or the Custom UI, or
+equivalent as it has a function which automatically sets up Lin.  Those
+who prefer to set values with ~setq~ must handle the process manually,
+by using the ~lin-setup~ function.
+
+#+vindex: lin-face
+#+vindex: lin-blue
+#+vindex: lin-red
+#+vindex: lin-green
+#+vindex: lin-yellow
+#+vindex: lin-blue
+#+vindex: lin-magenta
+#+vindex: lin-cyan
+#+vindex: lin-mac
+#+vindex: lin-red-override-fg
+#+vindex: lin-green-override-fg
+#+vindex: lin-yellow-override-fg
+#+vindex: lin-blue-override-fg
+#+vindex: lin-magenta-override-fg
+#+vindex: lin-cyan-override-fg
+#+vindex: lin-mac-override-fg
+Users can selected their preferred style by customizing the user option
+~lin-face~.  Options include the faces ~lin-red~, ~lin-green~,
+~lin-yellow~, ~lin-blue~ (default), ~lin-magenta~, ~lin-cyan~,
+~lin-mac~, ~lin-red-override-fg~, ~lin-green-override-fg~,
+~lin-yellow-override-fg~, ~lin-blue-override-fg~,
+~lin-magenta-override-fg~, ~lin-cyan-override-fg~,
+~lin-mac-override-fg~, or any other face that preferably has a
+background attribute.  The Lin faces with the =-override-fg= suffix set
+a foreground value which replaces that of the underlying text.  Whereas
+the others only specify a background attribute.
 
 * Installation
 :PROPERTIES:
 :CUSTOM_ID: h:7b68abd3-a854-4b72-b704-05ca013dfa7f
 :END:
-#+cindex: Installation
+#+cindex: Install Lin
 
 LIN is not in any package archive for the time being, though I plan to
 submit it to GNU ELPA (as such, any non-trivial patches require
@@ -118,140 +152,35 @@ Finally, in your =init.el= (or equivalent) evaluate this:
 
 Everything is in place to set up the package.
 
-* Sample usage
+* Sample configuration
 :PROPERTIES:
 :CUSTOM_ID: h:7d63e6a9-5a49-4106-970c-ae8bdb06ae9d
 :END:
-#+cindex: Sample configuration
-
-#+begin_src emacs-lisp
-(require 'lin)
-(add-hook 'elfeed-search-mode-hook #'lin-mode)
-#+end_src
-
-To activate ~lin-mode~ on all modes where it makes sense:
+#+cindex: Set up Lin
 
 #+begin_src emacs-lisp
 (require 'lin)
-(lin-add-to-many-modes)
-#+end_src
-
-The customization option ~lin-foreign-hooks~ lets you configure the
-list of hooks affected by ~lin-add-to-many-modes~.
-
-Else invoke ~lin-mode~ interactively.
-
-#+vindex: lin-override-foreground
-In terms of customization options, ~lin-foreground-override~ determines
-whether LIN should also override the foreground colors on the current
-line.  By default, it refrains from doing so.
-
-* Customize LIN faces
-:PROPERTIES:
-:CUSTOM_ID: h:4598ee11-bd6d-4ed4-baca-883b896ac3d6
-:END:
-
-#+vindex: lin-hl
-#+vindex: lin-hl-override-fg
-The two faces that LIN defines are ~lin-hl~ and ~lin-hl-override-fg~.  The
-latter is used only when ~lin-override-foreground~ is non-nil.
-
-To change the attributes of a face, one can use ~set-face-attribute~.  In
-these examples, we change the background color to a shade of magenta
-that is suitable for light themes and we also apply a colored underline:
-
-#+begin_src emacs-lisp
-;; This changes the face that is meant NOT to override the foregrounds.
-;; Check `lin-override-foreground'.
-(set-face-attribute 'lin-hl nil :background "#f0d3ff" :underline "#e0a3ff")
-
-;; And this one is the face that DOES override the foregrounds
-(set-face-attribute 'lin-hl-override-fg nil :background "#f0d3ff" :underline 
"#e0a3ff")
-#+end_src
 
