[[https://melpa.org/#/hercules][file:https://melpa.org/packages/hercules-badge.svg]] [[https://stable.melpa.org/#/hercules][file:https://stable.melpa.org/packages/hercules-badge.svg]]
[[./hercules.png]]
An auto-magical, =which-key= based =hydra= banisher.
(hercules-def :toggle-funs #'macrostep-mode :keymap 'macrostep-keymap)
(define-key
[[./hercules.gif]]
*** Value Proposition Say that you want to move to the next =babel= source block in an =org= file, and then realize you actually want to execute the one after that. You would need to press =C-c C-v n C-c C-v n C-c C-v e=. Quite a lengthy combination.
But if add this you your init file:
(hercules-def ;; read further to see why this works :toggle-funs #'org-babel-mode :keymap 'org-babel-map :transient t)
;; tweak binding to taste (define-key org-mode-map (kbd "C-c C-v") #'org-babel-mode)
You would only need to press =C-c C-v n n e=, and while you're doing so, you would get a pop-up listing all the keybindings that follow =C-c C-v= in case you forget. Because of the =:transient= keyword, once you press a key that's not in the pop-up, the =hercules.el= window will disappear and you will be dropped back into your regular bindings.
** Relative to Other Packages If only there was a way to make a =hydra= without having to list all the bindings explicitly... Kind of like =which-key=...
=hercules.el= implements the functionality of [[https://github.com/abo-abo/hydra][hydra]] by leveraging [[https://github.com/justbur/emacs-which-key][which-key]] auto-magic.
Unlike =hydra=, =hercules.el= entry and exit points are associated with functions, not keys. Keys, on the other hand, are defined by traditional keymaps, which you can use as-is, or tweak to your liking using your tool of choice. =hercules.el= doesn't force this choice on you. That said, I highly recommend [[https://github.com/noctuid/general.el][general.el]].
Ultimately, =hercules.el= saves you time by relying on work that has already been done for you --- usually, but not necessarily, as part of a time-tested minor-mode. The resulting interfaces tend to be more comprehensive than home-grown =hydras=, thus aiding you in discovering new functionality.
Allow me to illustrate my point using an example from =hydras= README:
*** Hydra Setup
(defhydra hydra-buffer-menu (:color pink :hint nil) " ^Mark^ ^Unmark^ ^Actions^ ^Search ^^^^^^^^----------------------------------------------------------------- m: mark u: unmark x: execute R: re-isearch s: save U: unmark up b: bury I: isearch d: delete ^ ^ g: refresh O: multi-occur D: delete up ^ ^ T: files only: % -28`Buffer-menu-files-only ~: modified " ("m" Buffer-menu-mark) ("u" Buffer-menu-unmark) ("U" Buffer-menu-backup-unmark) ("d" Buffer-menu-delete) ("D" Buffer-menu-delete-backwards) ("s" Buffer-menu-save) ("~" Buffer-menu-not-modified) ("x" Buffer-menu-execute) ("b" Buffer-menu-bury) ("g" revert-buffer) ("T" Buffer-menu-toggle-files-only) ("O" Buffer-menu-multi-occur :color blue) ("I" Buffer-menu-isearch-buffers :color blue) ("R" Buffer-menu-isearch-buffers-regexp :color blue) ("c" nil "cancel") ("v" Buffer-menu-select "select" :color blue) ("o" Buffer-menu-other-window "other-window" :color blue) ("q" quit-window "quit" :color blue))
(define-key Buffer-menu-mode-map "." 'hydra-buffer-menu/body)
*** hercules.el Setup NOTE: This is the equivalent of hydra's buffer setup applied to window manipulation, since I don't use buffer-menu. Implementing it yourself should be trivial.
(hercules-def :show-funs #'windresize :hide-funs '(windresize-exit windresize-cancel-and-quit) :keymap 'windresize-map)
(define-key
** Bonus Last, and definitely least, =hercules.el= provides a more consistent interface for all your keybinding popup needs (the same =which-key= UI throughout your config).
