How to add a new keyboard layout to Emacs input methods?

Question

I've downloaded a new layout from https://qwerty-lafayette.org/ which I would like to use. However I am struggling to understand how I can use it inside Emacs. Usually I set languages by using (set-input-method "language"). However here I can't select the language, how can I do this for this particular language?

Answer 1

AFAIK there's not much documentation for the quail / leim stuff in Emacs; but once you know where to look, you can generally muddle your way through based on existing cases (there are so many of them, that there's generally likely to be something similar to use as a basis).

See M-x find-library RET leim-list for all of the register-input-method calls. To pick an example with a keyboard layout:

(register-input-method
 "english-dvorak" "English" 'quail-use-package
 "DV@" "English (ASCII) input method simulating Dvorak keyboard"
 "quail/latin-post")

The following is then a verbatim quote of the english-dvorak input method and keyboard layout from that quail/latin-post library. I believe that the call to quail-define-rules is automatically using the most-recent quail-define-package declaration, so this is pretty much all there is.

Note that you can visit that library with M-x find-library RET quail/latin-post (type it verbatim; completion won't complete it), and of course the many other files in the same directory provide other different examples.

Checking your link, I guess the better examples to look at are the french-keyboard and french-azerty input methods (which are also in latin-post.el). Once you have this working, perhaps you could contribute it upstream alongside those?

(require 'quail)

(quail-define-package
 "english-dvorak" "English" "DV@" t
 "English (ASCII) input method simulating Dvorak keyboard"
 nil t t t t nil nil nil nil nil t)

;; 1!  2@  3#  4$  5%  6^  7&  8*  9(  0)  [{  ]}  `~
;;  '"  ,<  .>  pP  yY  fF  gG  cC  rR  lL  /?  =+
;;   aA  oO  eE  uU  iI  dD  hH  tT  nN  sS  -_  \|
;;    ;:  qQ  jJ  kK  xX  bB  mM  wW  vV  zZ

(quail-define-rules
 ("-" ?\[)
 ("=" ?\])
 ("`" ?`)
 ("q" ?')
 ("w" ?,)
 ("e" ?.)
 ("r" ?p)
 ("t" ?y)
 ("y" ?f)
 ("u" ?g)
 ("i" ?c)
 ("o" ?r)
 ("p" ?l)
 ("[" ?/)
 ("]" ?=)
 ("a" ?a)
 ("s" ?o)
 ("d" ?e)
 ("f" ?u)
 ("g" ?i)
 ("h" ?d)
 ("j" ?h)
 ("k" ?t)
 ("l" ?n)
 (";" ?s)
 ("'" ?-)
 ("\\" ?\\)
 ("z" ?\;)
 ("x" ?q)
 ("c" ?j)
 ("v" ?k)
 ("b" ?x)
 ("n" ?b)
 ("m" ?m)
 ("," ?w)
 ("." ?v)
 ("/" ?z)

 ("_" ?{)
 ("+" ?})
 ("~" ?~)
 ("Q" ?\")
 ("W" ?<)
 ("E" ?>)
 ("R" ?P)
 ("T" ?Y)
 ("Y" ?F)
 ("U" ?G)
 ("I" ?C)
 ("O" ?R)
 ("P" ?L)
 ("{" ??)
 ("}" ?+)
 ("A" ?A)
 ("S" ?O)
 ("D" ?E)
 ("F" ?U)
 ("G" ?I)
 ("H" ?D)
 ("J" ?H)
 ("K" ?T)
 ("L" ?N)
 (":" ?S)
 ("\"" ?_)
 ("|" ?|)
 ("Z" ?:)
 ("X" ?Q)
 ("C" ?J)
 ("V" ?K)
 ("B" ?X)
 ("N" ?B)
 ("M" ?M)
 ("<" ?W)
 (">" ?V)
 ("?" ?Z)
 )

---

For a minimal example of a layout which switches the "f" and "o" characters, you could put this in your init file:

(add-to-list 'load-path (expand-file-name "~/.emacs.d/lisp"))

(register-input-method
 "foo" "French" 'quail-use-package
 "FOO@" "Example input method"
 "foo-input-method")

And create a file ~/.emacs.d/lisp/foo-input-method.el containing:

(require 'quail)

(quail-define-package
 "foo" "Foo" "Foo" t
 "Example input method"
 nil t t t t nil nil nil nil nil t)

(quail-define-rules
 ("F" ?O)
 ("f" ?o)
 ("O" ?F)
 ("o" ?f)
 )

(provide 'foo-input-method)