Re: Completion of links to man pages

[Ihor Radchenko <yantar92@posteo.net>]

Eli Zaretskii <eliz@gnu.org> writes:

>> Yes, but one cannot replicate the same completion dialogue
>> programmatically in future-compatible way.
>
> What do you mean by that?  "M-x man" does this:
>
>   (interactive
>    (list (let* ((default-entry (Man-default-man-entry))
> 		;; ignore case because that's friendly for bizarre
> 		;; caps things like the X11 function names and because
> 		;; "man" itself is case-insensitive on the command line
> 		;; so you're accustomed not to bother about the case
> 		;; ("man -k" is case-insensitive similarly, so the
> 		;; table has everything available to complete)
> 		(completion-ignore-case t)
> 		Man-completion-cache    ;Don't cache across calls.
> 		(input (completing-read
> 			(format-prompt "Manual entry"
>                                        (and (not (equal default-entry ""))
>                                             default-entry))
>                         'Man-completion-table
> 			nil nil nil 'Man-topic-history default-entry)))
>
> This uses completing-read, as I think you wanted.
> ...
> Why cannot you reuse Man-completion-table?
>
>> For now, as you can see in the quoted code from my initial message, we
>> have to partially replicate the code from man.el and woman.el:
>> 
>> (defun org-man--complete-man (prompt)
>>    (require 'man)
>>    (let (Man-completion-cache) ;; <- implementation detail in man.el
>>      (completing-read
>>       prompt
>>       'Man-completion-table)))
>
> And why is that a problem?

Because we also need to bind (completion-ignore-case t) and
(Man-completion-cache nil). Ideally, these details should not be
something we need to know. It would be better if man.el provided some
kind of API function like `man-completing-read' that takes care about
these details, which are apparently necessary to avoid bug#13160 and
bug#3717.

>> However, `Man-completion-table' is not documented (no docstring),
>
> If the only thing that's missing is its doc string, that is easy to
> add.

Docstring would certainly help. Otherwise, we have to guess what that
function does.

-- 
Ihor Radchenko // yantar92,
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