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

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

[Marcin Borkowski]

Hi all,

is there anything in core Emacs (i.e., no Melpa, and preferably no Elpa)
to facilitate selecting one of a few (say, up to 10) options, each
described in 2-3 lines of text?  (I know about the Widget library, but
I'd prefer something more lightweight.)

TIA,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[Drew Adams]

> is there anything in core Emacs (i.e., no Melpa, and preferably no Elpa)
> to facilitate selecting one of a few (say, up to 10) options, each
> described in 2-3 lines of text?  (I know about the Widget library, but
> I'd prefer something more lightweight.)

Dunno what you mean.  There is menu-bar menu `Options' (which)
you can add to.  There is Customize, which you can add to
with `defcustom'.

Specify "facilitate selection one of a few options".

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

[Marcin Borkowski]

On 2016-05-09, at 16:13, Drew Adams <drew.adams@oracle.com> wrote:

>> is there anything in core Emacs (i.e., no Melpa, and preferably no Elpa)
>> to facilitate selecting one of a few (say, up to 10) options, each
>> described in 2-3 lines of text?  (I know about the Widget library, but
>> I'd prefer something more lightweight.)
>
> Dunno what you mean.  There is menu-bar menu `Options' (which)
> you can add to.  There is Customize, which you can add to
> with `defcustom'.
>
> Specify "facilitate selection one of a few options".

Sorry for being imprecise.

I'd like to have (kind of) a menu, perhaps in a temporary buffer,
displaying a list of options and giving a way to select one of them.
Like, say clocking into one of recently clocked tasks in Org, or the
main manu in mu4e, or the possible corrections in ispell etc.  It seems
that a lot of packages use their own mechanism to do something like
that; now that I think of it, I guess it would be nice to have
a "canonical" way.  One advantage would be that by customizing this
"default" way, the user could define his/her preferred way of showing
the menu/selecting the option for _all_ applications using it.

WDYT?  Is there anything like that in Emacs?


-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[Kaushal Modi]

On Mon, May 9, 2016 at 11:41 AM Marcin Borkowski <mbork@mbork.pl> wrote:

> I'd like to have (kind of) a menu, perhaps in a temporary buffer,
> displaying a list of options and giving a way to select one of them.
> Like, say clocking into one of recently clocked tasks in Org, or the
> main manu in mu4e, or the possible corrections in ispell etc.  It seems
> that a lot of packages use their own mechanism to do something like
> that; now that I think of it, I guess it would be nice to have
> a "canonical" way.  One advantage would be that by customizing this
> "default" way, the user could define his/her preferred way of showing
> the menu/selecting the option for _all_ applications using it.
>
> WDYT?  Is there anything like that in Emacs?


I haven't used it directly. But someone please correct me if I am wrong;
doesn't the inbuilt completing-read already do this?

Packages like ivy.el have ivy-completing-read which conforms to the default
completing-read, and can be easily used to enhance that.
-- 

-- 
Kaushal Modi

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

[Marcin Borkowski]

On 2016-05-09, at 18:37, Kaushal Modi <kaushal.modi@gmail.com> wrote:

> On Mon, May 9, 2016 at 11:41 AM Marcin Borkowski <mbork@mbork.pl> wrote:
>
>> I'd like to have (kind of) a menu, perhaps in a temporary buffer,
>> displaying a list of options and giving a way to select one of them.
>> Like, say clocking into one of recently clocked tasks in Org, or the
>> main manu in mu4e, or the possible corrections in ispell etc.  It seems
>> that a lot of packages use their own mechanism to do something like
>> that; now that I think of it, I guess it would be nice to have
>> a "canonical" way.  One advantage would be that by customizing this
>> "default" way, the user could define his/her preferred way of showing
>> the menu/selecting the option for _all_ applications using it.
>>
>> WDYT?  Is there anything like that in Emacs?
>
>
> I haven't used it directly. But someone please correct me if I am wrong;
> doesn't the inbuilt completing-read already do this?
>
> Packages like ivy.el have ivy-completing-read which conforms to the default
> completing-read, and can be easily used to enhance that.

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.

Thanks anyway,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[Drew Adams]

> > 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.

Please specify how commands such as `customize', `customize-apropos'
do not do what you want.