-When using [[https://protesilaos.com/emacs/modus-themes][the Modus themes]] 
(built-in to Emacs version 28 or higher), it
-is possible to retrieve values directly from the active theme's palette.
-And, it is possible to have different values for either =modus-operandi=
-(the light theme) or =modus-vivendi= (dark).  Here we showcase the former
-method which involves the function ~modus-themes-color~ (read its doc
-string for the technicalities and/or consult the themes' manual for more
-advanced customizations, such as to make the changes adapt to theme
-switching between Modus Operandi and Vivendi):
-
-#+begin_src emacs-lisp
-(set-face-attribute 'lin-hl nil
-                    :background (modus-themes-color 'green-subtle-bg)
-                    :underline (modus-themes-color 'green-intense))
-#+end_src
-
-** Use system colors on macOS
-:PROPERTIES:
-:CUSTOM_ID: h:6bb11a50-cca9-49ca-9ea0-9d26c9324068
-:END:
-
-On macOS, it is possible to use named system colors. For a list of
-available colors, see 
[[https://developer.apple.com/design/human-interface-guidelines/macos/visual-design/color/][Apple's
 Human Interface Guidelines]].
-
-To use macOS's named colors for selections as LIN's background and
-foreground instead of specifying color values directly, tweak the two
-LIN faces:
-
-#+begin_src emacs-lisp
-(when (memq window-system '(mac ns))
-  (set-face-attribute 'lin-hl nil
-                      :background "selectedContentBackgroundColor")
-
-  ;; To also override the foreground (see `lin-override-foreground'):
-  (set-face-attribute 'lin-hl-override-fg nil
-                      :foreground "alternateSelectedControlTextColor"
-                      :background "selectedContentBackgroundColor"))
-#+end_src
-
-Note that these named colors are "Dynamic System Colors": in dark
-mode, they produce a different value than in light mode. That means
-you don't need to pick dark and light colors individually. The same
-color names will work.
-
-However, you need to trigger an update of LIN's faces to pick up the
-color values if you change the appearance from dark to light, or light
-to dark. macOS builds of Emacs have a hook for this, and you can
-perform a color update by adding a function to
-~ns-system-appearance-change-functions~:
-
-#+begin_src emacs-lisp
-(defun my-lin-macos-system-colors ()
-  (when (memq window-system '(mac ns))
-    (set-face-attribute 'lin-hl nil
-                        :background "selectedContentBackgroundColor")
-
-    ;; To also override the foreground (see `lin-override-foreground'):
-    (set-face-attribute 'lin-hl-override-fg nil
-                        :foreground "alternateSelectedControlTextColor"
-                        :background "selectedContentBackgroundColor")))
-
-(when (memq window-system '(mac ns))
-  (add-hook 'ns-system-appearance-change-functions 
#'my-lin-macos-system-colors))
-#+end_src
-
-If you want to use a different color than the macOS selection colors
-in dark mode, you can tweak this approach:
-
-#+begin_src emacs-lisp
-(defun my-lin--macos-mode-color (light dark)
-  "Use LIGHT or DARK color value, depending on macOS mode."
-  (if (eq ns-system-appearance 'light)
-      light
-    dark))
-
-(defun my-lin-custom-faces ()
-  (when (memq window-system '(mac ns))
-    (let ((bg (my-lin--macos-mode-color "selectedContentBackgroundColor" 
"#2a40b8"))
-          (fg (my-lin--macos-mode-color "alternateSelectedControlTextColor" 
"#ffffff")))
-      (set-face-attribute 'lin-hl nil :background bg)
-      (set-face-attribute 'lin-hl-override-fg nil :background bg :foreground 
fg))))
-
-(when (memq window-system '(mac ns))
-  (add-hook 'ns-system-appearance-change-functions #'my-lin-custom-faces))
+(setq lin-face 'lin-blue) ; check doc string for alternative styles
+
+(lin-setup) ; Either run this or change `lin-mode-hooks'
+
+(customize-set-variable
+ 'lin-mode-hooks ; do not use `setq' with this; `customize-set-variable' runs 
`lin-setup' automatically
+ '(dired-mode-hook
+   elfeed-search-mode-hook
+   git-rebase-mode-hook
+   ibuffer-mode-hook
+   ilist-mode-hook
+   ledger-report-mode-hook
+   log-view-mode-hook
+   magit-log-mode-hook
+   mu4e-headers-mode
+   notmuch-search-mode-hook
+   notmuch-tree-mode-hook
+   occur-mode-hook
+   org-agenda-mode-hook
+   tabulated-list-mode-hook))
 #+end_src
 
 * Acknowledgements
@@ -260,7 +189,7 @@ in dark mode, you can tweak this approach:
 :END:
 #+cindex: Contributors
 
-LIN is meant to be a collective effort.  Every bit of help matters.
+Lin is meant to be a collective effort.  Every bit of help matters.
 
