On OS X, you're looking for Hammerspoon. It uses Lua for its scripting engine. Not sure there's quite an equivalent for the executable feature, but it does su

On OS X, you're looking for Hammerspoon. It uses Lua for its scripting engine. Not sure there's quite an equivalent for the executable feature, but it does support publishing and installing modules written by users, which are called 'spoons', IIRC.