`M-x customize-apropos-options RET .* RET', for example, shows you all
currently defined options, together with their doc string first line
(and full information if you expand an option description).

---

Emacs used to also have a command `edit-options', which listed all
options with their doc strings, and which had these keys:

 Options mode:
 Major mode for editing Emacs user option settings.
 Special commands are:
 s -- set variable point points at.  New value read using minibuffer.
 x -- toggle variable, t -> nil, nil -> t.
 1 -- set variable to t.
 0 -- set variable to nil.
 Changed values made by these commands take effect immediately.

 Each variable description is a paragraph.
 For convenience, the characters p and n move back and forward by
 paragraphs.

This feature was removed before Emacs 22, however.

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

[Marcin Borkowski]

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

--8<---------------cut here---------------start------------->8---
Wat would you like to eat?

1. spam

2. ham

3. eggs
--8<---------------cut here---------------end--------------->8---

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.

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[Drew Adams]

> (ask-user-for-option "What would you like to eat?" '("spam" "ham" "eggs"))

So this has nothing to do with Emacs _options_.

You are asking how to present some choices to a user for
selection.

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

[Pascal J. Bourguignon]

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/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk

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

[Emanuel Berg]

Marcin Borkowski <mbork@mbork.pl> writes:

> ...

Check out my 'buc' module! (I don't remember why
I called it that.)

It is actually brilliant. You have a bunch of
options: A, B, ... N.

Then you have keys on your keyboard: RET, SPC, TAB,
DEL, that are close and fast and singular.

So there is an association between the options, and
the keys!

But the genius of it is, if you don't care for any
of the options displayed and shortcutted, just type!
Any other char will take away the whole "buc prompt"
and instead appear as the first char in the input
string, i.e., an arbitrary string is still inputable!

Also, I added a function so that it works like
a cache, with the most recently selected option
always being the leftmost (RET), and then sorted
rightways... It is an open question if this really is
beneficial - it can be frustrating as well, if the
keys keep moving around! It should at least
be disableable.

A screenshot:

    http://user.it.uu.se/~embe8573/dumps/buc.png

The source:

    http://user.it.uu.se/~embe8573/conf/emacs-init/buc.el

-- 
underground experts united .... http://user.it.uu.se/~embe8573
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Re: Any infrastructure to select one of a few options in Emacs core?

[Emanuel Berg]

"Pascal J. Bourguignon" <pjb@informatimago.com>
writes:

> (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)))))

Cute, but is there any reason not to use the ordinary
minibuffer/echo area area for this as for everything
else? The whole thing with Emacs, or at least part of
the whole thing, is to have a uniform interface.

-- 
underground experts united .... http://user.it.uu.se/~embe8573
Emacs Gnus Blogomatic ......... http://user.it.uu.se/~embe8573/blogomatic
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Re: Any infrastructure to select one of a few options in Emacs core?

[Marcin Borkowski]

On 2016-05-09, at 20:16, Drew Adams <drew.adams@oracle.com> wrote:

>> (ask-user-for-option "What would you like to eat?" '("spam" "ham" "eggs"))
>
> So this has nothing to do with Emacs _options_.
>
> You are asking how to present some choices to a user for
> selection.

Yes, sorry for the confusion.

I went with this code:

--8<---------------cut here---------------start------------->8---
(defun select-choice (message choices)
  "Display a buffer with MESSAGE and then CHOICES.
Each element of CHOICES should be a cons cell, whose car is the
result and the cdr is the description.  The user may select one
by pressing a digit."
  ;; TODO: This function is way too simple and not fool-proof!
  (if (> (length choices) 9)
      (error "Too many choices!")
    (save-window-excursion
      (pop-to-buffer " *amsrefs doi selection*" t t)
      (delete-other-windows)		; TODO: this should be fixed
      (erase-buffer)
      (insert message "\n\n")
      (let ((i 0))
	(dolist (choice choices)
	  (setq i (1+ i))
	  (insert (format "%d. %s\n\n" i (cdr choice)))))
      (let ((key (read-key)))
	(if (<= 49 key 57)
	    (car (nth (- key 49) choices))
	  (error "Wrong key pressed!"))))))
--8<---------------cut here---------------end--------------->8---

As it is said in the comment, it is far from ideal, but the whole
program I've been writing for my friend is one big quick hack, so
I didn't bother too much.