 + Author/maintainer :: Protesilaos Stavrou.
 
diff --git a/lin.el b/lin.el
index 25f2992c99..83c4519d6b 100644
--- a/lin.el
+++ b/lin.el
@@ -1,11 +1,12 @@
-;;; lin.el --- LIN Is Noticeable -*- lexical-binding: t -*-
+;;; lin.el --- Make `hl-line-mode' more suitable for selection UIs -*- 
lexical-binding: t -*-
 
-;; Copyright (C) 2021  Free Software Foundation, Inc.
+;; Copyright (C) 2021-2022  Free Software Foundation, Inc.
 
 ;; Author: Protesilaos Stavrou <info@protesilaos.com>
 ;; URL: https://gitlab.com/protesilaos/lin
 ;; Version: 0.1.0
 ;; Package-Requires: ((emacs "27.1"))
+;; Keywords: convenience, faces, theme
 
 ;; This file is NOT part of GNU Emacs.
 
@@ -24,34 +25,63 @@
 
 ;;; Commentary:
 ;;
-;; LIN locally remaps the `hl-line' face to a style that is optimal for
-;; major modes where line selection is the primary mode of interaction.
+;; Lin is a stylistic enhancement for Emacs' built-in `hl-line-mode'.
+;; It remaps the `hl-line face (or equivalent) buffer-locally to a style
+;; that is optimal for major modes where line selection is the primary
+;; mode of interaction.
 ;;
-;; The idea is that `hl-line' cannot work equally well for contexts with
-;; competing priorities: (i) line selection, or (ii) simple line
+;; The idea is that `hl-line-mode' cannot work equally well for contexts
+;; with competing priorities: (i) line selection, or (ii) simple line
 ;; highlight.  In the former case, the current line needs to be made
-;; prominent because it carries a specific meaning of some significance
-;; in the given context.  Whereas in the latter case, the primary mode
-;; of interaction does not revolve around the line highlight itself: it
-;; may be because the focus is on editing text or reading through the
-;; buffer's contents, so the current line highlight is more of a gentle
-;; reminder of the point's location on the vertical axis.
+;; prominent because it carries a specific meaning of some significance in
+;; the given context: the user has to select a line.  Whereas in the latter
+;; case, the primary mode of interaction does not revolve around the line
+;; highlight itself: it may be because the focus is on editing text or
+;; reading through the buffer's contents, so the current line highlight is
+;; more of a reminder of the point's location on the vertical axis.
 ;;
-;; `lin-mode' only shows its effect when `hl-line-mode' is active or,
-;; more specifically, when the `hl-line' face is used in the buffer.
-;; `lin-mode' DOES NOT activate `hl-line-mode' and does not do anything
-;; other than the aforementioned face remapping.
+;; `lin-mode' enables `hl-line-mode' by adding it to every hook specified
+;; in the user option `lin-mode-hooks'.  Users are advised to configure
+;; that variable with `customize-set-variable', or the Custom UI, or
+;; equivalent as it has a function which automatically sets up Lin.  Those
+;; who prefer to set values with `setq' must handle the process manually,
+;; by using the `lin-setup' function.
 ;;
-;; Sample usage:
+;; Users can selected their preferred style by customizing the user
+;; option `lin-face'.  Options include the faces `lin-red', `lin-green',
+;; `lin-yellow', `lin-blue' (default), `lin-magenta', `lin-cyan',
+;; `lin-mac', `lin-red-override-fg', `lin-green-override-fg',
+;; `lin-yellow-override-fg', `lin-blue-override-fg',
+;; `lin-magenta-override-fg', `lin-cyan-override-fg',
+;; `lin-mac-override-fg', or any other face that preferably has a
+;; background attribute.  The Lin faces with the =-override-fg= suffix
+;; set a foreground value which replaces that of the underlying text.
+;; Whereas the others only specify a background attribute.
 ;;
-;;    (add-hook 'elfeed-search-mode-hook #'lin-mode)
+;; Sample configuration:
 ;;
-;; Or for more mode hooks:
+;;     (require 'lin)
 ;;
-;;    (dolist (hook '(elfeed-search-mode-hook notmuch-search-mode-hook))
-;;      (add-hook hook #'lin-mode))
+;;     (setq lin-face 'lin-blue)
 ;;
-;; Else invoke `lin-mode' interactively.
+;;     (lin-setup)
+;;
+;;     (customize-set-variable
+;;      'lin-mode-hooks
+;;      '(dired-mode-hook
+;;        elfeed-search-mode-hook
+;;        git-rebase-mode-hook
+;;        ibuffer-mode-hook
+;;        ilist-mode-hook
+;;        ledger-report-mode-hook
+;;        log-view-mode-hook
+;;        magit-log-mode-hook
+;;        mu4e-headers-mode
+;;        notmuch-search-mode-hook
+;;        notmuch-tree-mode-hook
+;;        occur-mode-hook
+;;        org-agenda-mode-hook
+;;        tabulated-list-mode-hook))
 ;;
 ;; Consult the manual for further details.  Or visit the documentation's
 ;; web page: <https://protesilaos.com/emacs/lin>.
@@ -59,106 +89,256 @@
 ;;; Code:
 
