anonymous-commands-in-emacs
Table of Contents
Introduction
Generally, you do not want to make keybindings to anonymous lambdas. Here is the primary reason that comes to mind:
(describe-keymap (let ((m (make-sparse-keymap))) (define-key m (kbd "f") (lambda () (interactive) 'hi)) m))
I get help buffer with this content:
Key Binding f [closure]
It is not really useful to just get the info [closure] here.
add-hook
The same thing goes for add-hook. From the doc string:
FUNCTION may be any valid function, but it's recommended to use a function symbol and not a lambda form. Using a symbol will ensure that the function is not re-added if the function is edited, and using lambda forms may also have a negative performance impact when running `add-hook' and `remove-hook'
Some of the hooks functionality is meant for symbols.
Solution
Alias your function:
(defalias 'foo-a (lambda () (interactive) 'hi)) (describe-keymap (let ((m (make-sparse-keymap))) (define-key m (kbd "f") 'foo-a) (define-key m (kbd "b") (defalias 'foo-b (lambda () (interactive) 'hi2))) m))
Key Binding b foo-b f foo-a
Foo-b works because defalias returns the symbol.
defun
(defalias 'foo (lambda () (interactive)))
is essentially the same as
(defun foo () (interactive))
Result
I end up just using defun inline.
Examples:
(add-hook 'sh-mode-hook (defun mm/add-bash-completion () ...))
(mememacs/leader-def "pP" (defun mm/project-switch-project-find-file () (interactive) ...))
After writing this post, I went and fixed the remaining add-hook lambas In my config.