Hammerspoon - nerd customization to the macs

The quest to get a mac to do exactly what I want

It all started because I use a weird keyboard. When I don't have this keyboard plugged in, I want my laptop keyboard map to use dvorak, but since my keyboard is dvorak in hardware, when it's plugged in, the laptop's keyboard map needs to be switched to qwerty otherwise I get a kind of "double dvorak" and everything goes down an extremely strange rabbit hole. Now normally it wouldn't be that much of a hassle to just change it when I'm plugging or unplugging my keyboard, but I found myself in a situation when I kept having to take my laptop to one or other meeting, meaning that I would be plugging and unplugging the keyboard and flipping the setting multiple times a day.

As a nerd, this grates. The computer should just know that if I have that keyboard plugged in I want the keyboard mapping to be qwerty and otherwise I want it to be dvorak. Happily, this is where hammerspoon comes in. Hammerspoon is a framework that allows you to program all kinds of little customizations for mac. Here's how you do the keyboard tweak I wanted:

-- Watch for planck keyboard add/remove and set the keyboard layout appropriately
function usbDeviceCallback(data)
    -- Skip internal memory card as it spams an event on suspend/resume
    if (data["productName"] ~= "Internal Memory Card Reader") then
        hs.alert(data["productName"] .. " " .. data["eventType"])

    if (data["productName"] == "Planck") then
        if (data["eventType"] == "added") then
            --when we add the planck, change the hardware layout to dvorak and turn the OS key 
            --layout to qwerty
        elseif (data["eventType"] == "removed") then
            --when we remove the planck, change the hardware layout to qwerty.  It's up to the 
            --OS to give me dvorak
usbWatcher = hs.usb.watcher.new(usbDeviceCallback)

...but of course this turned out to be a gateway drug for all kinds of further customizations. How about a thing that starts the annoying WeWork printer client thing whenever I'm at WeWork? (Yup. Done). Automatically tweaks my brightness taking into account my battery percentage and the ambient brightness of the room I'm in? (Yup. Easy peasy). Set a default layout of windows whenever I plug my laptop into an external monitor? (Sure) I've now also got it so I can do almost all window movement and resizing via the keyboard.

Any case, my full config is here. Feel free to take from it anything that's usable. The grid resizing thing has a minor bug that I've not been annoyed enough to fix yet, where on certain sizes of monitor it doesn't realise your window is on at the bottom, so you need to move it up to resize. Other than that it's tickety-boo. I highly recommend checking hammerspoon out if you can code a little and want to tweak a Mac to behave exactly the way you want.

Unless otherwise specified the contents of this page are copyright © 2015 Sean Hunter. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.