 (require 'face-remap)
+(require 'hl-line)
+
+(make-obsolete 'lin--default-foreign-hooks 'lin-mode-hooks "0.2.0")
+
+(defgroup lin ()
+  "Make `hl-line' appropriate for selection UIs."
+  :group 'convenience)
 
-(defconst lin--default-foreign-hooks
-  ;; please keep the list sorted:
-  '(elfeed-search-mode-hook
+(defcustom lin-mode-hooks
+  '(dired-mode-hook
+    elfeed-search-mode-hook
     git-rebase-mode-hook
     ibuffer-mode-hook
+    ilist-mode-hook
     ledger-report-mode-hook
     log-view-mode-hook
     magit-log-mode-hook
     mu4e-headers-mode
     notmuch-search-mode-hook
     notmuch-tree-mode-hook
+    occur-mode-hook
     org-agenda-mode-hook
-    ilist-mode-hook
     tabulated-list-mode-hook)
-  "List of default hooks in which to use `lin-mode'.
-See also the user option `lin-override-foreground'.")
+  "List of hooks that should enable `lin-mode'.
 
-(defgroup lin ()
-  "Locally remap `hl-line' face for greater flexility."
-  :group 'convenience)
+When Lin is set up, it activates `hl-line-mode' and remaps its
+face to `lin-face'.  This makes it possible to distinguish
+between the two use-cases of permanent line highlighting: (i)
+gentle reminder of where the point is while editing, (ii) current
+selection.
 
-(defcustom lin-override-foreground nil
-  "Do not override foreground colors.
+Set this user option with `customize-set-variable', the Custom
+UI, or equivalent.  It has a custom setter function which
+automatically sets things up when configured that way.  Users who
+prefer to use `setq' must run `lin-setup' manually.  Consult its
+doc string."
+  :type '(repeat variable)
+  :initialize #'custom-initialize-default
+  :set (lambda (symbol value)
+         (if (eq value (default-value symbol))
+             (set-default symbol value)
+           (lin-setup 'reverse)
+           (set-default symbol value)
+           (lin-setup)))
+  :group 'lin)
 
-Set to non-nil to always override the foreground colors on the
-current line that is highlighted by `lin-mode'.
+(defcustom lin-face 'lin-blue
+  "Face to use for the pulse line.
+Users can select one among `lin-red', `lin-green', `lin-yellow',
+`lin-blue' (default), `lin-magenta', `lin-cyan', `lin-mac',
+`lin-red-override-fg', `lin-green-override-fg',
+`lin-yellow-override-fg', `lin-blue-override-fg',
+`lin-magenta-override-fg', `lin-cyan-override-fg',
+`lin-mac-override-fg', or any other face that preferably has a
+background attribute."
+  :type '(radio (face :tag "Red style" lin-red)
+                (face :tag "Green style" lin-green)
+                (face :tag "Yellow style" lin-yellow)
+                (face :tag "Blue style (default)" lin-blue)
+                (face :tag "Magenta style" lin-magenta)
+                (face :tag "Cyan style" lin-cyan)
+                (face :tag "macOS style" lin-mac)
+                (face :tag "Red style that also overrides the underlying 
foreground" lin-red-override-fg)
+                (face :tag "Green style that also overrides the underlying 
foreground" lin-green-override-fg)
+                (face :tag "Yellow style that also overrides the underlying 
foreground" lin-yellow-override-fg)
+                (face :tag "Blue style that also overrides the underlying 
foreground" lin-blue-override-fg)
+                (face :tag "Magenta style that also overrides the underlying 
foreground" lin-magenta-override-fg)
+                (face :tag "Cyan style that also overrides the underlying 
foreground" lin-cyan-override-fg)
+                (face :tag "macOS style that also overrides the underlying 
foreground" lin-mac-override-fg)
+                (face :tag "Other face (must have a background)"))
+  :group 'lin)
 
