Subject: Re: bug#66224: [PATCH] Add optional PREDICATE argument to read-directory-name

From: Joseph Turner <[email-masked]>
Date: Sun, 12 Nov 2023 12:42:42 -0800

Joseph Turner <[email-masked]> writes:

> Michael Heerdegen <[email-masked]> writes:
>
>> Joseph Turner via "Bug reports for GNU Emacs, the Swiss army knife of
>> text editors" <[email-masked]> writes:
>>
>>> I'm not sure what you mean. In both of the following examples, PREDICATE
>>> is used to narrow the completion candidates to only empty directories:
>>>
>>> (read-directory-name "Prompt: " "~/" nil t nil #'directory-empty-p)
>>> (read-directory-name "Prompt: " "~/" nil nil nil #'directory-empty-p)
>>
>> In the second version also non-empty directories will be accepted.
>
> Yes, PREDICATE narrows the completion candidates but doesn't determine a
> valid return value.

Ping!  I'm happy to keep discussing this patch if others are interested.