Towards FORTRAN VI

Scientific computing in Great Britain has changed quite markedly since the Flowers' report appeared in December 1965, and one aspect of this change is the increased acceptance of FORTRAN. It is now taken for granted that any computer for scientific use will possess a FORTRAN compiler, and that this will be compatible with one or other of the ASA specifications (American Standards Association, 1964, 1965). As well as this, most FORTRAN IV compilers now offer a range of features over and above the minimum needed for ASA compatibility. If these extra features are examined a certain measure of agreement between the different compilers is apparent, and this leads to the idea that the time is ripe for a third level of 'standard FORTRAN' standing to FORTRAN IV much as this does to FORTRAN II or ASA Basic FORTRAN. This note aims at setting out some ideas for such a language. It is in many ways remarkable that a language as old as FORTRAN is still in use at all, and any 'extended FORTRAN' must be able to stand the competition of newer languages such as ALGOL and PL/I. One reason for survival seems to be the fact that its very limitations, while not too serious from the user's point of view, make it relatively easy to compile. Fast compiling is important for a language much used in teaching since students' exercises spend most of their time in the compiling phase, and indeed the same consideration is important in any research-based computer centre where the ratio of new programs to old will always remain high. It follows from this that an extended FORTRAN, while aiming to remove some of the limitations of FORTRAN IV, should remain simple in structure, and that it may be necessary to exclude features which, while occasionally useful, would complicate the compiler structure to an unacceptable extent.