That's an interesting statement. I always assumed they were much older -- and that the current detour into 'lines of ASCII text' were a mere implementation detail, driven by historical accident.
This[1] sure looks like a simple dataflow program to me, even if Gauss never intended it to be implemented on a von Neumann machine.
I hate writing programs as text, but unfortunately, "text is the universal interface" right now. It's easy to save, and diff and patch, and edit. There isn't a general-purpose format for saving graphs, diffing/patching them, or a decent selection of editors for them.
In 50 years, I'm sure we'll look back on today's programming the same way we now look back on the pre-visual-editor era. You had the technology to create general-purpose graph editors, but you didn't have or use any? Why not?
[1]: https://en.wikipedia.org/wiki/Cooley–Tukey_FFT_algorithm#/me...