Still, it would be really nice if Emacs offered a canonical (and
configurable) way to do things like that.

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[John Mastro]

Marcin Borkowski <mbork@mbork.pl> wrote:
> I went with this code:
>
> --8<---------------cut here---------------start------------->8---
> (defun select-choice (message choices)
>   "Display a buffer with MESSAGE and then CHOICES.
> Each element of CHOICES should be a cons cell, whose car is the
> result and the cdr is the description.  The user may select one
> by pressing a digit."
>   ;; TODO: This function is way too simple and not fool-proof!
>   (if (> (length choices) 9)
>       (error "Too many choices!")
>     (save-window-excursion
>       (pop-to-buffer " *amsrefs doi selection*" t t)
>       (delete-other-windows)            ; TODO: this should be fixed
>       (erase-buffer)
>       (insert message "\n\n")
>       (let ((i 0))
>         (dolist (choice choices)
>           (setq i (1+ i))
>           (insert (format "%d. %s\n\n" i (cdr choice)))))
>       (let ((key (read-key)))
>         (if (<= 49 key 57)
>             (car (nth (- key 49) choices))
>           (error "Wrong key pressed!"))))))
> --8<---------------cut here---------------end--------------->8---
>
> As it is said in the comment, it is far from ideal, but the whole
> program I've been writing for my friend is one big quick hack, so
> I didn't bother too much.

I've sometimes wanted something like this too.

I played around with a few cosmetic changes to your function and ended
up with this:

(defun read-choice (prompt choices)
  (if (> (length choices) 9)
      (error "Too many choices (max 9)")
    (let ((cursor-in-echo-area t)
          (prompt (if (get-text-property 0 'face prompt)
                      prompt
                    (propertize prompt
                                'face
                                'minibuffer-prompt))))
      (save-window-excursion
        (pop-to-buffer " *Read choice*" t t)
        (setq-local cursor-type nil)
        (erase-buffer)
        (let ((i 0))
          (dolist (choice choices)
            (setq i (1+ i))
            (insert (propertize (number-to-string i)
                                'face
                                'font-lock-variable-name-face)
                    (format " %s\n" (cdr choice))))
          (goto-char (point-min))
          (fit-window-to-buffer)
          (let ((key (- (read-key prompt) 48)))
            (if (<= 1 key i)
                (car (nth (1- key) choices))
              (user-error "Invalid key"))))))))

Same functionality but posted anyway in the spirit of sharing :)

Why did you find `delete-other-windows' necessary? (Your TODO mentions
that it should be "fixed", so I assume you would have preferred not to
use it.)

        John

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

[John Mastro]

John Mastro <john.b.mastro@gmail.com> wrote:

> I played around with a few cosmetic changes to your function and ended
> up with this:

I realized that, for my use case, it makes more sense to let the caller
specify the characters rather than automatically using the digits 1-9.
So I ended up with this instead, which is also a bit shorter and
simpler.

(defun read-choice (prompt choices)
  (let ((cursor-in-echo-area t)
        (prompt (if (get-text-property 0 'face prompt)
                    prompt
                  (propertize prompt
                              'face
                              'minibuffer-prompt))))
    (save-window-excursion
      (pop-to-buffer " *Read choice*" t t)
      (setq-local cursor-type nil)
      (erase-buffer)
      (pcase-dolist (`(,char ,description) choices)
        (insert (propertize (string char)
                            'face
                            'font-lock-variable-name-face)
                (format " %s\n" description)))
      (goto-char (point-min))
      (fit-window-to-buffer)
      (or (assoc (read-key prompt) choices)
          (user-error "Invalid selection")))))

In Emacs's master branch (but not the emacs-25 release branch) there's a
new function `read-multiple-choice' that's similar in purpose and worth
a look.

