Well, the interferometer is not programmable by typing in commands into a classical computer, but it is programmable by instructing the relevant grad students. In other words, we do have an algorithm to create any interferometer we choose.
It's funny, but I am also serious. Historically speaking, the idea that computational devices could have internal stored programs that could be used to drive any function, rather than humans putting in effort every time to program, had to invented.
Yeah but our standards for computers are higher nowadays.
I covered analog computers in school, which as I recall consisted of integrating blocks made with linear circuits. You combine them up as needed to simulate systems of linear differential equations. There was still a degree of programmability in that sense.
it doesn't strike me as impossible or impractical that programmable interferometers could be constructed in the near future. Is there any limit blocking this today?
I agree, the rabbit hole goes deep.