To install this package, run in Emacs:
M-x package-install RET hydra RET
This package can be used to tie related commands into a family of short bindings with a common prefix - a Hydra. Once you summon the Hydra (through the prefixed binding), all the heads can be called in succession with only a short extension. The Hydra is vanquished once Hercules, any binding that isn't the Hydra's head, arrives. Note that Hercules, besides vanquishing the Hydra, will still serve his orignal purpose, calling his proper command. This makes the Hydra very seamless, it's like a minor mode that disables itself automagically. Here's an example Hydra, bound in the global map (you can use any keymap in place of `global-map'): (defhydra hydra-zoom (global-map "<f2>") "zoom" ("g" text-scale-increase "in") ("l" text-scale-decrease "out")) It allows to start a command chain either like this: "<f2> gg4ll5g", or "<f2> lgllg". Here's another approach, when you just want a "callable keymap": (defhydra hydra-toggle (:color blue) "toggle" ("a" abbrev-mode "abbrev") ("d" toggle-debug-on-error "debug") ("f" auto-fill-mode "fill") ("t" toggle-truncate-lines "truncate") ("w" whitespace-mode "whitespace") ("q" nil "cancel")) This binds nothing so far, but if you follow up with: (global-set-key (kbd "C-c C-v") 'hydra-toggle/body) you will have bound "C-c C-v a", "C-c C-v d" etc. Knowing that `defhydra' defines e.g. `hydra-toggle/body' command, you can nest Hydras if you wish, with `hydra-toggle/body' possibly becoming a blue head of another Hydra. If you want to learn all intricacies of using `defhydra' without having to figure it all out from this source code, check out the wiki: https://github.com/abo-abo/hydra/wiki. There's a wealth of information there. Everyone is welcome to bring the existing pages up to date and add new ones. Additionally, the file hydra-examples.el serves to demo most of the functionality.