Binding similar commands from different modes to the same key

Question

I use emacs in multiple modes (ESS, Auctex, Slime, elisp, etc...) all using evil-mode key-bindings. Each of the interaction modes have similar functions for evaluating regions, lines or buffers that I have bound to shortcuts using spacebar as a prefix.

;; bind slime's eval and elisp eval to the key sequence "<SPC>e"
(evil-define-key 'normal lisp-mode-map (kbd "<SPC>e") 'slime-eval-last-expression)
(evil-define-key 'normal lisp-interaction-mode-map (kbd "<SPC>e") 'eval-last-sexp)

I would like to set a default key for a "type" of function, so that I don't need to have an entry like the above for every interaction mode I use and for every command. This would hopefully give a more readable .emacs init file and make it easier to change my key-bindings in the future.

I'm fairly sure that I could do this myself using a series of hooks, but I wonder if there is any existing or built-in support for this?

Thanks

tensorproduct

Answer 1

I don't know anything about Evil, so I'll give the normal Emacs solution:

(global-set-key [?\s ?e] #'my-eval-last-sexp)
(defvar my-eval-last-sexp-command #'undefined)
(defun my-eval-last-sexp ()
  (interactive)
  (call-interactively my-eval-last-sexp-command))
(add-hook 'emacs-lisp-mode-hook
          (lambda () (set (make-local-variable 'my-eval-last-sexp-command) #'eval-last-sexp))
(add-hook 'lisp-mode-hook
          (lambda () (set (make-local-variable 'my-eval-last-sexp-command) #'slime-eval-last-expression))
...

As you can see, there's only one mention of the key you want (in this case [?\s ?e]). But you don't save much on the amount of code you have to write. You might improve it by making my-eval-last-sexp a bit more complex (e.g. it could try to guess the command name from the major mode name), or by replacing the hook function with a global alist.

Hopefully, in some future Emacs, all such source-code modes that interact with some interpreter/compiler will share more of their code so that your problem will simply disappear.