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Emacs Hammerspoon Script
--- Emacs Hammerspoon Script
-- Author: Justin Tanner
-- Email: work@jwtanner.com
-- License: MIT
--- What does this thing do?
-- Allows you to have Emacs *like* keybindings in apps other than Emacs.
-- You can use Ctrl-Space to mark and cut text just like Emacs. Also enables Emacs prefix keys such as Ctrl-xs (save).
--- Installation
-- 1) Download and hammerspoon http://www.hammerspoon.org/
-- 2) Copy emacs_hammerspoon.lua to ~/.hammerspoon/init.lua
-- 3) Reload hammerspoon if already running
--- Keybindings Lookup Table
-- Namespaces:
-- globalOverride overrides both Emacs and non-Emacs apps
-- globalEmacs overrides all apps except those specified in appsWithNativeEmacsKeybindings
-- App Name (eg Google Chrome) specifies app specific exceptions
-- Usage:
-- keys[namespace][modifier-key][key] = {to-modifier, to-key, mark-sensitive, macro}
local keys = {
['globalOverride'] = {
['ctrl'] = {
['t'] = {nil, nil, false, 'macroAltTab'}, -- sorta working
['j'] = {'cmd', 'space', false, nil}
}
},
['globalEmacs'] = {
['ctrl'] = {
['a'] = {'ctrl', 'a', true, nil},
['b'] = {nil, 'left', true, nil},
['d'] = {'ctrl', 'd', false, nil},
['e'] = {'ctrl', 'e', true, nil},
['f'] = {nil, 'right', true, nil},
['g'] = {nil, 'escape', false, nil},
['k'] = {'ctrl', 'k', false, nil},
['n'] = {nil, 'down', true, nil},
['o'] = {nil, 'return', false, nil},
['p'] = {nil, 'up', true, nil},
['r'] = {'cmd', 'f', false, nil},
['s'] = {'cmd', 'f', false, nil},
['v'] = {nil, 'pagedown', true, nil},
['w'] = {'cmd', 'x', false, nil},
['x'] = {nil, nil, false, 'macroStartCtrlX'},
['y'] = {'cmd', 'v', false, nil},
['space'] = {nil, nil, true, 'macroCtrlSpace'},
},
['ctrlXPrefix'] = {
['f'] = {'cmd', 'o', false, nil},
['g'] = {'cmd', 'f', false, nil},
['h'] = {'cmd', 'a', false, nil},
['k'] = {'cmd', 'w', false, nil},
['s'] = {'cmd', 's', false, nil},
['u'] = {'cmd', 'z', false, nil},
['w'] = {{'shift', 'cmd'}, 's', false, nil},
},
['alt'] = {
['f'] = {'alt', 'f', true, nil},
['n'] = {'cmd', 'n', false, nil},
['v'] = {nil, 'pageup', true, nil},
['w'] = {'cmd', 'c', false, nil},
['y'] = {'cmd', 'v', false, nil},
},
['altShift'] = {
['.'] = {nil, 'end', false, nil},
[','] = {nil, 'home', false, nil},
},
},
['Google Chrome'] = {
['ctrlXPrefix'] = {
['b'] = {'cmd', 'b', false, nil},
['f'] = {'cmd', 'l', false, nil},
}
}
}
-- NOTE: Use lower case app names
local appsWithNativeEmacsKeybindings = {
'emacs',
'rubymine',
'terminal'
}
local ctrlXActive = false
local ctrlSpaceActive = false
local currentApp = nil
local emacsMap = hs.hotkey.modal.new()
local overrideMap = hs.hotkey.modal.new()
--- Processes a keybinding. Translates keys or runs a macro.
-- @param mod String containing a modifier such as: ctrl, alt or ctrlXPrefix
-- @param key String containing a key such as: a, b, c, etc
function processKey(mod, key)
return function()
emacsMap:exit()
if ctrlXActive and mod == 'ctrl' then
mod = 'ctrlXPrefix'
end
namespace = 'globalEmacs'
if keybindingExists('globalOverride', mod, key) then
namespace = 'globalOverride'
elseif currentApp ~= nil and keybindingExists(currentApp, mod, key) then
namespace = currentApp
end
if keybindingExists(namespace, mod, key) then
lookupKeyAndTranslate(namespace, mod, key)
else
tapKey(mod, key)
end
emacsMap:enter()
end
end
--- Executes a keystroke with hammerspoon.
-- @param mods String or table containing a modifiers
-- @param key String containing a key such a key
function tapKey(mods, key)
-- Faster than hs.eventtap.keystroke
hs.eventtap.event.newKeyEvent(mods, key, true):post()
hs.eventtap.event.newKeyEvent(mods, key, false):post()
end
--- Looks up a keybinding in the global keybindings table and translates that keybinding or runs a macro.
