[derefr]

Now that's an intriguing concept. "A file format for declaratively specifying a physical data-communication artefact, abstractly-defined by the interactions it supports."

• Just showing the user text? Compiles to plaintext.

• Get the user to give some input? Compiles to a styled form, as PostScript.

• Add radio buttons? Compiles to a physical form but with a 3D-printed notched slider glued to it.

• Require validation for freeform-text form fields? Compiles to a 3D-print + VLSI + pick-and-place specification for a tablet embedded-device that displays the form and does the validation.

Now imagine a "printer" that takes such abstract documents as input, and can print any of these... :)