        John

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

[Marcin Borkowski]

On 2016-05-21, at 01:52, John Mastro <john.b.mastro@gmail.com> wrote:

> John Mastro <john.b.mastro@gmail.com> wrote:
>
>> I played around with a few cosmetic changes to your function and ended
>> up with this:
>
> I realized that, for my use case, it makes more sense to let the caller
> specify the characters rather than automatically using the digits 1-9.
> So I ended up with this instead, which is also a bit shorter and
> simpler.
>
> (defun read-choice (prompt choices)
>   (let ((cursor-in-echo-area t)
>         (prompt (if (get-text-property 0 'face prompt)
>                     prompt
>                   (propertize prompt
>                               'face
>                               'minibuffer-prompt))))
>     (save-window-excursion
>       (pop-to-buffer " *Read choice*" t t)
>       (setq-local cursor-type nil)
>       (erase-buffer)
>       (pcase-dolist (`(,char ,description) choices)
>         (insert (propertize (string char)
>                             'face
>                             'font-lock-variable-name-face)
>                 (format " %s\n" description)))
>       (goto-char (point-min))
>       (fit-window-to-buffer)
>       (or (assoc (read-key prompt) choices)
>           (user-error "Invalid selection")))))

Nice, thanks!  I didn't know about several things you used here - every
day is an opportunity to learn!  (I'll finally have to read about pcase,
too.)  I like especially the `fit-window-to-buffer' function - it seems
it's exactly what I needed, much better than my `delete-other-windows'!

Also, it seems you don't need `setq-local' here, since `cursor-type' is
automatically buffer-local anyway.

> In Emacs's master branch (but not the emacs-25 release branch) there's a
> new function `read-multiple-choice' that's similar in purpose and worth
> a look.

Yes, I've seen that.  Not useful for me, though -- in my use case the
descriptions of the choices are too long (maybe even several lines!).

>         John

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[Marcin Borkowski]

On 2016-05-09, at 20:36, Pascal J. Bourguignon <pjb@informatimago.com> wrote:

> 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)))))

Thanks a lot, I'll remember about `x-popup-menu', it might be useful one
day.  It's not what I like, though; I prefer to have everything
(including menus) in buffers.  (Well, almost everything.)

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[Marcin Borkowski]

On 2016-05-14, at 06:18, Emanuel Berg <embe8573@student.uu.se> wrote:

> Marcin Borkowski <mbork@mbork.pl> writes:
>
>> ...
>
> Check out my 'buc' module! (I don't remember why
> I called it that.)
>
> It is actually brilliant. You have a bunch of
> options: A, B, ... N.
>
> Then you have keys on your keyboard: RET, SPC, TAB,
> DEL, that are close and fast and singular.
>
> So there is an association between the options, and
> the keys!
>
> But the genius of it is, if you don't care for any
> of the options displayed and shortcutted, just type!
> Any other char will take away the whole "buc prompt"
> and instead appear as the first char in the input
> string, i.e., an arbitrary string is still inputable!
>
> Also, I added a function so that it works like
> a cache, with the most recently selected option
> always being the leftmost (RET), and then sorted
> rightways... It is an open question if this really is
> beneficial - it can be frustrating as well, if the
> keys keep moving around! It should at least
> be disableable.

Do I get it correctly that you have reinvented hydra?  (Or the other way
round;-).)

Though the idea of sorting by recent-ness is nice.

Thanks!

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University

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

[Emanuel Berg]

Marcin Borkowski <mbork@mbork.pl> writes:

>> Check out my 'buc' module! (I don't remember
>> why I called it that.) It is actually
>> brilliant. You have a bunch of options: A,
>> B, ... N. Then you have keys on your
>> keyboard: RET, SPC, TAB, DEL, that are close
>> and fast and singular. So there is an
>> association between the options, and the
>> keys! But the genius of it is, if you don't
>> care for any of the options displayed and
>> shortcutted, just type! Any other char will
>> take away the whole "buc prompt" and instead
>> appear as the first char in the input
>> string, i.e., an arbitrary string is still
>> inputable! Also, I added a function so that
>> it works like a cache, with the most
>> recently selected option always being the
>> leftmost (RET), and then sorted rightways...
>> It is an open question if this really is
>> beneficial - it can be frustrating as well,
>> if the keys keep moving around! It should at
>> least be disableable.
>
> Do I get it correctly that you have
> reinvented hydra? (Or the other way
> round;-).)

If it does the same thing, perhaps I should
rebrand mine "Chimera and the Gorgons"?

-- 
underground experts united .... http://user.it.uu.se/~embe8573
Emacs Gnus Blogomatic ......... http://user.it.uu.se/~embe8573/blogomatic
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