-- @param namespace String containg the namespace to lookup a key (eg Google Chrome or GlobalEmacs)
-- @param mod String containing a modifier key such as ctrl or alt. Also accepts modifiers with states such as ctrlXPrefix
-- @param key String containing a key such as: a, b or c
function lookupKeyAndTranslate(namespace, mod, key)
config = keys[namespace][mod][key]
toMod = config[1]
toKey = config[2]
ctrlSpaceSensitive = config[3]
toMacro = config[4]
if toMacro ~= nil then
_G[toMacro]()
print('Executing a macro ' .. toMacro)
else
holdShift = (ctrlSpaceSensitive and ctrlSpaceActive)
tapKey(prepModifier(toMod, holdShift), toKey)
print(changingMessage(mod, key, toMod, toKey, holdShift))
end
if not ctrlSpaceSensitive then
ctrlSpaceActive = false
end
if toMacro ~= 'macroStartCtrlX' then
ctrlXActive = false
end
end
function changingMessage(fromMod, fromKey, toMod, toKey, holdingShift)
message = 'Changing ' .. fromMod .. '+' .. fromKey .. ' to '
if holdingShift then
message = message .. 'shift'
end
if type(toMod) == 'string' then
message = message .. toMod
elseif type(toMod) == 'table' then
for index, mod in pairs(toMod) do
message = message .. mod .. '+'
end
end
return message .. ' + ' .. (toKey or '')
end
function prepModifier(mod, holdShift)
if holdShift then
return addShift(mod)
end
if type(mod) == 'string' then
return {mod}
end
return {}
end
function addShift(mod)
if type(mod) == 'string' then
return {'shift', mod}
elseif type(mod) == 'table' then
table.insert(mod, 1, 'shift')
return mod
end
return {'shift'}
end
function keybindingExists(namespace, mod, key)
return (
keys[namespace] ~= nil and
keys[namespace][mod] ~= nil and
keys[namespace][mod][key] ~= nil)
end
function assignKeys()
letters = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'}
for i, letter in ipairs(letters) do
emacsMap:bind('ctrl', letter, processKey('ctrl', letter), nil)
emacsMap:bind('alt', letter, processKey('alt', letter), nil)
end
emacsMap:bind('ctrl', 'space', processKey('ctrl', 'space'), nil)
emacsMap:bind({'alt', 'shift'}, '.', processKey('altShift', '.'), nil)
emacsMap:bind({'alt', 'shift'}, ',', processKey('altShift', ','), nil)
overrideMap:bind('ctrl', 't', processKey('ctrl', 't'), nil)
overrideMap:bind('ctrl', 'j', processKey('ctrl', 'j'), nil)
end
function hasValue (tab, val)
for index, value in ipairs(tab) do
if value == val then
return true
end
end
return false
end
function chooseKeyMap()
if hasValue(appsWithNativeEmacsKeybindings, currentApp:lower()) then
print('Turnning OFF keybindings for: ' .. currentApp)
emacsMap:exit()
else
print('Turning ON keybindings for: ' .. currentApp)
emacsMap:enter()
end
end
function appOnStartup()
app = hs.application.frontmostApplication()
if app ~= nil then
return app:title()
end
end
function appWatcherFunction(appName, eventType, appObject)
if (eventType == hs.application.watcher.activated) then
currentApp = appName
chooseKeyMap()
end
end
-- Macro for apps that map ctrl+k to something else
function macroKillLine()
tapKey({'shift', 'ctrl'}, 'e')
tapKey({}, 'shift')
tapKey({'cmd'}, 'x')
ctrlSpaceActive = false
end
function macroAltTab()
-- Include minimized/hidden windows (sorta works)
switcher_space = hs.window.switcher.new(hs.window.filter.new():setCurrentSpace(true):setDefaultFilter{})
switcher_space.nextWindow()
window = hs.window.frontmostWindow()
window:focus()
end
function macroCtrlSpace()
ctrlSpaceActive = not ctrlSpaceActive
tapKey({}, 'shift')
end
function macroStartCtrlX()
ctrlXActive = true
hs.timer.doAfter(0.75,function() ctrlXActive = false end)
end
-- Application start
print('---------------------------------')
print('Starting Emacs hammerspoon Script')
assignKeys()
currentApp = appOnStartup()
chooseKeyMap()
local appWatcher = hs.application.watcher.new(appWatcherFunction)
appWatcher:start()
overrideMap:enter()
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