Motivation As mentioned, I initially wrote =hercules.el= to avoid reinventing the wheel by creating elaborate hydras for minor-modes that already worked like they had them, merely lacking the handy popup. These include:
=macrostep-mode=
=edebug-mode=
=debugger-mode=
=windresize=
many more
But =hercules.el= can use any keymap you have lying around, even if there's no mode associated with it. Just make one up. For example, you can steal =org-babel-map= and whip up what used to be a massive =hydra= in seconds:
(hercules-def :toggle-funs #'org-babel-mode :keymap 'org-babel-map :transient t)
(define-key
Pressing any key outside the map will leave the pseudo-mode and hide the =hercules.el= pop-up if TRANSIENT is =t=. But you can also use the HIDE-FUNS and TOGGLE-FUNS arguments to do the same while executing one last Hail Mary command. Combining them is not a problem either.
Too crowded for you?
(hercules-def :toggle-funs #'org-babel-mode :keymap 'org-babel-map :whitelist-keys '("n" "p" "t") :transient t)
(define-key
You can also use BLACKLIST-KEYS, BLACKLIST-FUNS, and WHITELIST-FUNS. to this end.
What about defining =hercules.el= pop-ups from scratch? Easy. Keep in mind this would usually take 4 =defhydra= calls that would need to be explicitly connected.
(general-def :prefix-map 'my-random-map "f" #'foo "b" #'bar "z" #'baz "m" '(:ignore t :wk "mmap") "mf" #'mfoo "mb" #'mbar "mz" #'mbaz "n" '(:ignore t :wk "nmap") "nf" #'nfoo "nb" #'nbar "nz" #'nbaz "o" '(:ignore t :wk "omap") "of" #'ofoo "ob" #'obar "oz" #'obaz)
(hercules-def :toggle-funs #'my-random-mode :keymap 'my-random-map :transient t)
(define-key
Want to still see the entire keymap on prefix-key press? Done. Just call =hercules-def= like so instead:
(hercules-def :toggle-funs #'my-random-mode :keymap 'my-random-map :transient t ;; flatten nested keymaps :flatten t)
* Arguments TOGGLE-FUNS, SHOW-FUNS, and HIDE-FUNS define entry and exit points for hercules.el to show KEYMAP*. Both single functions and lists work. As all other arguments to =hercules-def=, these must be quoted.
KEYMAP specifies the keymap for =hercules.el= to make a pop-up out of. If KEYMAP is =nil=, it is assumed that one of SHOW-FUNS or TOGGLE-FUNS results in a =which-key--show-popup= call. This may be useful for functions such as =which-key-show-top-level=. I use it to remind myself of some obscure Evil commands from time to time.
FLATTEN displays all maps and sub-maps together, without redrawing on prefix-key presses. This allows for multi-key combinations in a single =hercules.el= buffer.
BLACKLIST-KEYS and WHITELIST-KEYS specify which (=kbd= interpretable) keys should removed from/allowed to remain on KEYMAP. Handy if you want to unbind things in bulk and don't want to get your hands dirty with keymaps. Both single characters and lists work. Blacklists take precedence over whitelists.
BLACKLIST-FUNS and WHITELIST-FUNS are analogous to BLACKLIST-KEYS and WHITELIST-KEYS except that they operate on function symbols. These might be useful if a keymap specifies multiple bindings for a commands and pruning it is more efficient this way. Blacklists again take precedence over whitelists.
PACKAGE must be passed along with BLACKLIST-KEYS, WHITELIST-KEYS, BLACKLIST-FUNS, or WHITELIST-FUNS if KEYMAP belongs to a lazy loaded package. Its contents should be the package name as a quoted symbol.
Setting TRANSIENT to =t= allows you to get away with not setting HIDE-FUNS or TOGGLE-FUNS by dismissing hercules.el whenever you press a key not on KEYMAP.