-This requires `lin-mode' to be restarted wherever it is active.
+;;;; Faces
 
-When this option is nil, the `lin-hl' face is used.  Otherwise
-the `lin-hl-override-fg' is applied."
-  :type 'boolean
+(defgroup lin-faces ()
+  "Faces for `lin.el'."
   :group 'lin)
 
-(defcustom lin-foreign-hooks lin--default-foreign-hooks
-  "List of hook variable names in which to use `lin-mode'.
+(defface lin-red
+  '((default :foreground unspecified :underline nil :extend t)
+    (((class color) (min-colors 88) (background light))
+     :background "#ffd3d3")
+    (((class color) (min-colors 88) (background dark))
+     :background "#500f0f")
+    (t :background "red"))
+  "Alternative red face for `lin-face'."
+  :group 'lin-faces)
 
-Call `lin-add-to-many-modes' to start `lin-mode' for all these
-hooks."
-  :type '(repeat variable))
+(defface lin-red-override-fg
+  '((default :inherit lin-red)
+    (((background light))
+     :foreground "black")
+    (((background dark))
+     :foreground "white"))
+  "Like `lin-red' but also sets a foreground."
+  :group 'lin-faces)
 
-(defface lin-hl
+(defface lin-green
   '((default :foreground unspecified :underline nil :extend t)
     (((class color) (min-colors 88) (background light))
-     :background "#b0d8ff")
+     :background "#bfeabf")
     (((class color) (min-colors 88) (background dark))
-     :background "#103265")
-    (t :inherit highlight))
-  "Like `lin-hl-override-fg', but does not override foreground color.
-Used only when `lin-override-foreground' is nil."
-  :group 'lin)
+     :background "#0f300f")
+    (t :background "green"))
+  "Alternative green face for `lin-face'."
+  :group 'lin-faces)
+
+(defface lin-green-override-fg
+  '((default :inherit lin-green)
+    (((background light))
+     :foreground "black")
+    (((background dark))
+     :foreground "white"))
+  "Like `lin-green' but also sets a foreground."
+  :group 'lin-faces)
 
