>fighter) went a step further. It disallowed both subroutine calls and
>backward branches, except for the one at the bottom of the main loop.
>Control flow went forward only. Sometimes one piece of code had to leave
>a note for a later piece telling it what to do, but this worked out well
>for testing: all data was allocated statically, and monitoring those
>variables gave a clear picture of most everything the software was doing.
>The software did only the bare essentials, and of course, they were
>serious about thorough ground testing.
>No bug has ever been found in the "released for flight" versions of that code.
I was pretty excited to learn more about that style, and then I came across...
https://www.flightglobal.com/FlightPDFArchive/1989/1989%20-%...
...but I'd still like to know more about this style of programming, and languages that facilitate programming in that manner.