bug#50038: Permanent shift-select-mode

bug#50038: Permanent shift-select-mode

[Juri Linkov]

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It's very convenient to use a shift-translated key to activate the region,
because e.g. 'S-C-f' requires typing less keys than 'C-SPC C-f'.

But when there is a need to extend the region by typing a navigation key
that is not shift-translated, it abruptly deactivates the region.
The current default behavior was implemented in such unusable way
because "other apps" behave the same way.

So the following patch provides an option for the behavior that is more
convenient than in "other apps":


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diff --git a/lisp/simple.el b/lisp/simple.el
index 25a5a166e8..d951570937 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -6649,9 +6649,15 @@ shift-select-mode
 by any subsequent point motion key that was not shift-translated, or
 by any action that normally deactivates the mark in Transient Mark mode.
 
+When the value is `permanent', the mark will not be deactivated
+by any subsequent point motion key that was not shift-translated.
+
 See `this-command-keys-shift-translated' for the meaning of
 shift-translation."
-  :type 'boolean
+  :type '(choice (const :tag "Off" nil)
+                 (const :tag "Permanent" permanent)
+                 (other :tag "On" t))
+  :version "28.1"
   :group 'editing-basics)
 
 (defun handle-shift-selection ()
@@ -6669,7 +6675,12 @@ handle-shift-selection
 Otherwise, if the region has been activated temporarily,
 deactivate it, and restore the variable `transient-mark-mode' to
 its earlier value."
-  (cond ((and shift-select-mode this-command-keys-shift-translated)
+  (cond ((and (eq shift-select-mode 'permanent)
+              this-command-keys-shift-translated)
+         (unless mark-active
+           (push-mark nil nil t)))
+        ((and shift-select-mode
+              this-command-keys-shift-translated)
          (unless (and mark-active
 		      (eq (car-safe transient-mark-mode) 'only))
 	   (setq-local transient-mark-mode

bug#50038: Permanent shift-select-mode

[Lars Ingebrigtsen]

Juri Linkov <juri@linkov.net> writes:

> So the following patch provides an option for the behavior that is more
> convenient than in "other apps":

Makes sense to me.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#50038: Permanent shift-select-mode

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Date: Fri, 13 Aug 2021 10:04:27 +0300
> 
> But when there is a need to extend the region by typing a navigation key
> that is not shift-translated, it abruptly deactivates the region.
> The current default behavior was implemented in such unusable way
> because "other apps" behave the same way.
> 
> So the following patch provides an option for the behavior that is more
> convenient than in "other apps":

Thanks.

> --- a/lisp/simple.el
> +++ b/lisp/simple.el
> @@ -6649,9 +6649,15 @@ shift-select-mode
>  by any subsequent point motion key that was not shift-translated, or
>  by any action that normally deactivates the mark in Transient Mark mode.
>  
> +When the value is `permanent', the mark will not be deactivated
> +by any subsequent point motion key that was not shift-translated.

This is a negative description, which tells half of the story, and
leaves it to the reader to guess the other half (how to deactivate the
mark in this case).  How about describing both, and in a positive way?
For example:

  When the value is `permanent', the mark will be deactivated by any
  action which normally does that, but not by motion keys that were
  not shift-translated.

And finally, a question: is it enough to have this as a user option?
That is, what if the user wants this only temporarily, for the next
sequence of commands that extend the region?  Should we perhaps have a
better solution for that use case?  More generally, perhaps this
feature is almost always wanted only for a sequence of commands, never
globally for extended periods of time?  In that case, a user option is
not the best solution; it is better to have some minor mode that could
be turned on and off with a simple key sequence.
>  See `this-command-keys-shift-translated' for the meaning of
>  shift-translation."
> -  :type 'boolean
> +  :type '(choice (const :tag "Off" nil)
> +                 (const :tag "Permanent" permanent)
> +                 (other :tag "On" t))
> +  :version "28.1"
>    :group 'editing-basics)

This would also need a NEWS entry, if we eventually decide to do it
this way.

bug#50038: Permanent shift-select-mode

[Juri Linkov]

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>> +When the value is `permanent', the mark will not be deactivated
>> +by any subsequent point motion key that was not shift-translated.
>
> This is a negative description, which tells half of the story, and
> leaves it to the reader to guess the other half (how to deactivate the
> mark in this case).  How about describing both, and in a positive way?
> For example:
>
>   When the value is `permanent', the mark will be deactivated by any
>   action which normally does that, but not by motion keys that were
>   not shift-translated.