-(defface lin-hl-override-fg
-  '((default :underline nil :extend t)
+(defface lin-yellow
+  '((default :foreground unspecified :underline nil :extend t)
     (((class color) (min-colors 88) (background light))
-     :background "#b0d8ff" :foreground "#000000")
+     :background "#ffecaa")
     (((class color) (min-colors 88) (background dark))
-     :background "#103265" :foreground "#ffffff")
-    (t :inherit highlight))
-  "Face for locally remapped `hl-line' face via `lin-mode'.
-Used only when `lin-override-foreground' is non-nil."
-  :group 'lin)
+     :background "#412200")
+    (t :background "yellow"))
+  "Alternative yellow face for `lin-face'."
+  :group 'lin-faces)
+
+(defface lin-yellow-override-fg
+  '((default :inherit lin-yellow)
+    (((background light))
+     :foreground "black")
+    (((background dark))
+     :foreground "white"))
+  "Like `lin-yellow' but also sets a foreground."
+  :group 'lin-faces)
+
+(defface lin-blue
+  '((default :foreground unspecified :underline nil :extend t)
+    (((class color) (min-colors 88) (background light))
+     :background "#c0e4ff")
+    (((class color) (min-colors 88) (background dark))
+     :background "#002460")
+    (t :background "blue"))
+  "Alternative blue face for `lin-face'."
+  :group 'lin-faces)
+
+(defface lin-blue-override-fg
+  '((default :inherit lin-blue)
+    (((background light))
+     :foreground "black")
+    (((background dark))
+     :foreground "white"))
+  "Like `lin-blue' but also sets a foreground."
+  :group 'lin-faces)
+
+(defface lin-magenta
+  '((default :foreground unspecified :underline nil :extend t)
+    (((class color) (min-colors 88) (background light))
+     :background "#ffd9ff")
+    (((class color) (min-colors 88) (background dark))
+     :background "#401d40")
+    (t :background "magenta"))
+  "Alternative magenta face for `lin-face'."
+  :group 'lin-faces)
+
+(defface lin-magenta-override-fg
+  '((default :inherit lin-magenta)
+    (((background light))
+     :foreground "black")
+    (((background dark))
+     :foreground "white"))
+  "Like `lin-magenta' but also sets a foreground."
+  :group 'lin-faces)
+
+(defface lin-cyan
+  '((default :foreground unspecified :underline nil :extend t)
+    (((class color) (min-colors 88) (background light))
+     :background "#baeaf8")
+    (((class color) (min-colors 88) (background dark))
+     :background "#002f3f")
+    (t :background "cyan"))
+  "Alternative cyan face for `lin-face'."
+  :group 'lin-faces)
+
+(defface lin-cyan-override-fg
+  '((default :inherit lin-cyan)
+    (((background light))
+     :foreground "black")
+    (((background dark))
+     :foreground "white"))
+  "Like `lin-cyan' but also sets a foreground."
+  :group 'lin-faces)
+
+;; TODO 2022-03-18: Can we find all system styles?  Then we can rename
+;; this to `lin-system'.
+(defface lin-mac
+  '((((type ns))
+     ;; 
<https://developer.apple.com/design/human-interface-guidelines/macos/visual-design/color/>.
+     :background "selectedContentBackgroundColor" :extend t)
+    (t :inherit lin-blue))
+  "Alternative macOS-style face for `lin-face'."
+  :group 'lin-faces)
+
+(defface lin-mac-override-fg
+  '((t :inherit lin-mac :foreground "alternateSelectedControlTextColor"))
+  "Like `lin-mac' but also sets a foreground."
+  :group 'lin-faces)
+
+;;;; Lin setup
 
 (defvar-local lin--cookie nil
   "Cookie returned by `face-remap-add-relative'.")
 
-(defvar hl-line-face)
-
 (defun lin--source-face ()
   "Determine the source face, what to remap."
   (cond
    ((derived-mode-p 'mu4e-headers-mode)
     'mu4e-header-highlight-face)
+   ((derived-mode-p 'magit-mode)
+    'magit-section-highlight)
    ;; Do not target `hl-line' directly, as it can be changed by
    ;; `hl-line-face'.
    ((bound-and-true-p hl-line-face)
-      hl-line-face)
+    hl-line-face)
    (t
     'hl-line)))
 
-(defun lin--dest-face ()
-  "Determine the destination face, what source must remap to.
-This is controlled by `lin-override-foreground', which see."
-  (if lin-override-foreground 'lin-hl-override-fg 'lin-hl))
-
 (define-minor-mode lin-mode
-  "Remap `hl-line' face to a local LIN face.
-The overall style is controlled by `lin-override-foreground'."
+  "Enable `hl-line-mode' and remap its face to `lin-face'."
   :local t
   :init-value nil
   (if lin-mode
-      (setq lin--cookie
-            (face-remap-add-relative (lin--source-face) (lin--dest-face)))
-    (face-remap-remove-relative lin--cookie)))
-
-(defun lin-add-to-many-modes ()
-  "Turn on `lin-mode' on every mode of `lin-foreign-hooks'."
-  (dolist (hook lin-foreign-hooks)
-    (add-hook hook #'lin-mode)))
+      (progn
+        (setq lin--cookie
+              (face-remap-add-relative (lin--source-face) lin-face))
+        (hl-line-mode 1))
+    (face-remap-remove-relative lin--cookie)
+    (hl-line-mode -1)))
+
+(defun lin-setup (&optional reverse)
+  "Set up Lin for select mode hooks.
+
+This adds `lin-mode' and `hl-line-mode' to every hook in
+`lin-mode-hooks'.
+
+With optional non-nil REVERSE argument, remove those hooks."
+  (if reverse
+      (dolist (hook lin-mode-hooks)
+        (remove-hook hook #'lin-mode))
+    (dolist (hook lin-mode-hooks)
+      (add-hook hook #'lin-mode))))
 
 (provide 'lin)