Re: tabulated-list sort icon is reversed

[Philippe Vaucher <philippe.vaucher@gmail.com>]

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On Fri, Aug 10, 2018 at 4:52 PM Yuri Khan <yurivkhan@gmail.com> wrote:

> On Fri, Aug 10, 2018 at 9:15 PM Philippe Vaucher
> <philippe.vaucher@gmail.com> wrote:
>
> > To be honest I'm losing a bit of steam here, I now suspect this patch
> will never land because the ACSII part is unsolvable, and because I guess
> that using an image requires quite a lot of refactoring (displaying an
> inline image instead of a character is likely to be complicated).
>
> Fortunately there’s an easy escape hatch from this problem: Make it a
> defcustom. Then we can spend an inordinate amount of time bikeshedding
> the default.
>

Good idea! Here's a patch in that direction, here are things that I'm not
sure about:

   - variable name? `tabulated-list-sort-ascending-indicator`?
   `tabulated-list-sort-ascending-icon`? For ASCII, `-ascii` or `-glyphless`?
   - group definition: does tabulated-list belong to another group?
   - 4 defcustoms or 2? For example, it could be `(defcustom
   tabulated-list-sort-ascending-texts '(" ▼" "v"))`, that way you customize
   both icons at the same time (it could even be only one defcustom with :asc
   keywords etc)

Thanks,
Philippe

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From 0b3264ecddc5b23b00055387e8cd9c5c4d9da766 Mon Sep 17 00:00:00 2001
From: Philippe Vaucher <philippe.vaucher@gmail.com>
Date: Fri, 10 Aug 2018 21:59:24 +0200
Subject: [PATCH] Allow customization of sort indicators in tabulated-list

* lisp/emacs-lisp/tabulated-list.el: add customization group, add
  defcustoms.
---
 lisp/emacs-lisp/tabulated-list.el | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/lisp/emacs-lisp/tabulated-list.el b/lisp/emacs-lisp/tabulated-list.el
index 58619ecda0..4552ef7f98 100644
--- a/lisp/emacs-lisp/tabulated-list.el
+++ b/lisp/emacs-lisp/tabulated-list.el
@@ -36,6 +36,29 @@
 
 ;;; Code:
 
+(defgroup tabulated-list nil
+  "Tabulated-list customization group.")
+
+(defcustom tabulated-list-sort-ascending-icon " ▼"
+  "Icon to display when sort order is ascending."
+  :group 'tabulated-list
+  :type 'string)
+
+(defcustom tabulated-list-sort-descending-icon " ▲"
+  "Icon to display when sort order is descending."
+  :group 'tabulated-list
+  :type 'string)
+
+(defcustom tabulated-list-sort-ascending-glyphless "v"
+  "Glyphless icon to display when sort order is ascending."
+  :group 'tabulated-list
+  :type 'string)
+
+(defcustom tabulated-list-sort-descending-glyphless "^"
+  "Glyphless icon to display when sort order is descending."
+  :group 'tabulated-list
+  :type 'string)
+
 ;; The reason `tabulated-list-format' and other variables are
 ;; permanent-local is to make it convenient to switch to a different
 ;; major mode, switch back, and have the original Tabulated List data
@@ -176,8 +199,8 @@ If ADVANCE is non-nil, move forward by one line afterwards."
   (let ((table (make-char-table 'glyphless-char-display nil)))
     (set-char-table-parent table glyphless-char-display)
     ;; Some text terminals can't display the Unicode arrows; be safe.
-    (aset table 9650 (cons nil "^"))
-    (aset table 9660 (cons nil "v"))
+    (aset table 9650 (cons nil tabulated-list-sort-descending-glyphless))
+    (aset table 9660 (cons nil tabulated-list-sort-ascending-glyphless))
     table)
   "The `glyphless-char-display' table in Tabulated List buffers.")
 
@@ -229,8 +252,8 @@ Populated by `tabulated-list-init-header'.")
 		  (concat label
 			  (cond
 			   ((> (+ 2 (length label)) width) "")
-			   ((cdr tabulated-list-sort-key) " ▲")
-			   (t " ▼")))
+			   ((cdr tabulated-list-sort-key) tabulated-list-sort-descending-icon)
+			   (t tabulated-list-sort-ascending-icon)))
 		  'face 'bold
 		  'tabulated-list-column-name label
 		  button-props))
-- 
2.18.0