bug#70833: 29.2.50; project-current: allow control of the prompt string

bug#70833: 29.2.50; project-current: allow control of the prompt string

[Spencer Baugh]

It would be nice to be able to control the prompt string that
project-current uses when prompting for a project.  Ideally, by passing
a string for the MAYBE-PROMPT argument.

This is useful when using project-current in functions which should
operate on the current project normally, but which might be run outside
any project and in that case will prompt for a project.  The user might
be uncertain about what the project they'll input will be used for,
exactly.  It's useful for the prompt to remind them.

The prompt could be passed down as an argument to project-prompter, or
bound in a defvar for compatibility - either seems fine to me.

bug#70833: 29.2.50; project-current: allow control of the prompt string

[Dmitry Gutov]

[-- Attachment #1: Type: text/plain, Size: 1391 bytes --]

Hi Spencer,

On 08/05/2024 17:05, Spencer Baugh wrote:
> 
> It would be nice to be able to control the prompt string that
> project-current uses when prompting for a project.  Ideally, by passing
> a string for the MAYBE-PROMPT argument.
> 
> This is useful when using project-current in functions which should
> operate on the current project normally, but which might be run outside
> any project and in that case will prompt for a project.  The user might
> be uncertain about what the project they'll input will be used for,
> exactly.  It's useful for the prompt to remind them.
> 
> The prompt could be passed down as an argument to project-prompter, or
> bound in a defvar for compatibility - either seems fine to me.

Aside from documentation changes, and the backward incompatibility 
pains, this looks easy enough to do.

Why do you say that that the lexical argument is better than a dynamic 
one in this case? Just wondering if you see a particular reason.

Also, I wonder if we perhaps should pass not the entire prompt but some 
"purpose hint". For example, the argument could look like "find-file", 
and then the prompt would be rendered as

   Select project [find-file]:

or however else the prompter implementation decides (perhaps it uses 
some other different UI where another text arrangement would be better). 
Just a thought -- I'm probably over-complicating things.


[-- Attachment #2: maybe-prompt-prompt.diff --]
[-- Type: text/x-patch, Size: 2378 bytes --]

diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index 52fe4df9080..b36cd1989f9 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -235,7 +235,9 @@ project-current
      (pr)
      ((unless project-current-directory-override
         maybe-prompt)
-      (setq directory (funcall project-prompter)
+      (setq directory (if (stringp maybe-prompt)
+                          (funcall project-prompter maybe-prompt)
+                        (funcall project-prompter))
             pr (project--find-in-directory directory))))
     (when maybe-prompt
       (if pr
@@ -1819,7 +1821,7 @@ project-forget-project
 
 (defvar project--dir-history)
 
-(defun project-prompt-project-dir ()
+(defun project-prompt-project-dir (&optional prompt)
   "Prompt the user for a directory that is one of the known project roots.
 The project is chosen among projects known from the project list,
 see `project-list-file'.
@@ -1837,14 +1839,15 @@ project-prompt-project-dir
       ;; If the user simply pressed RET, do this again until they don't.
       (setq pr-dir
             (let (history-add-new-input)
-              (completing-read "Select project: " choices nil t nil 'project--dir-history))))
+              (completing-read (or prompt "Select project: ")
+                               choices nil t nil 'project--dir-history))))
     (if (equal pr-dir dir-choice)
         (read-directory-name "Select directory: " default-directory nil t)
       pr-dir)))
 
 (defvar project--name-history)
 
-(defun project-prompt-project-name ()
+(defun project-prompt-project-name (&optional prompt)
   "Prompt the user for a project, by name, that is one of the known project roots.
 The project is chosen among projects known from the project list,
 see `project-list-file'.
@@ -1872,7 +1875,8 @@ project-prompt-project-name
       ;; If the user simply pressed RET, do this again until they don't.
       (setq pr-name
             (let (history-add-new-input)
-              (completing-read "Select project: " table nil t nil 'project--name-history))))
+              (completing-read (or prompt "Select project: ")
+                               table nil t nil 'project--name-history))))
     (if (equal pr-name dir-choice)
         (read-directory-name "Select directory: " default-directory nil t)
       (let ((proj (assoc pr-name choices)))