Eric Smith wrote:
I wrote:There are plenty of legitimate complaints one could make about Fortran, but I've never before heard anyone claim that it is not an HLL. How do you justify that?Michael J. Mahon wrote:The original FORTRAN had limitations quite transparently derived from the 704 architecture, and FORTRAN IV had the limitations raised in accordance with the extensions of the 7094! As an example, the three-level DO loop nesting limit was a consequence of the 704's (and up to 7090's) three index registers.The arithmetic IF was a consequence of the 704/709/709x architecture as well, but nevertheless FORTRAN compilers were developed for other machines.
Right--after everything is Turing equivalent. ;-) The point is that FORTRAN was designed to fit the 704 like a glove, and no other machine was considered. I don't really see any problem with a *machine-oriented* high level language. ;-)
Perhaps "not an HLL" is too strong, but it certainly was not conceived as machine-independent.The amazing thing about a dancing bear isn't how well it dances, but the fact that it dances at all. By modern HLL standards the original Fortran is quite crude, but in 1957, Fortran must have been pretty f@#$ing amazing. For that matter, so was Commercial Translator, the predecessor of COBOL.
FORTRAN certainly was amazing! It's developers knew that the code it generated would be compared to hand-generated assembly, and so they chose the language elements so that translation would map well to the 704 and even included an optimization pass that did a dynamic simulation of program flow to figure out where to make tradeoffs. The FREQUENCY statement that provided the probabilities of conditional branches for this simulation was relatively short-lived, partly because we now know that programmers tend to be *terrible* estimators of branch probabilities! The great lengths they went to to generate good code were a direct result of the total lack of credibility regarding machine-generated code--and FORTRAN won over almost everyone eventually. -michael NadaPong: Network game demo for Apple II computers! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."