Re: Any infrastructure to select one of a few options in Emacs core?

["Pascal J. Bourguignon" <pjb@informatimago.com>]

Marcin Borkowski <mbork@mbork.pl> writes:

> On 2016-05-09, at 19:27, Drew Adams <drew.adams@oracle.com> wrote:
>
>>> > completing-read
>>>
>>> Yes and no.  I thought about it, and rejected the idea: I want all the
>>> options to be visible without pressing TAB.  Also, each option might
>>> need more than one line (and the number of lines may vary between
>>> options), so I don't like the idea of using minibuffer at all.
>>
>> It's still not clear from your description what you mean by "select"
>> one of the options.
>
> OK, so let us assume that I want the user to select one of the three
> strings: "spam", "eggs" and "emacs".  (Note: in my use case they would
> not be string literals.)  Then, I'd like to be able to say, e.g.,
> something like this:
>
> (ask-user-for-option "What would you like to eat?" '("spam" "ham" "eggs"))
>
> and have something like
>
> Wat would you like to eat?
>
> 1. spam
>
> 2. ham
>
> 3. eggs
>
> displayed (perhaps in a *temp* buffer or so), and wait for the user to
> press 1, 2 or 3.  Then, the above form returns the selected string.
>
> It would probably be also useful to be able to give it e.g. cons cells
> with the car being the string and the cdr the value returned in case of
> selecting this particular string.  Also, it should be customizable: one
> user might like digit keys, another one letters, for instance.  Also,
> the choices should be clickable for those poor souls addicted to
> rodents.
>
> In a more advanced scenario, the menu might be "non-modal", i.e. do not
> use `read-key' or something like that, but a dynamically crafted mode
> (probably descendant of special-mode), in which various keys/clicks would
> launch a callback function given to the hypothetical
> `ask-user-for-option' with the selected choice as a parameter.

You can use a popup menu for that.

(let ((options '("spam" "ham" "eggs")))
  (x-popup-menu (let ((mp (mouse-position)))
                  (list (list (cadr mp)
                              (cddr mp))
                        (selected-window)))
                (list "menu"
                      (cons "What would yuo like to eat?"
                            (mapcar (lambda (option) (cons option option))
                                    options)))))
                                          
-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
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