Overhaul counsel-yank-pop #1356

basil-conto · 2017-12-08T03:59:14Z

Changelog

Please see each commit message in order. The last and most significant commit in particular addresses this Emacs SE question and closes #1190.

Before merging

The function counsel--yank-pop-position is also useful in #1133. If that PR lands first, the function should be removed from this PR. Conversely, if this PR lands first, then #1133 should be rebased to avail of the function.

Question

Is completely ignoring blank kills really that useful? Thoughts on lifting this restriction or making it configurable?

- Hoist common branch code. - Heed carriage returns. - Consolidate nested lets.

Do not unnecessarily modify kill-ring structure and elements.

basil-conto · 2017-12-08T05:16:06Z

counsel.el

+    (setq ivy-completion-end (point))
+    (ivy-read "kill-ring: " cands
+              :require-match t
+              :preselect (nth (or arg 1) kill-ring-yank-pointer)


Woops, this is wrong for negative ARGs; I'll fix it later today.

ambihelical · 2017-12-08T06:18:34Z

counsel.el

-      (ivy-read "kill-ring: " candidates
-                :action 'counsel-yank-pop-action
-                :caller 'counsel-yank-pop))))
+                    (string-match "\\`[\n\r[:blank:]]*\\'" s))


Potentially replaceable with string-blank-p

ambihelical · 2017-12-08T06:20:33Z

counsel.el

-                  (delete-dups kill-ring))))
+  (let ((cands (delete-dups
+                (cl-mapcan (lambda (s)
+                             (unless (string-match-p "\\`[\n\r[:blank:]]*\\'" s)


potentially use string-blank-p here.

basil-conto · 2017-12-08T15:49:28Z

@ambihelical I would have used string-blank-p too, but the [:blank:] character class matches Unicode whitespace in addition to just tabs and spaces in Emacs 25+. Probably string-blank-p should be updated to use [:blank:].

I'm more concerned about whether we should unconditionally be removing all blank kills from the candidates offered.

basil-conto · 2017-12-08T17:00:43Z

While trying to fix the :preselect calculation, I realised that filtering kill-ring elements only for the sake of Ivy completion is Doing The Wrong Thing. In particular, it makes relative offsets into the kill-ring inconsistent and meaningless and does not integrate nicely with Emacs.

Nevertheless, I understand why users may want to ignore certain kill-ring elements. I can think of three approaches counsel.el can take in order to Do The Right Thing:

1. Leave the kill ring alone

(elisp) Kill Functions explains that Emacs offers mechanisms for filtering killed text which users can modify to suit their preferences, though I'm not sure whether these can omit blank strings altogether.

Pros:

Less to worry about.
Consistent and reliable candidate preselecting.
Consistency and integration with broader kill ring ecosystem.

Cons:

Less convenient for and friendly to users.
Potentially offers no automated way to ignore blank kills.

2. Modify the kill ring; long live the kill ring!

If counsel.el does not want to offer blank kills during completion, it should completely and destructively remove them from the kill ring. Perhaps a regexp/function user option can be provided for customising the filtering operation.

Pros:

Consistent and reliable candidate preselecting. Kind of; the user has to keep in mind that relative positions into the kill ring skip blank kills.
Consistency and integration with broader kill ring ecosystem.

Cons:

Some users (including myself) are opposed to / squeamish about modifying the kill ring.
Intrusive / non-Emacsy.

3. All of the above

Provide a toggle between leaving the kill ring untouched and destructively filtering it.

Pros:

Union of pros of approaches 1 and 2.

Cons:

Intersection of cons of approaches 1 and 2.

My personal favorite is 3, for which I'd be happy to provide the code. Thoughts?

basil-conto · 2017-12-08T17:24:30Z

I've fixed the :preselect calculation for now with a bit of a hack.

The command yank-pop does too much under the bonnet to ever hope to emulate, so use it directly. This respects and updates various internals, most noticeably kill-ring-yank-pointer, thus allowing consecutive calls to yank to work. See https://emacs.stackexchange.com/q/37351/15748. (counsel--yank-pop-position): New function. (counsel-yank-pop-action): Use yank-pop. (counsel-yank-pop): Do The Right Thing w.r.t. point and mark regardless of whether last-command was a yank. Adopt interactive-spec of yank-pop and preselect candidate accordingly. Abort on empty/blank kill-ring. Fixes abo-abo#1190

abo-abo · 2017-12-08T18:28:27Z

Thanks.

