Declaring Bindings While Destructuring

Coordinating Coordinates

In the Quil GUI of my tic-tac-toe app, I have a mouse-over? function to detect if the mouse is within the same range of coordinates as a given button on the screen. In order to do this, the function needs four parameter regarding the button in question: the button's X and Y coordinates, width, and height. I first created this function when getting hover effects working, so it was using mouse-x and mouse-y functions inside the function body to get the mouse position.

Once I started implementing Quil's :handle-click option, I discovered that it passes an object with the mouse's coordinates at the time it was clicked. As such, I wanted to update mouse-over? to accept these coordinates as arguments.

There was just one small issue, though: mouse-over? already had an x and y parameters, so I couldn't simply destructure the keys from the map that :handle-click passes, like this:

(defn mouse-over? [x y w h {:keys [x y]}]
    fn-body)

I also didn't want to destructure inside the function body if I could avoid it, like this:

(defn mouse-over? [x y w h mouse-xy]
    (let [{mouse-x :x
           mouse-y :y} mouse-xy]
       fn-body))

With a little bit of playing around in the REPL, I discovered it was possible to declare new bindings while destructuring all inside of the function parameters, like this:

(defn mouse-over? [x y w h {mouse-x :x mouse-y :y}]
    fn-body)

Pretty cool, huh?