If you want to define a key for inserting a Unicode character such as math symbol λ, the best way is to use key-translation-map.
Example of using
define-key with key-translation-map:
(define-key key-translation-map (kbd "<f8>") (kbd "λ")) ; 【F8】 insert λ char
;; set keys to type Unicode (define-key key-translation-map (kbd "<f9> u <down>") (kbd "↓")) (define-key key-translation-map (kbd "<f9> u <left>") (kbd "←")) (define-key key-translation-map (kbd "<f9> u <right>") (kbd "→")) (define-key key-translation-map (kbd "<f9> u <up>") (kbd "↑"))
You could also use
global-set-key, like this:
(global-set-key (kbd "<f8>") (lambda () (interactive) (insert "λ"))) ;; or (global-set-key (kbd "<f8>") "λ") ; macro shortcut. doesn't work as well as using lambda
But it has problems. If you use
global-set-key, then when you do interactive search 【Ctrl+s】, then when you type your key, it'll exit the search instead of inserting the char.
Using key-translation-map doesn't have this problem.
key-translation-map is more low level.
You can use it to swap keys.
;; swap keys (define-key key-translation-map (kbd "<f11>") (kbd "<f12>")) (define-key key-translation-map (kbd "<f12>") (kbd "<f11>"))
Note: there's the function
keyboard-translate. However, it is designed to translate character only. So, key combination isn't a character and you can't use it for Hyper combination. Using
(define-key key-translation-map …) is more versatile. (Due to historical reasons,
keyboard-translate does work for some Ctrl combination key. (thanks to
Stefan Monnier and Deniz Dogan
for this tip. (Source groups.google.com)))
Using proper symbols can decreases ambiguity at syntax level. Examples:
For example, bullet (•), “curly quote”, dash (—), angle bracket for 《article title》 and 《book title》 〔➤ Intro to Chinese Punctuation〕, and i use 【lenticular bracket】 to mark keyboard shortuct, 「corner bracket」 to mark computer code, and i use FULLWIDTH AMPERSAND (＆) to avoid HTML entity complexity 〔➤ HTML Entities, Ampersand, Unicode, Semantics〕.
Using proper symbols decreases ambiguity at syntax level. For example, the ASCII asterisk (*) can mean lots of things. But a dedicated bullet “•” carries a precise semantics.
α = 3 instead of
alpha = 3). See: