Re: [Patch] Add project.el command to replace symbol at point throughout project

[Jon Eskin <eskinjp@gmail.com>]

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Apologies- in the event that this patch is satisfactory, the following includes `xref-find-references-and-replace`. I didn’t realize it would be a simple replacement. 

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From 3d575a12107daa09fdb0efc0397ff8c7affa9b1a Mon Sep 17 00:00:00 2001
From: Jon Eskin <eskinjp@gmail.com>
Date: Fri, 14 Jan 2022 10:03:30 -0500
Subject: [PATCH] Use symbol at point as default for query-replace-read-args

* lisp/progmodes/project.el
(project-query-replace-regexp): Let-bind
`read-regexp-defaults-function` to default to symbol at point.

* lisp/replace.el
(query-replace-read-from): Don't format prompt if there's a symbol at
point, otherwise read-regexp is forced to use the wrong prompt.

* lisp/progmodex/xref.el (xref-find-references): Let-bind
`read-regexp-defaults-function` to default to symbol at point
---
 lisp/progmodes/project.el |  8 +++++---
 lisp/progmodes/xref.el    |  4 +++-
 lisp/replace.el           | 10 ++++++----
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index c812f28c1b..b44b23554f 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -1072,9 +1072,11 @@ project-query-replace-regexp
 If you exit the `query-replace', you can later continue the
 `query-replace' loop using the command \\[fileloop-continue]."
   (interactive
-   (pcase-let ((`(,from ,to)
-                (query-replace-read-args "Query replace (regexp)" t t)))
-     (list from to)))
+   (let ((read-regexp-defaults-function (lambda ()
+                                          (find-tag-default-as-regexp))))
+    (pcase-let ((`(,from ,to)
+                 (query-replace-read-args "Query replace (regexp)" t t)))
+      (list from to))))
   (fileloop-initialize-replace
    from to (project-files (project-current t)) 'default)
   (fileloop-continue))
diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index a1e976cb1c..5336c319bb 100644
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -1481,7 +1481,9 @@ xref-find-references
 (defun xref-find-references-and-replace (from to)
   "Replace all references to identifier FROM with TO."
   (interactive
-   (let ((common
+   (let* ((common
+          (read-regexp-defaults-function (lambda ()
+                                          (find-tag-default-as-regexp)))
           (query-replace-read-args "Query replace identifier" nil)))
      (list (nth 0 common) (nth 1 common))))
   (require 'xref)
diff --git a/lisp/replace.el b/lisp/replace.el
index 60e507c642..3d7648611b 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -208,7 +208,8 @@ query-replace-read-from
 wants to replace FROM with TO."
   (if query-replace-interactive
       (car (if regexp-flag regexp-search-ring search-ring))
-    (let* ((history-add-new-input nil)
+    (let* ((sym-at-point (symbol-at-point))
+           (history-add-new-input nil)
 	   (separator-string
 	    (when query-replace-from-to-separator
 	      ;; Check if the first non-whitespace char is displayable
@@ -234,8 +235,9 @@ query-replace-read-from
 	     (symbol-value query-replace-from-history-variable)))
 	   (minibuffer-allow-text-properties t) ; separator uses text-properties
 	   (prompt
-	    (cond ((and query-replace-defaults separator)
-                   (format-prompt prompt (car minibuffer-history)))
+	    (cond (sym-at-point prompt) ;; if there's a symbol at point, let read-regexp format the prompt
+                  ((and query-replace-defaults separator)
+                     (format-prompt prompt (car minibuffer-history)))
                   (query-replace-defaults
                    (format-prompt
                     prompt (format "%s -> %s"
@@ -255,7 +257,7 @@ query-replace-read-from
                                 (append '((separator . t) (face . t))
                                         text-property-default-nonsticky)))
                 (if regexp-flag
-                    (read-regexp prompt nil 'minibuffer-history)
+                    (read-regexp prompt sym-at-point 'minibuffer-history)
                   (read-from-minibuffer
                    prompt nil nil nil nil
                    (query-replace-read-from-suggestions) t)))))
-- 
2.34.1


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> On Jan 15, 2022, at 4:55 AM, Jon Eskin <eskinjp@gmail.com> wrote:
> 
> 
> 
>> On Jan 14, 2022, at 3:28 PM, Dmitry Gutov <dgutov@yandex.ru> wrote:
>> 
>> On 14.01.2022 12:26, Jon Eskin wrote:
>>>> So Jon, if you fancy writing a patch in this area, you can try implementing what Juri suggested:
>>>> 
>>>> let-bind read-regexp-defaults-function around the call
>>>> of query-replace-read-args, and use a symbol at point as the default.
>>>> 
>>>> That can apply to both project-query-replace-regexp and xref-find-references-and-replace.
>>> On it! I might take a little while but I'll check in if I get stuck.
>> 
>> Yeah, don't hesitate to ask questions if/when you have any.
> 
> 
> Hey all,
> 
> I took a stab at the implementation Juri described for `project-query-replace-regexp` and I was able to get the correct behavior, but I wanted to check in and see if it needs improvements before looking at `xref-find-references-and-replace.`
> 
> When I first let-bound `read-regexp-defaults-function` around the call to `query-replace-read-args`, it didn't work- it looks like `read-regexp` needs to be passed a symbol for its `DEFAULTS` parameter or it ignores `read-regexp-default-function`. I passed in the symbol at point to `DEFAULTS` which works- if I understand correctly the value of any I pass in doesn't end up making a difference as long as it's a symbol. I wasn't sure what the reason was for that behavior, but I didn't want to mess with stuff I didn't understand.
> 
> Another issue is that hardcoded logic in `read-regexp`:
> 
> 'If PROMPT ends in \":\" (followed by
> optional whitespace), use it as-is.  Otherwise, add \": \" to the end,
> possibly preceded by the default result (see below).'
> 
> The PROMPT passed into read-regexp does end in a ":" due to it being formatted by a call to `format-prompt` in `query-replace-read-from`. As a result, when the symbol is at point, `read-regexp` display the prompt with the last replacement from history. To address this, I added a cond case where the formatting takes place and omit the formatting step when there is a symbol at point so that `read-regex` will correctly format the prompt with the symbol at point. 
> 
> The result is that a call to `project-query-replace-regexp` will take the symbol at point as the default when available, otherwise it will use its previous behavior of defaulting to the last replacement available in history.
> 
> Let me know what you think.
> 
> <0001-Use-symbol-at-point-as-default-for-query-replace-rea.patch>