Creates a QR code from STDIN
qr is an optional builtin which generates a PNG format image based on the input from STDIN.
qr must be run as a method.
<stdin> -> qr -> <stdout>
Write the PNG to disk
» out "Hello, World!" -> qr -> > qr.png
Display PNG in the terminal
» out "Hello, World!" -> qr -> open-image
qr sets stdout's data-type to be "image", which is defined in with the
open-image optional builtin. So if you have that disabled then you may have to
cast the output in some circumstances.
cast: Alters the data type of the previous function without altering it's output
open-image: Renders bitmap image data on your terminal