Are modal editing packages wrappers around multiple keymaps?
reddit / emacs

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talgu · 2022-09-25 14:55

I'm not very good at elisp, or programming in general, but I've been
reading through Modalka and Boon's source and I haven't really found
much that specifically says "this is the modal part" in big neon
letters.  But I did notice that Modalka defines fewer keymaps than
Boon does.  Modalka only provides two modes for editing and everything
else, while Boon provides more modes.

So I suspect that really what's happening is that they are managing
keymaps.  Is this actually true?  Or am I missing something important?

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SequentialDesign · 2022-09-25 15:57

yes, they can be (though, not necessarily). check out my comment on
the Modalka github page:

> Note that the target key binding cannot be a prefix key (prefix keys
will be ignored).

I'm not sure what you (Mark Karpov) mean by this, but I want to make
it clear that this works because it sounds like you mean prefix keys
are not possible with Modalka:

```
(setq keymap (make-sparse-keymap))
(define-key keymap "C-x" #'ctl-x-map)

(define-key modalka-mode-map "x" ctl-x-map)
(define-key ctl-x-map (kbd "e") 'eval-last-sexp)
(define-key ctl-x-map (kbd "s") 'save-buffer)
```
`x` works like `CTL-x` does. that is, x acts just like the normal
prefix key.

I think it's a game changer. hat tip to u/Horrih for the tip

PS apologies if I misunderstood you.

end of GitHub comment.

Modalka is great. and thanks again to Horrih for the great help

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7890yuiop · 2022-09-26 01:22

> I suspect that really what's happening is that they are managing
keymaps. Is this actually true?

If you type a key/sequence in Emacs and something happens, it's
because of a keymap.

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poiu- · 2022-09-26 07:00

Yes. Overriding keymaps, then managing the overrides.

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talgu · 2022-09-27 03:46

Thanks, stating it this way makes the whole thing fairly easy to
understand. :)

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talgu · 2022-09-27 03:47

This sounds like there's a lot of potential for things to become
messy.  I'm assuming that this means major/minor modes create keymaps
to do things.  Won't this lead to clashes?

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talgu · 2022-09-27 04:41

Could you explain a bit more about what you mean with "though, not
necessarily"?  That GitHub comment was very valuable thank you!  It
didn't occur to me that this is possible.

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7890yuiop · 2022-09-27 05:15

Read all of https://www.masteringemacs.org/article/mastering-key-
bindings-emacs -- it should explain most questions you might have
about keymaps and key bindings generally.

Clashes are in part covered by
https://www.gnu.org/software/emacs/manual/html_node/elisp/Key-Binding-
Conventions.html

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SequentialDesign · 2022-09-27 07:50

yeah, so, with Modalka, you can tap into other keymaps with Modalka's
standard translation abilities, e.g.
```
(modalka-define-kbd "a" "C-a") ; move-beginning-of-line
(modalka-define-kbd "e" "C-e") ; move-end-of-line
```
or you can create your own Modalka map that does not rely on anything
else
```
(define-key modalka-mode-map (kbd "a") #'move-beginning-of-line)
(define-key modalka-mode-map (kbd "e") #'move-end-of-line)
```
I think the "correct" way, if such a thing exists, is to tap into
other keymaps so that they are accessible when I'm not in Modalka,
like using `ctl-x-map` above. I believe this is proper technique. it's
easier to remember and accessible everywhere

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talgu · 2022-09-27 21:08

This is a really awesome idea thanks! :)  Do you think one could use
this technique to have one prefix key that defaults to the current
major mode?  Or would this have to be set for every mode?

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talgu · 2022-09-27 21:08

Thank you, I'll read through that. :)

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SequentialDesign · 2022-09-28 08:07

interest idea. i hadn't thought about it. i don't know