> Are you implying Doug McIlroy hadn't been taught about (and inevitably > occupied by) Church-Turing Thesis or even before that Ackermann function and > had to wait to be inspired by a comment in passing about FORTRAN to realize > the importance of recursion?! This was a rhetorical question, of course.
Doug loves that story. In the version he told me, he was a (math) grad student at MIT in 1956 (before FORTRAN) and the discussion in the lab was about computer subroutines - in assembly or machine language of course. Someone mused about what might happen if a subroutine called itself. Everyone looked bemused. The next day they all returned and declared that they knew how to implement a subroutine that could call itself although they had no idea what use it would be. "Recursion" was not a word in computing. Hell, "computing" wasn't even much of a word in math. Don't be Whiggish in your understanding of history. Its participants did not know their way. -rob