I realised that filtering kill-ring elements only for the sake of Ivy completion is Doing The Wrong Thing

You mean deleting blanks from the kill-ring? I have no problem with doing that. If it's an issue for you, PR with removing blanks non-destructively.

basil-conto · 2017-12-08T22:27:36Z

You mean deleting blanks from the kill-ring?

Not exactly. What I think is The Wrong Thing is a) not giving users the choice to complete kill-ring contents without any filtering; and b) having differences between the contents of kill-ring and the completion collection which counsel-yank-pop offers.

Point (a) is simply about user preference. Point (b), on the other hand, is a more subtle problem because many kill/yank commands operate in terms of relative offsets of kill-ring-yank-pointer within kill-ring. When, for example, counsel-yank-pop only displays half the contents of kill-ring, then commands like rotate-yank-pointer, which operate on an unfiltered kill-ring, are likely to give unexpected results.

This is why I think it is important to accompany filtering of kill-ring with actual deletion of filtered elements, so that all kill/yank commands remain consistent and correct.

If that sounds good to you I'll submit another PR to allow toggling kill-ring filtering and accompanying filtering with actual deletion.

abo-abo · 2017-12-09T09:57:12Z

If that sounds good to you I'll submit another PR to allow toggling kill-ring filtering and accompanying filtering with actual deletion.

Thanks for the explanation. Please PR, with deletion on by default.

(counsel-string-non-blank-p): New function. (counsel-yank-pop-filter): New defcustom defaulting to it. (counsel--yank-pop-kills): Use it to destructively filter and uniquify kill-ring and kill-ring-yank-pointer elements. (counsel-yank-pop-action-remove, counsel-yank-pop): Consistently test equivalence with equal-including-properties. Re: abo-abo#1356

(counsel-string-non-blank-p): New function. (counsel-yank-pop-filter): New defcustom defaulting to it. (counsel--yank-pop-kills): Use it to destructively filter and uniquify kill-ring and kill-ring-yank-pointer elements. (counsel-yank-pop-action-remove, counsel-yank-pop): Consistently test equivalence with equal-including-properties. Re: #1356 Fixes #1367

basil-conto added 3 commits December 8, 2017 03:53

counsel.el (counsel-yank-pop): Minor touch-ups

5701573

- Hoist common branch code. - Heed carriage returns. - Consolidate nested lets.

counsel.el (counsel-yank-pop): Make purer

24517eb

Do not unnecessarily modify kill-ring structure and elements.

counsel.el (counsel-yank-pop-truncate-radius): Doc fix

5ad7ae8

basil-conto mentioned this pull request Dec 8, 2017

Interoperate better with kill-ring #1133

Closed

basil-conto force-pushed the yank-pop branch 2 times, most recently from cb7c858 to e0c2bad Compare December 8, 2017 04:14

basil-conto commented Dec 8, 2017

View reviewed changes

ambihelical reviewed Dec 8, 2017

View reviewed changes

basil-conto force-pushed the yank-pop branch from e0c2bad to de5dd01 Compare December 8, 2017 17:23

basil-conto force-pushed the yank-pop branch from de5dd01 to c1941f0 Compare December 8, 2017 17:29

abo-abo closed this in 50aa561 Dec 8, 2017

basil-conto deleted the yank-pop branch December 8, 2017 19:26

basil-conto mentioned this pull request Dec 10, 2017

counsel.el: Make kill-ring filtering configurable #1367

Closed

Overhaul counsel-yank-pop #1356

Overhaul counsel-yank-pop #1356

basil-conto commented Dec 8, 2017

basil-conto Dec 8, 2017

ambihelical Dec 8, 2017

ambihelical Dec 8, 2017

basil-conto commented Dec 8, 2017

basil-conto commented Dec 8, 2017

basil-conto commented Dec 8, 2017

abo-abo commented Dec 8, 2017

basil-conto commented Dec 8, 2017 •

edited

abo-abo commented Dec 9, 2017

Overhaul counsel-yank-pop #1356

Overhaul counsel-yank-pop #1356

Conversation

basil-conto commented Dec 8, 2017

Changelog

Before merging

Question

basil-conto Dec 8, 2017

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basil-conto commented Dec 8, 2017

basil-conto commented Dec 8, 2017

1. Leave the kill ring alone

2. Modify the kill ring; long live the kill ring!

3. All of the above

basil-conto commented Dec 8, 2017

abo-abo commented Dec 8, 2017

basil-conto commented Dec 8, 2017 • edited

abo-abo commented Dec 9, 2017

basil-conto commented Dec 8, 2017 •

edited