Fixed in the new patch.

> And finally, a question: is it enough to have this as a user option?
> That is, what if the user wants this only temporarily, for the next
> sequence of commands that extend the region?  Should we perhaps have a
> better solution for that use case?  More generally, perhaps this
> feature is almost always wanted only for a sequence of commands, never
> globally for extended periods of time?  In that case, a user option is
> not the best solution; it is better to have some minor mode that could
> be turned on and off with a simple key sequence.

It would be very surprising if someone might want something more complicated.
But everyone is welcome to extend this feature when such a need will arise.

>>  See `this-command-keys-shift-translated' for the meaning of
>>  shift-translation."
>> -  :type 'boolean
>> +  :type '(choice (const :tag "Off" nil)
>> +                 (const :tag "Permanent" permanent)
>> +                 (other :tag "On" t))
>> +  :version "28.1"
>>    :group 'editing-basics)
>
> This would also need a NEWS entry, if we eventually decide to do it
> this way.

This patch also adds a NEWS entry:


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diff --git a/etc/NEWS b/etc/NEWS
index 09ace73f5d..37acef0be1 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -263,6 +263,12 @@ This works in text buffers and over images.  Typing a numeric prefix arg
 (e.g. 'M-5') before starting horizontal scrolling changes its step value.
 The value is saved in the user option 'mouse-wheel-scroll-amount-horizontal'.
 
+---
+** New choice 'permanent' for 'shift-select-mode'.
+When the mark was activated by shifted motion keys,
+non-shifted motion keys don't deactivate the mark
+after customizing 'shift-select-mode' to 'permanent'.
+
 ---
 ** The default value of 'frame-title-format' and 'icon-title-format' has changed.
 These variables are used to display the title bar of visible frames
diff --git a/lisp/simple.el b/lisp/simple.el
index 985beb06fc..960422a6b2 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -6649,9 +6649,16 @@ shift-select-mode
 by any subsequent point motion key that was not shift-translated, or
 by any action that normally deactivates the mark in Transient Mark mode.
 
+When the value is `permanent', the mark will be deactivated by any
+action which normally does that, but not by motion keys that were
+not shift-translated.
+
 See `this-command-keys-shift-translated' for the meaning of
 shift-translation."
-  :type 'boolean
+  :type '(choice (const :tag "Off" nil)
+                 (const :tag "Permanent" permanent)
+                 (other :tag "On" t))
+  :version "28.1"
   :group 'editing-basics)
 
 (defun handle-shift-selection ()
@@ -6669,7 +6676,12 @@ handle-shift-selection
 Otherwise, if the region has been activated temporarily,
 deactivate it, and restore the variable `transient-mark-mode' to
 its earlier value."
-  (cond ((and shift-select-mode this-command-keys-shift-translated)
+  (cond ((and (eq shift-select-mode 'permanent)
+              this-command-keys-shift-translated)
+         (unless mark-active
+           (push-mark nil nil t)))
+        ((and shift-select-mode
+              this-command-keys-shift-translated)
          (unless (and mark-active
 		      (eq (car-safe transient-mark-mode) 'only))
 	   (setq-local transient-mark-mode

bug#50038: Permanent shift-select-mode

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 50038@debbugs.gnu.org
> Date: Sun, 15 Aug 2021 11:37:48 +0300
> 
> > And finally, a question: is it enough to have this as a user option?
> > That is, what if the user wants this only temporarily, for the next
> > sequence of commands that extend the region?  Should we perhaps have a
> > better solution for that use case?  More generally, perhaps this
> > feature is almost always wanted only for a sequence of commands, never
> > globally for extended periods of time?  In that case, a user option is
> > not the best solution; it is better to have some minor mode that could
> > be turned on and off with a simple key sequence.
> 
> It would be very surprising if someone might want something more complicated.

So you, for example, will use this value at all times?

> This patch also adds a NEWS entry:

Thanks, LGTM.

bug#50038: Permanent shift-select-mode

[Juri Linkov]

tags 50038 fixed
close 50038 28.0.50
thanks

>> It would be very surprising if someone might want something more complicated.
>
> So you, for example, will use this value at all times?

Right, to me it makes sense not to deactivate the mark permanently
while typing non-shifted keys at all times.

>> This patch also adds a NEWS entry:
>
> Thanks, LGTM.

So now pushed to master.