From bill@amber.ssd.csd.harris.com Tue Feb 1 11:42:09 1994 Received: from travis.csd.harris.com by dkuug.dk with SMTP id AA12132 (5.65c8/IDA-1.4.4j for ); Tue, 1 Feb 1994 22:42:25 +0100 Received: from amber.ssd.csd.harris.com by travis.csd.harris.com (5.61/harris-5.1) id AA29654; Tue, 1 Feb 94 16:42:11 -0500 Received: by amber (5.61/CX/UX-5.0) id AA10525; Tue, 1 Feb 94 16:42:09 -0500 Date: Tue, 1 Feb 94 16:42:09 -0500 From: bill@amber.ssd.csd.harris.com (Bill Leonard) Message-Id: <9402012142.AA10525@amber> To: dtm@castle.ed.ac.uk Cc: sc22wg5@dkuug.dk In-Reply-To: <199402012006.AA08782@dkuug.dk> (message from D Muxworthy on 01 Feb 94 18:24:14 GMT) Subject: Re: (SC22WG5.487) Comp.lang.fortran comments on evolution X-Charset: ASCII X-Char-Esc: 29 > Date: 01 Feb 94 18:24:14 GMT > From: D Muxworthy > On the other hand, there are some forward looking users, as evidenced by this > quote: > > And, a Common statement should allow Character variables to reside > > with any other variable types. Once again, VS Fortran allows this -- > > as an extension. > And an extension it should remain, in my opinion. Programmers should not be > encouraged to do this sort of thing. Besides, there is already a workaround > in the form of internal I/O (with the A format descriptor). And of course > COMMON itself should be on the way out. As soon as I get a Fortran 90 > compiler, I'll convert all my common blocks to modules. > --------------------------------------------------------------------------- Well, I'd take this response with a large block of salt, since it appears that the commentor didn't know what he was talking about. I can't see how internal I/O with an A format descriptor is a workaround for having CHARACTER and non-CHARACTER data in a single COMMON block. The fact is, there is no technical reason for this restriction to remain. It is a holdover from ancient architectures. Furthermore, F90 now allows structures containing both CHARACTER and non-CHARACTER data, and COMMON is nothing more than a big structure. So what's the problem? I'm always suspicious of comments such as "As soon as I get a Fortran 90 compiler, I'll convert all my common blocks to modules." I suspect that person either doesn't have very much Fortran code or else he has lots too much spare time on his hands! Most real-life programmers don't have time (or the money) to convert huge amounts of code unless it is absolutely necessary. So the code either gets converted in small chunks (which is hard to do with COMMON blocks), or never gets converted until it is rewritten or simply thrown away. I am not saying that language evolution is always bad. But like genetic evolution, it must go slowly if it is to have more beneficial than detrimental effect. Bill Leonard Harris Computer Systems Division 2101 W. Cypress Creek Road Fort Lauderdale, FL 33309 bill@ssd.csd.harris.com These opinions and statements are my own and do not necessarily reflect the opinions or positions of Harris Corporation. ------------------------------------------------------------------------------ "Governments, like individuals, spend money for any or all of three reasons: because they want to, because they have to, or because they have it to spend." Rex Stout ------------------------------------------------------------------------------