bug#67310: [PATCH] Include the project--list as history when prompting for a project

[Dmitry Gutov <dmitry@gutov.dev>]

I'll try to answer some of the questions that are still relevant to the 
latest patch, myself.

On 23/11/2023 08:38, Eli Zaretskii wrote:

>> +            ;; Iterate in reverse order so project--name-history is in
>> +            ;; the correct order.
> 
> What is the "correct" order?

Their order in project--list.

Iteration and construction of a new list with 'push' leads to the 
reverse order, hence the use of reversion at the beginning to counteract 
that.

>> -              (if-let (proj (project--find-in-directory dir))
>> -                  (push (cons (project-name proj) proj) ret)))
>> +              (when-let (proj (project--find-in-directory dir))
>> +                (let ((name (project-name proj)))
>> +                  (push name project--name-history)
>> +                  (push (cons name proj) ret))))
> 
> Not sure I understand why you replaced if-let with when-let here.

To reduce the amount of indentation, perhaps.

>> +            (let ((history-add-new-input nil))
> 
> Why this non-standard way of let-binding a variable to nil?

I use this myself sometimes to make the change more explicit.

Anyway, amended.

>> +        (let ((history-delete-duplicates t)
>> +              (history-length t))
>> +          (add-to-history 'project--list root))
> 
> Why are you overriding the values of these two user options?

To implement the current behavior (how additions to project--list) 
happen. I've described that behavior in one of the earlier messages here.

>> -  (let ((dirs (if recursive
>> -                  (directory-files-recursively dir "" t)
>> -                (directory-files dir t)))
>> -        (known (make-hash-table :size (* 2 (length project--list))
>> -                                :test #'equal))
>> -        (count 0))
>> -    (dolist (project (mapcar #'car project--list))
>> +  (let* ((dirs (if recursive
>> +                   (directory-files-recursively dir "" t)
>> +                 (directory-files dir t)))
>> +         (roots (project-known-project-roots))
>> +         (known (make-hash-table :size (* 2 (length roots))
>> +                                 :test #'equal))
>> +         (count 0))
> 
> Is it really necessary to use let* here?

'known' depend on 'roots'.